DanKWiki

build-pipeline-plugin Notes

Fri, 28 Sep 2012 01:31:54 -0400

Jenkins build-pipeline-plugin - Google Code Page

Plugin Development References

Plugin tutorial - Jenkins Wiki

Building:

mvn install

Testing:

mvn hpi:run -Djetty.port=8090

build-pipeline-plugin Code References

Conference Notes

Wed, 24 Sep 2008 01:06:45 -0400

Conference Notes

Notes from various conferences or training events I've attended.

CVS Notes

Mon, 20 Dec 2010 01:59:48 -0400

CVS Notes

Essential CVS (free online book)
CVS Quick Reference

.cvsrc File

Common .csvrc settings:

cvs -q
update -dP
diff -uN

Branches

Create a new Branch

Creating a branchpoint from something other than head:

 cvs rtag -r <TAG TO BRANCH FROM> <BRANCH POINT TAG> cvs_project_name

then

 cvs rtag -b -r <BRANCH POINT TAG> <BRANCH TAG> cvs_project_name

e.g.

 cvs rtag -r MYPROJECT_1_2 MYPROJECT_1_2_BP myproject

 cvs rtag -b -r MYPROJECT_1_2_BP MYPROJECT_NEW_WORK_BR myproject

or just

 cvs rtag -b -r MYPROJECT_1_2 MYPROJECT_NEW_WORK_BR myproject

Update a Branch from HEAD

To update a branch with the latest from HEAD:

 cvs update -j HEAD

Merge from a Branch to HEAD

 cvs update -dj <BRANCH TAG>

Merge from a Branch to another Branch

Merging a project branch to HEAD:

place an end point (EP) tag on project branch
update target branch (or HEAD), and optionally set a pre-merge tag
go to target branch (or HEAD) root
cvs update -dj <BRANCH POINT TAG> -j <END POINT TAG>

Assuming a branch point tag (ordinary tag) has been created:

 cvs update -dj <BRANCH POINT TAG> -j <MERGE POINT ON HEAD TAG>

Examples:

 cvs update -dj MYPROJECT_BP -j MYPROJECT_1_3
 
 cvs update -P -dj MYPROJECT_1_2 -j MYPROJECT_1_3

If no branch point tag (ordinary tag) has been created (at target root):

 cvs update -j <BRANCH TAG>

Example:

 cvs update -j MYPROJECT_BR

To do a run through without making changes use -n:

 cvs -n update -dj <BRANCH POINT TAG> -j <MERGE POINT ON HEAD TAG>

To prune empty directories:

                                                                        
 cvs update -P -dj <BRANCH POINT TAG> -j <MERGE POINT ON HEAD TAG>

 cvs update -P -dj MYPROJECT_BP -j MYPROJECT_EP

To ignore $id$ tag differences use the -kk option:

 cvs update -P -kk -dj MYPROJECT_BP -j MYPROJECT_EP

But this creates a sticky tag situation if you're on HEAD, so you need to then remove the sticky tag:

 cvs update -A

Remove a Branch

Note: only do this if it was just created and there has been no activity on it!

 cvs rtag -d -B <BRANCH TAG> cvs_project_name

Diffs

Diff Two Tags

 cvs diff -u -r <BRANCH POINT TAG> -r <MERGE POINT ON HEAD TAG>

 cvs diff -u -r MYPROJECT_1_2 -r MYPROJECT_1_3

Changes made in Branch

Requires a branch point tag to compare against (-kk: ignore CVS id tags).

List files changed (rdiff -s: summary change report):

 cvs -q rdiff -s -kk -r MYPROJECT_BP -r MYPROJECT_BR myproject

 cvs -q rdiff -s -kk -r MYPROJECT_VERSION_1 -r MYPROJECT_VERSION_2 myproject

 cvs -q rdiff -s -kk -r MYPROJECT_VERSION_1 -r MYPROJECT_VERSION_2 myproject/folder

List files and changes:

 cvs -q rdiff -u -kk -r MYPROJECT_BP -r MYPROJECT_BR myproject

Details on one file:

 cvs -q rdiff -kk -r MYPROJECT_VERSION_1 -r MYPROJECT_VERSION_2 myproject/folder/file.ext

Data Structures And Algorithm Notes

Wed, 15 Apr 2020 20:40:59 -0400

Data Structures And Algorithm Notes

Data Structures and Algorithms with Object-Oriented Design Patterns in Java (Online Book)

Algorithms

Dictionary of Algorithms and Data Structures
Top Coder Algorithm Tutorials
Damn Cool Algorithms, Part 1: BK-Trees
Search algorithm (Wikipedia)
Sorting algorithm (Wikipedia)
NP-complete (Wikipedia)
Travelling salesman problem (Wikipedia)
Knapsack problem (Wikipedia)
Graph theory (Wikipedia)
Breadth-first search (Wikipedia)
Depth-first search (Wikipedia)

Questions and Topics

Q. Bitwise Operations and Bitwise AND, OR, XOR and NOT Operators and Bit Masks

NOT - Bits that are 0 become 1, and those that are 1 become 0.  Used to unset/turn off bit flags.
AND - Multiplication of bits; i.e., 1 × 0 = 0 and 1 × 1 = 1.  Used to check state of a bit flag.
OR  - 1 if either bit is 1, otherwise 0.  Used to set/turn on bit flags regardless of whether already on or not.
XOR - 1 if both bits are different, 0 if they are the same.  Used to toggle flag bits of a mask.

Arithmetic Shifts: left << (multiplies by 2, 0 shifted on as least significant bit), right >> (divides by 2, left-most sign bit is retained)
Logical Shift: right >>> (divides by 2, 0 shifted on as most significant bit)

Q. What's the difference between a LinkedList and an ArrayList (or between a linked list and an array/vector)?

An ArrayList is a List implementation backed by a Java array. With a LinkedList, the List implementation is backed by a 
doubly linked list data structure.

Q. How can you detect a cycle in a linked list?

Turtle and Rabbit: The idea is to have two references to the list and move them at different speeds. Move one forward by 1  
node and the other by 2 nodes. If the linked list has a loop they will meet. If there is no loop either of the references 
will become null when it reaches the end of the list. O(n)

Q. What is a weighted round robin load balancing algorithm?

Round robin distribution is used by DNS servers, peer-to-peer networks, and many other multiple-node clusters/networks.  
In a weighted round-robin algorithm, each destination (in this case, server) is assigned a value that signifies, relative 
to the other servers in the list, how that server performs. This "weight" determines how many more (or fewer) requests are 
sent that server's way; compared to the other servers on the list.

Q. Breadth first search

root, children (enqueue/add), children of children (dequeue/remove first and enqueue), etc... Use a fifo queue

Typical applications:
- Shortest path between two vertices.

public class BreadthFirstPaths {

    private boolean[] marked;
    private int[] edgeTo;

    ...
    
    private void bfs(Graph G, int s) {
        Queue<Integer> q = new Queue<Integer>();
        q.enqueue(s);
        marked[s] = true;
        while (!q.isEmpty()) {
            int v = q.dequeue();
            for (int w : G.adj(v)) {
                if (!marked[w]) {
                    q.enqueue(w);
                    marked[w] = true;
                    edgeTo[w] = v;
                }
            }
        }
    }
}

Q. Depth first search

root, children (push) to leaf nodes, left, then up (pop) and right... Use a stack
    +
  3   4
preorder/prefix (Polish notation, e.g. + 3 4), postorder/postfix (reverse Polish notation, e.g. 3 4 +), 
inorder/infix (e.g. 3 + 4) - expression tree

Recursive algorithm.

Typical applications:
- Find all vertices connected to a given source vertex.
- Find a path between two vertices.

After DFS, should be able to:
- Find vertices connected to root/source in constant time
- Find a path back to root/source in time proportional to its length

public class DepthFirstPaths {

    private boolean[] marked;
    private int[] edgeTo;
    private int s;

    public DepthFirstSearch(Graph G, int s) {
        ...
        dfs(G, s);
    }

    private void dfs(Graph G, int v) {
        marked[v] = true;
        for (int w : G.adj(v))
            if (!marked[w]) {
                dfs(G, w);
                edgeTo[w] = v;
            }
    }
}

Q. Name some self balancing binary trees

Red/black tree, splay tree, AVL tree

Q. What is Big-O Notation?

Defines worst case performance of an algorithm (ex: O(N)).  There is also Omega (best case - ex: Ω(N)) and Theta (average case - ex: Θ(N)).
Given N we might have, N, N log N, N^2 performance, for example.

Q. Merge sort

Split in 2, recurse left, recurse right, merge sorted halves.

Can be "stable" - i.e. retains existing sorts if order of equal items is not changed, and no long distance exchanges are made.

Java sorts Objects with a merge sort algorithm.  N log N.

public class MergeSort {

    public static void sort(Object[] a, Comparator comparator) {
        Object[] aux = new Object[a.length];
        sort(a, aux, comparator, 0, a.length - 1);
    }

    private static void sort(Object[] a, Object[] aux, Comparator c, int lo, int hi) {
        // Optimize sort for small subarrays (CUTOFF = 7 perhaps):
        if (hi <= lo + CUTOFF - 1) {
            Insertion.sort(a, c, lo, hi);
            return;
        }

        int mid = lo + (hi - lo) / 2;
        sort(a, aux, c, lo, mid);
        sort(a, aux, c, mid + 1, hi);

        // Optimize if already sorted:
        if (!less(c, a[mid + 1], a[mid])) return;

        merge(a, aux, c, lo, mid, hi);
    }

    private static void merge(Object[] a, Object[] aux, Comparator c, int lo, int mid, int hi) {
        assert isSorted(a, c, lo, mid);      // precondition: a[lo..mid] sorted
        assert isSorted(a, c, mid + 1, hi);  // precondition: a[mid+1..hi] sorted

        // Copy to working array:
        for (int k = lo; k <= hi; k++)
            aux[k] = a[k];

        // Merge two arrays:
        int i = lo, j = mid + 1;
        for (int k = lo; k <= hi; k++) {
            if (i > mid)                      a[k] = aux[j++];
            else if (j > hi)                  a[k] = aux[i++];
            else if (less(c, aux[j], aux[i])) a[k] = aux[j++];
            else                              a[k] = aux[i++];
        }

        assert isSorted(a, c, lo, hi);       // postcondition: a[lo..hi] sorted
    }

    ...

}

Q. Quick sort

Randomly shuffle array to prep process and avoid worst case comparisons (~1/2 * N^2) which becomes very unlikely to happen (if shuffle actually 
sorted the array!)
Then pick a partitioning element as a divide/pivot point, less vs. greater, exchange elements that are out of place, recurse.

Is not "stable".

Faster than Merge sort because less movement of items even though more compares in average case.  N log N.  Too many duplicate keys can also 
affect efficiency.

Java sorts primitive types with a quick sort algorithm.

public class QuickSort {

    private static int partition(Comparable[] a, int lo, int hi) {
        int i = lo, j = hi + 1;
        while (true) {
            while (less(a[++i], a[lo])) // find item on left to swap
                if (i == hi) break;

            while (less(a[lo], a[--j])) // find item on right to swap
                if (j == lo) break;

            if (i >= j) break;          // check if pointers cross
            exch(a, i, j);              // swap items
        }
        exch(a, lo, j);                 // swap with partitioning item
        return j;                       // return index of item now known to be in place
    }

    public static void sort(Comparable[] a) {
        StdRandom.shuffle(a);  // shuffle ensures performance is good
        sort(a, 0, a.length - 1);
    }

    private static void sort(Comparable[] a, int lo, int hi) {
        // Optimize sort for small subarrays (CUTOFF between 10 and 20):
        if (hi <= lo + CUTOFF - 1) {
            Insertion.sort(a, lo, hi);
            return;
        }
        
        int j = partition(a, lo, hi);
        sort(a, lo, j - 1);
        sort(a, j + 1, hi);
    }
}

Q. Sorting Summary

Q. Implement a hashtable (dictionary)

An array of linked lists, indexed by a hash, where hash collisions are placed in buckets in the linked list.

Q. Binary search trees

left subtree nodes < parent node <= right subtree nodes.  Efficient for sorting, searching in-order.

public class BST<Key extends Comparable<Key>, Value> {
    private Node root;             // root of BST

    private class Node {
        private Key key;           // sorted by key
        private Value val;         // associated data
        private Node left, right;  // left and right subtrees

        public Node(Key key, Value val, int N) {
            this.key = key;
            this.val = val;
            this.N = N;
        }
    }

    // return value associated with the given key, or null if no such key exists
    public Value get(Key key) {
        return get(root, key);
    }

    private Value get(Node x, Key key) {
        if (x == null) return null;

        int cmp = key.compareTo(x.key);

        if      (cmp < 0) return get(x.left, key);
        else if (cmp > 0) return get(x.right, key);
        else              return x.val;
    }


    /***********************************************************************
    *  Insert key-value pair into BST
    *  If key already exists, update with new value
    ***********************************************************************/
    public void put(Key key, Value val) {
        root = put(root, key, val);
    }

    private Node put(Node x, Key key, Value val) {
        if (x == null) return new Node(key, val, 1);

        int cmp = key.compareTo(x.key);

        if      (cmp < 0) x.left  = put(x.left,  key, val);
        else if (cmp > 0) x.right = put(x.right, key, val);
        else              x.val   = val;

        return x;
    }
}

Q. Heap (priority queue)

Complete binary tree (i.e. only bottom level might not be complete, left to right), 
heap ordered (i.e. parent values > children values)

Q. Graphs

trees with interconnecting nodes

Q. Graph algorithms, such as Dijkstra and A*

Best-first search is a search algorithm which explores a graph by expanding the most promising node chosen 
according to a specified rule.  A* uses a best-first search and finds the least-cost path from a given initial
node to one goal node (out of one or more possible goals).  It uses a distance-plus-cost heuristic  function 
(usually denoted f(x)) to determine the order in which the search visits nodes in the tree.
  
Dijkstra's algorithm, conceived by Dutch computer scientist Edsger Dijkstra in 1959,[1]  is a graph search 
algorithm that solves the single-source shortest path problem for a graph with nonnegative edge path costs, 
producing a shortest path tree. This algorithm is often used in routing.

Q. NP-complete problems, such as traveling salesman and the knapsack problem

Traveling Salesman problem: Given a list of cities and their pairwise distances, the task is to find a shortest 
possible tour that visits each city exactly once.

Knapsack problem: Given a set of items, each with a weight and a value, determine the number of each item to 
include in a collection so that the total weight is less than a given limit and the total value is as large as 
possible.

DokuWiki Notes

Fri, 26 Apr 2013 15:02:12 -0400

DokuWiki Notes

Plugins

Plugins can be found at http://www.dokuwiki.org/plugins

blockquotes

Plugin Documentation: http://foosel.org/snippets/dokuwiki/blockquote

Example usage:

<blockquote>This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. 
This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. 
This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. 
This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. 
This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. 
This is a sample of blockquoted text. This is a sample of blockquoted text.</blockquote>

which produces:

This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text. This is a sample of blockquoted text.

Example usage:

<blockquote J. Random Hacker>Test with a cite attribute...</blockquote>

which produces:

Test with a cite attribute…

Example usage:

<blockquote>Test with a cite command...<cite>J. Random Hacker, [[http://localhost/~jrhacker]]</cite></blockquote>

which produces:

Test with a cite command…
J. Random Hacker, http://localhost/~jrhacker

comment

Plugin Documentation: http://wiki.splitbrain.org/plugin:comment

Example usage:

<color red>Visible Text /* can't see this */ surrounding hidden text</color>

which produces:

Visible Text surrounding hidden text

syntaxhighlighter

Plugin Documentation: http://www.dokuwiki.org/plugin:syntaxhighlighter

Example usage:

<code java::showcontrols>
public void sampleMethod(String inputString) {
  String setMe = "The String Setting";
  int index = 0;
  while (index < 10) {
    System.out.println(setMe);
    index++;
  }
  System.out.println("The original string inputted was: " + inputString);
}
</code>

which produces:

  public void sampleMethod(String inputString) {
    String setMe = "The String Setting";
    int index = 0;
    while (index < 10) {
      System.out.println(setMe);
      index++;
    }
    System.out.println("The original string inputted was: " + inputString);
  }

Language Aliases - The following languages are supported:

Language	Aliases
C++	cpp, c, c++
C#	c#, c-sharp, csharp
CSS	css
Delphi	delphi, pascal
Java	java
Java Script	js, jscript, javascript
PHP	php
Python	py, python
Ruby	rb, ruby, rails, ror
Sql	sql
VB	vb, vb.net
XML/HTML	xml, html, xhtml, xslt

Configuration Options - The options are passed together with the language alias and are separated by a colon character.

For example: <code java:showcontrols:firstline[5]> … </code>

Options
lang	Language Alias (see above).
nogutter	Will display no gutter.
showcontrols	Will display controls at the top.
collapse	Will collapse the block by default.
firstline[value]	Will begin line count at value. Default value is 1.
showcolumns	Will show row columns in the first line.

Git Notes

Tue, 07 Mar 2017 14:36:05 -0400

Git Notes

Git Reference
Git Immersion - Guided tour through Git
Think Like (a) Git - A Guide for the Perplexed
Git data flow diagram
A Git Workflow
Pro Git (Free HTML Book)

GitHub

defunkt/hub - Command line tool that wraps git in order to extend it with extra features and commands that make working with GitHub easier.
Emoji cheat sheet for Campfire and GitHub (Emoticons)
GitHub Flow (vs. git-flow)

Tools

Git in Eclipse
Git with Eclipse (EGit) - Tutorial
github/GitPad - EXE to make Notepad the Git editor (commits, interactive rebase, etc).
Setting up a Windows editor for commit messages
Setting up an external diff tool

Git & SVN

Migrating from Subversion to Git and GitHub (Slides)

Various Git Commands

  git diff           < diff of what is changed but not staged
  git diff --staged  < diff of what is staged but not committed
  git diff HEAD      < diff of the current state of the files as compared against the most recent commit
  
  git show <hash>    < diff of a specific commit
  
  git log origin/master..master             < lists unpushed commits
  git log origin/master..master --oneline
  
  
  git commit --amend  < change last commit message
  git rebase -i       < choose and mark the commit to "reword"
  
  git reset --hard HEAD  < Restore working to last committed state
  git reset --hard       < same
  git reset --hard MYTAG < Restore working to MYTAG tag reference point
  
  
  git log --stat -M                    < shows "renames" instead of deletes and adds
  
  git log --stat -C -C                 < shows "copies" if that's likely what happened
  git log --stat --find-copies-harder  < same
  
  git log -- deletedFile.txt           < find a deleted file in log history
  
  git add -u .     < Add tracked files in the staging area rather than the working tree
  git add -A .     < Add files in the working tree in addition to the staging area
  git add --all .  < same
  
  git fetch        < retrieval without merging to work in progress
  git merge        < merges what has been fetched in to working files
  git pull         < retrieval with merge into work in progress
  
  git log --graph --pretty=oneline --abbrev-commit --decorate --all -5
  
  git branch           < local branches
  git branch -r        < local remote branches
  git branch -a        < local and local remote branches
  git ls-remote origin < remote branches
  git ls-remote        < same
  
  git branch <branchname>           < create new local branch <branchname>
  git checkout <branchname>         < switch to local branch <branchname>
  git checkout -b <branchname>      < create and switch to new local branch <branchname>
  git push -u origin <branchname>   < publishes local branch to remote origin
  
  git checkout master
  git merge <branchname>  < merges local branch to checked out branch (master in this case)
  
  git stash                      < push onto a local stash stack
  git stash pop                  < pop the local stash stack
  git stash apply                < same
  git stash branch <branchname>  < create branch <branchname> from top of local stash stack
  
  git branch <branchname> THETAGNAME  < create branch <branchname> from tag THETAGNAME
  
  git config --get-regexp alias  < list aliases
  
  Alias examples:
  git config --global alias.aliases "config --get-regexp 'alias.*'"
  git config --global alias.s "status -u -s"
  git config --global alias.logfive "log --graph --pretty=oneline --abbrev-commit --decorate --all -5" 
   
  [alias]
  hist = log --pretty=format:\"%h %ad | %s%d [%an]\" --graph --date=short
  aliases = config --get-regexp \"alias.*\"
  unpushed-commits = log origin/master..master --date=\"local\" --pretty=format:\"%H %cd - %s\"
  statii = "!f() { echo \"Unpushed Commits:\"; echo; git unpushed-commits; echo; echo \"Status of Tracked Files:\"; echo; git status -uno; }; f"
  unpushed = "!f() { git log origin/$1..$1 --date=\"local\" --pretty=format:\"%H %cd - %s\"; }; f"
  pullr = "!f() { echo \"Stashing uncommitted work...\"; echo; git stash clear; git stash; echo; echo \"Pulling latest changes with rebase...\"; echo; git pull --rebase; echo; echo \"Applying previously stashed work...\"; echo; git stash apply; }; f"

Gradle Notes

Fri, 07 Sep 2012 23:47:40 -0400

Gradle Notes

Home

Mon, 01 Dec 2014 22:59:08 -0400

Home

Welcome to this wiki page powered by DokuWiki. This is a repository of notes, thoughts and information regarding various things, mostly technical and Java related. This is not a publicly editable wiki though - it is just a place I can capture info for easy access on the intertubes.

Here is a little bit about me.

General

Notes from Conferences and Symposiums - JavaOne, No Fluff Just Stuff
The Best of Technology Writing 2008
Other articles of interest - Computing, Clouds, JIRA & Confluence, SSO, CSV, Development
Data Structures And Algorithm Notes - Definitions, Q&A
ThoughtWorks Technology Radar

Seattle WingDing Notes - Notes and links for study iterations since 2008

Projects

Jenkins build-pipeline-plugin - Open Source Project I've contributed to.

Languages

Comparisons: Rosetta Code, Posters: O'Reilly - The History of Programming Languages, Levenez - Computer Languages History
Java - General Documentation, JSP and TagLibs, Hibernate, Ant Tools, Code Analyzers, Design Patterns, VM Memory, Q&A
- Spring - General Documentation, Sprint Security, Acegi
Python - General Documentation and References
Ruby - Rails, General Documentation and References
SQL - General Documentation, MySQL, Oracle, Explain Plans, Q&A
Web Based - Testing, Design, JavaScript, Ajax, CSS, HTML 5

Other

Web Services - General Documentation, SOA, ESB, Jersey, RESTEasy
Regular Expressions - General Documentation, Testing Tools and Analyzers

Platforms

Linux (also includes UNIX Notes) - Samba, SSH, VNC
Windows - Tools

Development

CVS - Quick Reference, Branching, Diffs
Git - General Documentation and References
Maven - Public Repos, pom.xml, Build Phases, Common Commands
Gradle - Documentation and References

Wiki

DokuWiki Notes - Information about syntax for using installed plugins

Java Notes

Mon, 06 Jun 2022 00:34:31 -0400

Java Notes

General Documentation

The Java Tutorials
Collected Java Practices - Concise presentations of Java practices, tasks, and designs, illustrated with syntax-highlighted code examples.
Java2s.com - Programming tutorials and source code examples
Java's new math, Part 2: Floating-point numbers
Java Performance Tuning Tips November 2008
Essential Java resources: A comprehensive listing of must-have books, sites, blogs, events, and more
Everything about Java 8

JSP and TagLibs

Jakarta Project: XTags Library

JPA

Has JPA Killed the DAO?

Hibernate

Hibernate Performance and Scalability Out of the Box (Webcast recording)

Ant Tools

Apache Ant User Manual

ASCII Art

Text Ascii Art Generator

Build Visualization

These all use Graphviz to render graphics from generated .dot files.

Code Analyzers

Design Patterns

The Net Objectives Design Patterns Repository

VM Memory Management

Questions and Topics

Q. Is Java Pass by Value or Pass by Reference? (See also: http://www.youtube.com/watch?v=dk3Iiqof6jA)

With primitives it is simple pass by value.  
Objects references are passed by value.

Q. Composition vs. Aggregation

Aggregation is a specialization of association, specifying a whole-part relationship between two objects. Composition is a stronger form of
aggregation where the whole and parts have coincident lifetimes, and it is very common for the whole to manage the lifecycle of its parts.

Q. What's the difference between using synchronized on a method or in a block?

The main difference is that if you use a synchronized block you may lock on an object other than "this" which is a more flexible approach.

Q. Threads

Q. What is the Java volatile keyword?

Essentially, volatile is used to indicate that a variable's value will be modified by different threads.
Declaring a volatile Java variable means:
- The value of this variable will never be cached thread-locally: all reads and writes will go straight to "main memory";
- Access to the variable acts as though it is enclosed in a synchronized block, synchronized on itself.

Q. When would you use non-public modifiers on a class?

To make an inner class private.

Q. Set vs. List vs. Map

A Set is a collection that has no duplicate elements.
A List is a collection that has an order associated with its elements.
A Map is a way of storing key/value pairs. A Map is similar to two-column table.

Q. What are the benefits of immutable objects? (From Brian Goetz: To mutate or not to mutate?)

Immutable classes, when used properly, can greatly simplify programming. They can only be in one state, so as long as they are properly 
constructed, they can never get into an inconsistent state. You can freely share and cache references to immutable objects without having 
to copy or clone them; you can cache their fields or the results of their methods without worrying about the values becoming stale or 
inconsistent with the rest of the object's state. Immutable classes generally make the best map keys. And they are inherently thread-safe, 
so you don't have to synchronize access to them across threads.

Q. How do you make a class immutable? (See also...)

> Ensure the class cannot be overridden - make the class final, or use static factories and keep constructors private.
> Make the fields private and final.
> Force callers to construct an object completely in a single step, instead of using a no-argument constructor combined with subsequent calls to setXXX methods (that is, avoid the Java Beans convention).
> Do not provide any methods which can change the state of the object in any way - not just setXXX methods, but any method which can change state.
> If the class has any mutable object fields, then they must be defensively copied when passed between the class and its caller.

Q. Statements vs. PreparedStatements

Prepared statements make formatting a non-issue, adds some security against SQL injection, and are pre-compiled.

Q. Comparators and Sorting

Q. SAX (push), DOM, StAX (pull)

JavaOne 2008 Notes

Tue, 23 Sep 2008 18:39:28 -0400

JavaOne 2008 Notes

JavaOne Web Site - All the keynotes (recommended: Sun General Sessions from Tuesday afternoon, May 6th - Java Technical Roadmap Overview, and Friday, May 9th - Cool Stuff with Java), and access to Technical Session Pdfs and Multimedia.

Stuff of Interest...?

Testing Coverage Tools

Cobertura - Cobertura is a free Java tool that calculates the percentage of code accessed by tests. It can be used to identify which parts of your Java program are lacking test coverage. It is based on jcoverage.
EclEmma - EclEmma is a free Java code coverage tool for Eclipse, available under the Eclipse Public License. Internally it is based on the EMMA Java code coverage tool, trying to adopt EMMA's philosophy for the Eclipse workbench.
EMMA- EMMA is an open-source toolkit for measuring and reporting Java code coverage. EMMA distinguishes itself from other tools by going after a unique feature combination: support for large-scale enterprise software development while keeping individual developer's work fast and iterative.
Crap4j - Crap4j is a Java implementation of the CRAP (Change Risk Analysis and Predictions) software metric – a mildly offensive metric name to help protect you from truly offensive code.

Testing APIs

JUnit 4.x - JUnit is a simple framework for writing and running automated tests. Version 4 expands and simplifies with Annotations.
TestNG - TestNG is a testing framework inspired from JUnit and NUnit but introducing some new functionalities that make it more powerful and easier to use.

Continuous Integration

Hudson - Hudson monitors executions of repeated jobs, such as building a software project or jobs run by cron. In a nutshell, Hudson provides an easy-to-use so-called continuous integration system, making it easier for developers to integrate changes to the project, and making it easier for users to obtain a fresh build. It also provides for monitoring the execution of externally-run jobs, such as cron jobs and procmail jobs, even those that are run on a remote machine.
Continuum - Continuum is a continuous integration server for building Java based projects.

Automated Code Quality Tools

CheckStyle - Checkstyle is a development tool to help programmers write Java code that adheres to a coding standard. It automates the process of checking Java code to spare humans of this boring (but important) task. This makes it ideal for projects that want to enforce a coding standard.
PMD - PMD scans Java source code and looks for potential problems.
Findbugs - FindBugs is a program that uses static analysis to look for bugs in Java code.

Automated Documentation

UMLGraph - UMLGraph allows the declarative specification and drawing of UML class and sequence diagrams. The UMLGraphDoc doclet automatically adds UML diagrams to JavaDoc documentation.
DocWeb - DocWeb is a set of servlets that are essentially equivalent to the JavaDoc tool that is distributed with the JDK. The key difference is that it is designed to be internationalized cooperatively by the community.

Debug Tools

mpstat - Report processors related statistics.
vmstat - Report virtual memory statistics.
iostat - Report CPU statistics and input/output statistics for devices and partitions.
Charles - Charles is a Web debugging tool, HTTP monitor, and reverse HTTP proxy for Web developers that includes plain text debugging of HTTPS/SSL. It is built in Java Swing, and runs on all Java platforms. It is an HTTP proxy server that displays requests and responses, complete with HTTP headers. This enables the developer to examine the exact content of HTTP exchanges, including cookies, caching, and redirects. It can also throttle your connection in order to simulate modem conditions. It is a valuable tool for all Web developers and is especially useful for debugging XML RCP, SOAP, Web services, AJAX/XMLHTTP, and Macromedia Flash client-server traffic including AMF, AMF 3, LoadVars, and XML Sockets.

Security Tools

Nikto - Nikto is an Open Source (GPL) web server scanner which performs comprehensive tests against web servers for multiple items, including over 3500 potentially dangerous files/CGIs, versions on over 900 servers, and version specific problems on over 250 servers. Scan items and plugins are frequently updated and can be automatically updated (if desired).

Web Sites

The Daily WTF - Curious Perversions in Information Technology

Dynamic Scripting Languages

Groovy - Groovy is like a super version of Java. It can leverage Java's enterprise capabilities but also has cool productivity features like closures, builders and dynamic typing.
- is an agile and dynamic language for the Java Virtual Machine
- builds upon the strengths of Java but has additional power features inspired by languages like Python, Ruby and Smalltalk
- makes modern programming features available to Java developers with almost-zero learning curve
- supports Domain-Specific Languages and other compact syntax so your code becomes easy to read and maintain
- makes writing shell and build scripts easy with its powerful processing primitives, OO abilities and an Ant DSL
- increases developer productivity by reducing scaffolding code when developing web, GUI, database or console applications
- simplifies testing by supporting unit testing and mocking out-of-the-box
- seamlessly integrates with all existing Java objects and libraries
- compiles straight to Java bytecode so you can use it anywhere you can use Java
- Also see: Grails - Grails aims to bring the “coding by convention” paradigm to Groovy. It's an open-source web application framework that leverages the Groovy language and complements Java Web development. You can use Grails as a standalone development environment that hides all configuration details or integrate your Java business logic.
JRuby - JRuby is an 100% pure-Java implementation of the Ruby programming language.
- A 1.8.6 compatible Ruby interpreter written in 100% pure Java
- Most builtin Ruby classes provided
- Support for interacting with and defining java classes from within ruby
- Bean Scripting Framework (BSF) support
- Distributed under a tri-license (CPL/GPL/LGPL)
Jython - Jython is an implementation of the high-level, dynamic, object-oriented language Python seamlessly integrated with the Java platform. The predecessor to Jython, JPython, is certified as 100% Pure Java. Jython is freely available for both commercial and non-commercial use and is distributed with source code. Jython is complementary to Java and is especially suited for the following tasks:
- Embedded scripting - Java programmers can add the Jython libraries to their system to allow end users to write simple or complicated scripts that add functionality to the application.
- Interactive experimentation - Jython provides an interactive interpreter that can be used to interact with Java packages or with running Java applications. This allows programmers to experiment and debug any Java system using Jython.
- Rapid application development - Python programs are typically 2-10X shorter than the equivalent Java program. This translates directly to increased programmer productivity. The seamless interaction between Python and Java allows developers to freely mix the two languages both during development and in shipping products.
- Dynamic compilation to Java bytecodes - leads to highest possible performance without sacrificing interactivity.
- Ability to extend existing Java classes in Jython - allows effective use of abstract classes.
- Optional static compilation - allows creation of applets, servlets, beans, …
- Bean Properties - make use of Java packages much easier.
- Python Language - combines remarkable power with very clear syntax. It also supports a full object-oriented programming model which makes it a natural fit for Java's OO design.
Scala - Scala is a general purpose programming language designed to express common programming patterns in a concise, elegant, and type-safe way. It smoothly integrates features of object-oriented and functional languages. It is also fully interoperable with Java.
- Scala is a pure object-oriented language in the sense that every value is an object. Types and behavior of objects are described by classes and traits. Class abstractions are extended by subclassing and a flexible mixin-based composition mechanism as a clean replacement for multiple inheritance.
- Scala is also a functional language in the sense that every function is a value. Scala provides a lightweight syntax for defining anonymous functions, it supports higher-order functions, it allows functions to be nested, and supports currying. Scala's case classes and its built-in support for pattern matching model algebraic types used in many functional programming languages.
- Furthermore, Scala's notion of pattern matching naturally extends to the processing of XML data with the help of right-ignoring sequence patterns. In this context, sequence comprehensions are useful for formulating queries. These features make Scala ideal for developing applications like web services (external link).
- Scala is equipped with an expressive type system that enforces statically that abstractions are used in a safe and coherent manner.
- Scala provides a unique combination of language mechanisms that make it easy to smoothly add new language constructs in form of libraries.
- Scala is designed to interoperate well with popular programming environments like the Java 2 Runtime Environment (JRE) and the .NET Framework (CLR). In particular, the interaction with mainstream object-oriented languages like Java and C# is as smooth as possible. Scala has the same compilation model (separate compilation, dynamic class loading) like Java and C# and allows access to thousands of high-quality libraries.

Ajax JavaScript Libraries

jQuery User Interface - jQuery UI is a set of themable widgets and interactions, built on top of the jQuery JavaScript Library, that you can use to build highly interactive web applications.
ExtJS - Ext JS is a cross-browser JavaScript library for building rich internet applications.
dijit - Skinnable, template-driven widgets with accessibility and localization built right in—the way you want it. From accordions to tabs, we have you covered.
script.aculo.us - script.aculo.us provides you with easy-to-use, cross-browser user interface JavaScript libraries to make your web sites and web applications fly.
Google Gears - Google Gears is an open source project that enables more powerful web applications, by adding new features to your web browser, such as worker pools to mimic threading in JavaScript.
Mozilla Prism - Prism is an application that lets users split web applications out of their browser and run them directly on their desktop.
Adobe Air - The Adobe AIR runtime lets developers use proven web technologies to build rich Internet applications that deploy to the desktop and run across operating systems.
Aptana Jaxer - Jaxer is the world's first true Ajax server. HTML, JavaScript, and CSS are native to Jaxer, as are XMLHttpRequests, JSON, DOM scripting, etc. And as a server it offers access to databases, files, and networking, as well as logging, process management, scalability, security, integration APIs, and extensibility.

The Buzz

Glassfish - GlassFish is a free, open source application server which implements the newest features in the Java EE 5 platform. The Java EE 5 platform includes the latest versions of technologies such as such as JavaServer Pages(JSP) 2.1, JavaServer Faces(JSF) 1.2, Servlet 2.5, Enterprise JavaBeans 3.0, Java API for Web Services(JAX-WS) 2.0, Java Architecture for XML Binding(JAXB) 2.0, Web Services Metadata for the Java Platform 1.0, and many other new technologies.
JavaFx - JavaFX is a powerful client technology for creating rich Internet applications.

Cloud Computing

Amazon EC2 - Amazon EC2 presents a true virtual computing environment, allowing you to use web service interfaces to requisition machines for use, load them with your custom application environment, manage your network's access permissions, and run your image using as many or few systems as you desire.
Google App Engine - Google App Engine enables you to build web applications on the same scalable systems that power Google applications.
Aptana Cloud - Aptana Cloud is a scalable Elastic Application Cloud featuring the most popular and widely adopted Web infrastructure, ready to use and ready to scale as you need it. Aptana Cloud also plugs right into your IDE to provide instant deployment, smart synchronization, and seamless migration as you scale. Aptana Cloud is ideal for developers who use scripting languages to create Ajax, Facebook, mySpace and all other sorts of Web applications.

Linux Notes

Sat, 14 Mar 2020 17:29:13 -0400

Linux Notes

General Documentation

Unix

Unix Toolbox - A collection of useful Unix/Linux/BSD commands and tasks
Solaris QuickSheet
Sunfreeware - Free and Open Source Software (FOSS) for Sun Microsystem's Solaris

Samba

Samba can be installed by running:

 apt-get install samba

Samba allows you to share a directory on your Linux filesystem with your Windows machine. In the /etc/samba directory, there is an smb.conf.user file that is used for any Samba extensions that you'd like to make to share additional directories. By default, you should have your home directory set up as a samba share in smb.conf. It's in there as the [homes] clause, but the actual share name is the same as your username (ex. \\mylinuxservername\dkirkdorffer). If you are connecting for the first time, you will have to set the samba password using following command:

 sudo smbpasswd -a dkirkdorffer

You will be prompted to enter a new password; this will be the password to use when connecting to your Linux box from your Windows box.

 [dkirkdorffer]
    path = /home/dkirkdorffer
    read only = no
    valid users = dkirkdorffer
    create mask = 0644
    browsable = no

If you want to have access to the root of your linux drive, you can edit the /etc/samba/smb.conf.user file and add this snippet (modify the username to your username):

 [root]
    path = /
    read only = no
    valid users = dkirkdorffer
    create mask = 0644
    browsable = no

This will enable you to access the root of your linux drive using the alias “root” (ex: \\mylinuxservername\root)

Start (or stop and restart) the smbd daemon (at /usr/sbin or possibly at /etc/init.d) like so:

 /usr/sbin/smbd start
 
 /usr/sbin/smbd stop
 
 /usr/sbin/smbd restart

For troubleshooting info read the ”The Samba Checklist”.

To determine the IP address of the Samba server run:

nmblookup -B BIGSERVER __SAMBA__

UNIX

Additional UNIX resources of use:

Enabling and configuring SAMBA as shipped with Solaris 10 or SAMBA and SWAT in Solaris 10 Update 4 (Solaris 10 8/07).

Start and stop alternatives:

 /usr/sfw/sbin/smbd start
 
 /usr/sfw/sbin/smbd stop
 
 /usr/sfw/sbin/smbd restart

 svcadm enable samba wins
 
 svcadm disable samba wins

SSH

How to set up SSH keys - i.e. generate the keys on the server (UNIX, Linux, BSD etc.) instead of the client (i.e. in Windows).
Special instructions for Cervisia - Before doing a check-out for the first time, make sure that the key for the CVS server is in your .ssh/known_hosts file. One way to do this is: 'ssh <user>@<cvs_hostname>'. Failing to do this will make Cervisia ask for a password and then terminate the checkout with the error “Host key verification failed”.

VNC

You can start the VNC Server by running ./startvnc.sh or ./startvnc4.sh. VNC Viewer can then be installed on your Windows system, allowing you full access to your Linux system from Windows (or another Linux system). You can override the default geometry of the VNC window created by the server by altering the shell script like this:

 #!/bin/sh
 vncserver -geometry 1580x1100 -depth 24
 nohup vncconfig -nowin > /dev/null 2>&1 &

 #!/bin/sh
 /usr/bin/vnc4server -geometry 1220x830 -depth 24
 nohup /usr/bin/vnc4config -nowin > /dev/null 2>&1 &

An .vnc/xstartup file is also used and if using KDE can be setup as so

 #!/bin/sh
 vncconfig -nowin &
 startkde &

Set the password by running vncpasswd, vnc4passwd or tightvncpasswd, depending on your version of VNC.

The default starting port for VNC is 5901 (or 5801 through a web browser), additional instances of VNC will increment this number by 1 (so 5902 for the second one). You can find what port it's currently running on by running:

 ps -ef | grep vnc

and looking for the ”rfbport” parameter. Alternatively, look in the ~/.vnc directory at the log file.

TightVNC and RealVNC are both provide good client viewers, and VNC servers.

UNIX

See: VNC on Solaris

On Solaris, the ./startvnc.sh might look like this:

 #!/bin/ksh
 PATH=$PATH:/usr/dt/bin:/usr/openwin/bin:/usr/X11/bin
 cd ~
 vncserver -depth 24 -geometry 1500x768 :1

./killvnc.sh might look like this:

 #!/bin/ksh
 PATH=$PATH:/usr/dt/bin:/usr/openwin/bin:/usr/X11/bin
 cd ~
 vncserver -kill :1

and the .vnc/xstartup file might look like this:

 #!/bin/sh
 [ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
 xsetroot -solid grey
 vncconfig -iconic &
 xterm -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
 gnome-session &

Maven Notes

Thu, 21 Oct 2021 03:31:32 -0400

Maven Notes

General

Searchable Public Repositories

http://repo1.maven.org/maven2/ - Default Maven Repository

pom.xml

Introduction to the POM
Project Descriptor Reference - A reference for the Maven project descriptor used in Maven

Build Phases

Build lifecycles are defined by a different list of build phases, wherein a build phase represents a stage in the lifecycle. The default lifecycle has the following build phases:

validate - validate the project is correct and all necessary information is available
compile - compile the source code of the project
test - test the compiled source code using a suitable unit testing framework. These tests should not require the code be packaged or deployed
package - take the compiled code and package it in its distributable format, such as a JAR.
integration-test - process and deploy the package if necessary into an environment where integration tests can be run
verify - run any checks to verify the package is valid and meets quality criteria
install - install the package into the local repository, for use as a dependency in other projects locally
deploy - done in an integration or release environment, copies the final package to the remote repository for sharing with other developers and projects.

Common Commands

mvn archetype:create
-DarchetypeGroupId=org.apache.maven.archetypes
-DarchetypeArtifactId=maven-archetype-webapp
-DgroupId=com.mycompany.app
-DartifactId=my-webapp
mvn compile
mvn test
mvn test-compile
mvn package
mvn install
mvn site
mvn clean
mvn eclipse:eclipse
mvn process-resources

No Fluff Just Stuff - September 2008 Notes

Fri, 26 Sep 2008 14:59:56 -0400

No Fluff Just Stuff - September 2008 Notes

This builds on top of JavaOne 2008 Notes previously attended.

No Fluff Just Stuff site.

Suggested Books / Reading

Stuart Halloway's multi-part blog series comparing Clojure, Groovy, JRuby, and Scala:

Languages

Clojure - Clojure is a dialect of Lisp that runs on the Java Virtual Machine. It is a general purpose language sporting interactive development, and it encourages a functional programming style that enables simplified multithreaded programming. Clojure honors the code-as-data philosophy and has a sophisticated Macro system with features such as automatic gensyms.
Erlang - Erlang is a programming language which has many features more commonly associated with an operating system than with a programming language: concurrent processes, scheduling, memory management, distribution, networking, etc.
Fan - Fan is a general purpose object-oriented programming language that runs on both JRE and .NET CLR. The language is also a functional programming language in the sense that it supports functions as first-class objects. Concurrency is supported by implementing the Actor Model as used by Erlang. Fan uses static typing but has also support for dynamic typing. Fan uses a curly brace syntax similar to C# and Java.

Groovy

Groovy home page
Groovy JDK API Specification - Javadoc documentation of the methods added to the JDK to make it more groovy.
Groovy 1.5 API

Grails

Grails home page
Versions:
- 1.0.3 - Now (Sept 2008)
- 1.0.4 - October 2008
- 1.1 - End of 2008 (See roadmap)

Regular Expressions

QuickREx - Regex Tester Eclipse plugin. Also has a standalone app.
Regex - Eclipse Regular Expression Tester

Google Web Toolkit

Google Web Toolkit home page
GWT Designer - GWT Designer™ is a GUI creator that supports GWT. Use GWT Designer's visual tools and wizards, and Java code will be generated for you. You don't need to write any lines of Java code, but you can fully edit the resulting Java if you wish.
Google Web Toolkit Solutions - David Geary book site.
dotemplate.com - Quick HTML templates with CSS.

Open Source Tools

For a list of hundreds of open source Java tools go to Java-Source.net.

Build Systems

For more tools than the ones listed below go to Java-Source.net.

Ivy - Ivy is a free java based dependency manager, with powerful features such as transitive dependencies, ant integration, maven repository compatibility, continuous integration, html reports and many more.

Code Analyzers

For more tools than the ones listed below go to Java-Source.net.

PMD/CPD - PMD scans Java source code and looks for potential problems. Includes a copy+paste code detector.
JLint - Jlint will check your Java code and find bugs, inconsistencies and synchronization problems by doing data flow analysis and building the lock graph.
Condenser - Condenser is a tool for finding and removing duplicated Java code. Unlike tools that only locate duplicated code, the aim of Condenser is to also automatically remove duplicated code where it is safe to do so.
QJ-Pro - Developers can automatically inspect their Java source code and improve their Java programming skills as they write their programs. QJ-Pro provides descriptive Java patterns explaining error prone code constructs and providing solutions for it.
Hammurapi - Hammurapi 5 is a versatile automated code review solution. It allows you to establish code governance processes in your organization by injecting automated code review “hooks” into development and build processes.
JDepend - JDepend traverses Java class file directories and generates design quality metrics for each Java package. JDepend allows you to automatically measure the quality of a design in terms of its extensibility, reusability, and maintainability to manage package dependencies effectively.
JarAnalyzer - JarAnalyzer is a dependency management utility for jar files. It's primary purpose is to traverse through a directory, parse each of the jar files in that directory, and identify the dependencies between the jar files. The output is an xml file representing the PhysicalDependencies between the jar files.
Macker - Macker is a build-time architectural rule checking utility for Java developers. It's meant to model the architectural ideals programmers always dream up for their projects, and then break – it helps keep code clean and consistent. You can tailor a rules file to suit a specific project's structure, or write some general “good practice” rules for your code. Macker doesn't try to shove anybody else's rules down your throat; it's flexible, and writing a rules file is part of the development process for each unique project.
JavaNCSS - JavaNCSS is a simple command line utility which measures two standard source code metrics for the Java programming language. The metrics are collected globally, for each class and/or for each function.
DoctorJ - Beyond the level of what Javadoc does, DoctorJ compares documentation against code.
XRadar - The XRadar is an open extensible code report tool currently supporting all Java based systems.
diffj - DiffJ is a command-line program based on diff (from Unix), but is designed specifically for Java code. It compares only Java source code, not whitespace nor comments. It also handles reorganization of Java code, so that, for example, methods that have been moved within the same class – but have not otherwise changed – are not considered to be different.
Jupiter - Jupiter is an Eclipse IDE Plug-In for doing code reviews.

Python Notes

Thu, 29 Jan 2009 16:26:25 -0400

Python Notes

General Documentation

Additional References

Biased towards Python, but see the strong vs. weak section at the end: http://www.ferg.org/projects/python_java_side-by-side.html
side by side attempt to point out equivalents and differences: http://www.razorvine.net/python/PythonComparedToJava
dive into Python: http://www.diveintopython.org/
Wing IDE (not free): http://www.wingware.com/products
Python plugin for Eclipse: http://pydev.sourceforge.net/
pycrust - enhanced shell, with some completion

Regular Expressions

Wed, 01 Dec 2010 22:52:40 -0400

Regular Expressions

General Documentation

The Premier website about Regular Expressions

Testing Regular Expressions

RegexPlanet: Regular Expression Test Page (Java)

Regular Expressions Analyzers

strfriend - Visualize regular expressions simply
Regular Expression Analyzer (Java, JavaScript, Perl)
YAPE::Regex::Explain Module (Perl)
- Further info on usage.
- CPAN
- Command line example: perl -MYAPE::Regex::Explain -e "print YAPE::Regex::Explain->new(qr/(\d+)/)->explain;"

Ruby Notes

Sun, 08 May 2011 02:57:22 -0400

Ruby Notes

General Documentation

Ruby Tutorials

Try Ruby! - Online Tutorial
Ruby Koans - Teaching tests
Ruby From Other Languages

Ruby on Rails

Ruby on Rails: Documentation
Rails Wiki
Rails 3 Cheat Sheets (PDF)
Rails ActiveRecord Data Type Mappings (PDF)
Rails ActiveRecord Associations (PDF)

P2PU
- Introduction to Ruby and Rails
- Resources:
  - Andy Lindeman's Blog - Instructor's Blog
  - BalWiki - Student run wiki of course related resources
- Course Instructor/Student Interaction Tools:
  - p2pu-rubyrails-jan2011 Google Group
  - irc.freenode.net#p2pu-rubyrails
  - Public Pad: p2pu-rubyrails
  - BigBlueButton Shared Meeting
  - join.me - Another free screen sharing tool
  - Screencast-O-Matic - Screen recorder
- Code Tools:
  - dankirkd/coursework - GitHub
  - Gist - GitHub - For posting code snippets
- Project Hosting
  - Heroku - Cloud application platform for Ruby (Docs)
  - localhost - Running on my local Vagrant VM
- Course Syllabus:
- Course Apps:
  - P2PU Introduction to Ruby and Rails Blog
  - Ribbet! (A P2PU Introduction to Ruby and Rails App)
VM Environment:
- Vagrant: Getting Started - Virtual Machine
- VirtualBox - Virtualization Environment
- VirtualBox User Manual (PDF)

Spring Notes

Tue, 30 Apr 2013 19:54:57 -0400

Spring Notes

SQL Notes

Thu, 02 May 2013 19:35:06 -0400

SQL Notes

Oracle Technology Network
Oracle Database Express Edition Online Documentation 10g Release 2 (10.2)
SQL*Plus Set Commands
Oracle 10g Data Pump (Advanced Exports and Imports)

Explain Plans

Producing and Reading Explain Plans

To produce an Explain Plan:

explain plan set statement_id = '<SOME_IDENTIFIER>' for
/* ------ Your SQL here ------ */

To read an Explain Plan:

select operation, options, object_name
from plan_table
where statement_id = '<SOME_IDENTIFIER>'
start with id = 0
connect by prior id=parent_id and prior statement_id = statement_id;

Questions and Topics

Q. How can you find an orphan row in a join?

Do a Left Join (= Left Outer Join) and look for nulls.

select * 
from TABLE_A
  left outer join TABLE_B
    on TABLE_A.NAME = TABLE_B.NAME 
where TABLE_B.ID is null

Home

Sat, 21 Feb 2009 04:10:07 -0400

Home

Here is a little bit about me.

Notes from conferences and symposiums
The Best of Technology Writing 2008
Other articles of interest
Python Notes
SQL Notes
Regular Expressions
Linux Notes
Seattle WingDing Notes
DokuWiki Notes (Includes information about syntax for using installed plugins)

Web Notes

Wed, 22 Jun 2016 17:58:54 -0400

Web Notes

General

Testing

Browser Sandbox - Run any browser from the web - Supports testing of pages on various browsers via a plug-in.

Design

Nifty Color Scheme Designer tool
Useful Generate It online tools (Mod Rewrite, Favicons, Rounded Corners, CSS Layout, etc…)

JavaScript

Douglas Crockford on Javascript - 5 video presentations (and others) about JavaScript
Douglas Crockford: "Advanced JavaScript" - 3 video presentations
jconsole - Web-based interactive JavaScript shell

jQuery and YUI 3: A Tale of Two JavaScript Libraries

JQuery

Ajax

Ajax Mistakes

CSS

Browser Specific Syntax Rules Support (Chart)
CSS Compatibility and Internet Explorer (IE 5 through IE 8)
The CSS Position Property

HTML 5

Video: Introduction to HTML 5 - Brad Neuberg (Developer Programs, Google), Slides (PDF) - Oct, 2009
Modernizr - HTML 5 Support Detector Library
The HTML5 test - How well does your browser support HTML5?
HTML 5 Outliner

Flash MP3 Player

Google Search Result Links

Web Services Notes

Mon, 06 Jun 2022 01:33:33 -0400

Web Services Notes

General Documentation

The Java Web Services Tutorial (Java Web Services Developer Pack (JWSDP) 2.0) - February, 2006
Classification of HTTP APIs

REST

HTTP

Hypertext Transfer Protocol -- HTTP/1.1

Methods

Idempotent - no matter how many times you apply the operation, the result is always the same.
Safe - the operation does not change the state of the resource representation.

GET - Idempotent, safe
PUT (Update) - Idempotent
POST (Create) - Not idempotent, not safe
DELETE - Idempotent

Resources

Architectural Styles and the Design of Network-based Software Architectures - Roy T. Fielding's dissertation.
InfoQ: A Brief Introduction to REST
An Introduction to REST (Video)
InfoQ: How to GET a Cup of Coffee - A case study
REST in Practice (Book)

JAX-RS & Jersey

JAX-RS: Java™ API for RESTful Web Services (v1.1) - September, 2009
Jersey - JAX-RS (JSR 311) Reference Implementation

RESTEasy

RESTEasy - A JBoss framework for writing RESTful web services
RESTEasy JAX-RS Documentation
Develop Restful application with RESTeasy (Tutorial)

AtomPub

The Atom Publishing Protocol (RFC 5023)
AtomServer - A generic data store implemented as a RESTful web service.
Apache Abdera - A functionally-complete, high-performance implementation of the IETF Atom Syndication Format (RFC 4287) and Atom Publishing Protocol (RFC 5023) specifications.
atomojo - An Atom Publishing Protocol Client & Server
“Getting to know the Atom Publishing Protocol” developerWorks Article:

SOA / ESB

Patterns and Best Practices for Enterprise Integration
Top Open Source ESB Projects
Best-of-Breed ESBs
InfoQ: Does My Bus Look Big in This? - SOA without ESB presentation by Martin Fowler and Jim Webber

Open Source ESB

Windows Notes

Sat, 16 Nov 2013 20:08:37 -0400

Windows Notes

Tools

Junction - Create Win2K NTFS symbolic links.
GnuWin32

Forfiles

Example:

forfiles -D-1 -PC:\Windows\temp -Manon* -C"cmd /c if @ISDIR==TRUE rd /q /s @FILE"
forfiles -D-1 -PC:\DOCUME~1\atg\LOCALS~1\Temp -Manon* -C"cmd /c if @ISDIR==TRUE rd /q /s @FILE"
forfiles -D-3 -PC:\Windows\temp -Mhudson-remoting* -C"cmd /c if @ISDIR==TRUE rd /q /s @FILE"
forfiles -D-3 -PC:\DOCUME~1\atg\LOCALS~1\Temp -Mhudson-remoting* -C"cmd /c if @ISDIR==TRUE rd /q /s @FILE"