Friday, December 19, 2008

Tri-State Checkbox using Javascript

Recently I noticed how yahoo mail select all check box only shows two
states while selecting/un-selecting mails to perform various actions.
So I decided to experiment and create a simple tri-state check box that could display my intermediate state. Below is what I ended up with:

Tri-State Checkbox Demo with dependent checkboxes

Select/Unselect All

It's really simple to use. Here's what you have to do:
  1. Include the javascript file in your html
  2. Have a place-holder node (span in my case) to hold the image for the tri-state box
  3. Place the related checkboxes inside a container, e.g. a div
  4. Invoke the initTriStateCheckBox(<place holder id>, <container id>, false) function in your html

Standalone Tri-State Checkbox Demo

I liked this

Here's what you have to do to create a standalone one:
  1. Include the javascript file in your html
  2. Have a place-holder node (span in my case) to hold the image for the tri-state box
  3. Create a hidden field to hold the state of the box
  4. Invoke the initTriStateCheckBox(<place holder id>, <hidden field id>, true) function in your html

The zip file containing the javascript, images and a sample is available here. It is also a GitHub project set up by Michal Letynski.


Sunday, July 13, 2008

Threaded Comments in Blogger

With all the new features being introduced in blogger, there was still a feature I would like which was not included - Threaded Comments. So I decided to mix the existing comment system with a little bit of javascript and come up with my own version of threaded comments. The advantage of using this is that you are still allowing blogger
to manage your comments unlike a couple of other tools I have seen. Check out the Threaded version in action
by adding your comments below ;).

The idea behind this came from the simple observation that most of us use @AuthorName to reply to comments posted by other users in 'single' threaded comments. So the javascript I wrote just parses the comment bodies for this author name (or comment ids) and then searches for appropriate comments to find parents of the reply comments.

Below is an image of how after I implemented this idea the comments section on my blog changed:

In addition to the threaded support:

  • Include multiple replies in your comment using multiple @replyTargets on separate lines in your comment
  • Blog authors can have their comments highlightd differently - use css styles for 'blog-author-comment' and 'blog-nonauthor-comment'
  • Include multiple replies in your comment using multiple @replyTargets in the comment
  • Hide/Show individual comments
  • Configurable template to display comments - use you custom template to call applyCommentTemplate();

How to install:
Note: Remember to back up your existing template before making any changes to it.
Here are the steps to follow:

  1. Include the java script file to the top of your template just before the <b:skin> tags starts

    <script type="text/javascript">
    --- Threaded Comments ---
    v 0.9.3 15th March 2009
    By Shams Mahmood
    function Author(C,A,B){;;this.url=B;this.toString=function(F){var E="\t";if(F){for(var D=0;D<F;D++){E+="\t"}}return"Author[\n"+E+"id="", \n"+E+"name="", \n"+E+"url="+this.url+"\n"+E+"]"}}function Comment(E,H,G,C,B,D,F,A){;this.sequenceNumber=H;this.postedTime=G;this.body=F;this.deleted=A;this.deleteUrl=B;this.deleteText=D;this.parentId="";this.children=new Array();this.level=0;;this.getChildCount=function(){return this.children.length};this.addChild=function(I){this.children[this.getChildCount()];;I.level=this.level+1};this.toString=function(K){var J="\t";if(K){for(var I=0;I<K;I++){J+="\t"}}return"Comment[\n"+J+"id="", \n"+J+"sequence="+this.sequenceNumber+", \n"+J+"deleted="+this.deleted+", \n"+J+"parentId="+this.parentId+", \n"+J+"children=["+this.children+"], \n"+J+"level="+this.level+", \n"+J+"author="", \n"+J+"posted time="+this.postedTime+", \n"+J+"body="+this.body+"\n"+J+"]"}}function trimBrsFromString(C){var F=trimString(C);var B=["<br>","<br >","<br/>","<br />","<BR>","<BR >","<BR/>","<BR />"];if(F){var E=true;while(E){E=false;for(var D in B){var A=B[D];if(F.indexOf(A)==0){F=F.substring(A.length);F=trimString(F);E=true}var H=F.length;var G=F.lastIndexOf(A);if(G>=0&&G==H-A.length){F=F.substring(0,G);F=trimString(F);E=true}}}}return F}function trimString(A){var E="";if(A){var D=false;for(var B=0;B<A.length;B++){var F=A.charAt(B);if(!D&&F!=" "&&F!="\n"&&F!="\t"){D=true}if(D){E+=F}}D=false;var C=-1;for(var B=E.length-1;!D&&B>0;B--){var F=E.charAt(B);if(!D&&F!=" "&&F!="\n"&&F!="\t"){D=true;C=B}}if(C>0){E=E.substring(0,C+1)}}return E}function addItem(A,B){A[]=B}function getAllItems(C){var D=new Array();var B=0;for(var A in C){D[B]=C[A];B++}return D}function getItemsCount(C){var B=0;for(var A in C){B++}return B}var ALL_AUTHORS=new Object();var ALL_COMMENTS=new Object();function getNewAuthorId(){var C=1;for(var A in ALL_AUTHORS){if(ALL_AUTHORS[A]&&ALL_AUTHORS[A].id){var B=ALL_AUTHORS[A].id;if(B>=C){C=B+1}}}return C}function createAuthor(C,A,B){return new Author(C,A,B)}function addAuthor(A){addItem(ALL_AUTHORS,A)}function getAllAuthors(){return getAllItems(ALL_AUTHORS)}function getAuthorsCount(){return getItemsCount(ALL_AUTHORS)}function findAuthor(C,B){for(var A in ALL_AUTHORS){if(ALL_AUTHORS[A]){if(ALL_AUTHORS[A].name==C&&ALL_AUTHORS[A].url==B){return ALL_AUTHORS[A]}}}return null}function getNewCommentSequence(){var C=1;for(var A in ALL_COMMENTS){if(ALL_COMMENTS[A]&&ALL_COMMENTS[A].sequenceNumber){var B=ALL_COMMENTS[A].sequenceNumber;if(B>=C){C=B+1}}}return C}function createComment(E,H,G,C,B,D,F,A){return new Comment(E,H,G,C,B,D,F,A)}function addComment(A){addItem(ALL_COMMENTS,A)}function getAllComments(){return getAllItems(ALL_COMMENTS)}function getRootComments(){var D=new Array();var C=0;for(var A in ALL_COMMENTS){var B=ALL_COMMENTS[A];if(B&&B.level==0){D[C]=B;C++}}return D}function getCommentsCount(){return getItemsCount(ALL_COMMENTS)}function findComment(B){for(var A in ALL_COMMENTS){if(ALL_COMMENTS[A]){if(ALL_COMMENTS[A].id==B){return ALL_COMMENTS[A]}}}return null}function findLastCommentByAuthorName(C){var B=null;for(var A in ALL_COMMENTS){if(ALL_COMMENTS[A]){if(ALL_COMMENTS[A]{B=ALL_COMMENTS[A]}}}return B}function findLastCommentByPartialAuthorName(C){var B=null;for(var A in ALL_COMMENTS){if(ALL_COMMENTS[A]){if(ALL_COMMENTS[A]{B=ALL_COMMENTS[A]}}}return B}function addCommentHierarchy(D,C){if(D){C[C.length]=D;var A=D.children;for(var B in A){addCommentHierarchy(findComment(A[B]),C)}}}function getCommmentsInSortedOrder(){var D=new Array();var A=getRootComments();for(var B in A){var C=A[B];addCommentHierarchy(C,D)}return D}function ParsedResult(A,B){this.parentComment=A;this.body=B;this.toString=function(){return"[parentComment="+this.parentComment+", body="+this.body+", ]"}}function findParentCommentFromDescriptor(A){var B=findComment(A);if(B==null){B=findLastCommentByAuthorName(A)}if(B==null){B=findLastCommentByPartialAuthorName(A)}return B}function parseCommentBody(B,F){B=trimString(B);var A=B.indexOf("@");if(A==0){var H=B.indexOf("\n",0);var G=B.indexOf("<",0);var D=H;if(G>0&&(G<D||D<0)){D=G}if(D>2){var O=B.substring(1,D);O=trimString(O);var K=findParentCommentFromDescriptor(O);if(K==null){var J=O.indexOf(" ");if(J>0){var N=trimString(O.substring(0,J));K=findParentCommentFromDescriptor(N);if(K!=null){D=J+1}}}if(K!=null){var P=null;var Q=D;var C=B.indexOf("@",Q+1);if(C>Q){var M=trimString(B.substring(C));P=parseCommentBody(M,C)}if(P&&P.length>0&&P[0].parentComment!=null){var L=trimString(B.substring(D,C));var I=new ParsedResult(K,L);var E=[I].concat(P);return E}else{var L=trimString(B.substring(D));var I=new ParsedResult(K,L);return[I]}return E}}}var I=new ParsedResult(null,B);return[I]}function buildComment(C,K,H,L,G,I,M,A){var F=findAuthor(C,K);if(!F){F=createAuthor(getNewAuthorId(),C,K);addAuthor(F)}var D=parseCommentBody(A,0);for(var J in D){var E="";E=D[J].body;E=trimBrsFromString(E);var B=createComment(H+"."+J,getNewCommentSequence(),L,F,I,M,E,G);addComment(B);if(D[J].parentComment!=null){D[J].parentComment.addChild(B)}}}function substituteConstant(A,D,C){var B=A;while(B.indexOf(D)>=0){B=B.replace(D,C)}return B}function substituteConstantIfValueExists(D,A,I,C,H){var J=D;var F=J.indexOf(A);var E=J.indexOf(I);while(F>0&&E>F){var B=J.substring(F,E+I.length);var G=null;if(H&&H.length>0){G=substituteConstant(B,C,H);G=G.substring(A.length,G.length-I.length)}else{G=""}J=J.replace(B,G);F=J.indexOf(A);E=J.indexOf(I)}return J}function isBlogAuthor(B){var A=false;if(window.BLOG_AUTHORS){for(var C in BLOG_AUTHORS){if(BLOG_AUTHORS[C]==B){A=true;break}}}else{if(window.BLOG_AUTHOR){A=(BLOG_AUTHOR==B)}}return A}function applyCommentTemplateToComment(F,E){var A=F;A=substituteConstant(A,"${COMMENT.ID}",;A=substituteConstant(A,"${COMMENT.TIMESTAMP}",E.postedTime);A=substituteConstant(A,"${COMMENT.AUTHOR.NAME}",;var C=(E.level>3)?"gt3":E.level;A=substituteConstant(A,"${COMMENT.LEVEL}",C);A=substituteConstantIfValueExists(A,"${COMMENT.AUTHOR.URL.EXISTS.START}","${COMMENT.AUTHOR.URL.EXISTS.END}","${COMMENT.AUTHOR.URL}",;A=substituteConstant(A,"${COMMENT.AUTHOR.URL}",;A=substituteConstant(A,"${COMMENT.DELETE.URL}",E.deleteUrl);A=substituteConstant(A,"${COMMENT.DELETE.TEXT}",E.deleteText);A=substituteConstant(A,"${COMMENT.BODY}",E.body);var D=isBlogAuthor("blog-author-comment":"blog-nonauthor-comment";A=substituteConstant(A,"${BLOG.AUTHOR}",D);A=substituteConstant(A,"${BLOG.POST.COMMENT.LINK}",BLOG_POST_COMMENT_LINK);var B=(E.deleted)?"deleted-comment":"";A=substituteConstant(A,"${COMMENT.DELETED.STYLE}",B);document.writeln(A)}function applyCommentTemplate(C){var D=getCommmentsInSortedOrder();for(var A in D){var B=D[A];applyCommentTemplateToComment(C,B)}}function setElementDisplay(B,C){var A=document.getElementById(B);if(A){}}function setElementsDisplay(B,C){for(var A in B){setElementDisplay(B[A],C)}}function showElements(A){setElementsDisplay(A,"block")}function hideElements(A){setElementsDisplay(A,"none")}function showElement(A){setElementDisplay(A,"block")}function hideElement(A){setElementDisplay(A,"none")}function toggleElementDisplays(C,B,D){if(C.innerHTML=="[hide]"){for(var A in B){if(D[A]=="both"||D[A]=="hide"){hideElement(B[A])}}C.innerHTML="[show]"}else{for(var A in B){if(D[A]=="both"||D[A]=="show"){showElement(B[A])}}C.innerHTML="[hide]"}};// ]]>

  2. Next you need add the css tyles for the comments section inside you <b:skin> section. Below is the one I am using in my blog:

    .comment-segment {
    margin-top: 10px;
    margin-right: 10px;
    .comment-level-0 {
    margin-left: 10px;
    .comment-level-1 {
    margin-left: 25px;
    .comment-level-2 {
    margin-left: 40px;
    .comment-level-3 {
    margin-left: 55px;
    .comment-level-gt3 {
    margin-left: 70px;
    .blog-author-comment {
    background-color: #F0F0BE;
    border: 1px solid #FFFF99;
    .blog-nonauthor-comment {
    background-color: #B4C8F0;
    border: 1px solid #7296E2;
    .deleted-comment {
    color: gray; font-STYLE: italic
    .delete-comment-icon {
    background: url("")
    .comment-time {
    font-size: 80%;
    margin: inherit;
    padding-left: 10px;
    padding-bottom: 10px;
    .reply-guide {
    background-color: #FFFFFF;
    border: #076a93 1px dotted;
    display: none;
    padding-right: 10px;
    padding-left: 10px;
    padding-bottom: 0.75em;
    padding-top: 5px;
    margin-right: 10px;
    margin-bottom: 10px;
    .reply-guide-header {
    color: #076a93;
    padding-top: 10px;
    .reply-guide-list {
    list-style: none;
    padding-left: 2px;
    margin-left: 2px;
    .reply-guide-example {
    font-size: 85%;
    margin-right: 5px;
    margin-bottom: 10px;
    float: right;
    border: 1px dotted #076a93;
    padding: 5 5 5 5;

  3. Lastly you need to insert the template for to render the threaded blog comments.
    You need to find the portion in your template responsible for rendering comment. In my template it started with:

    <b:includable id='comments' var='post'>
    <div class='comments' id='comments'>

    I just replaced that <b:includable> with the following:

    <b:includable id='comments' var='post'>
    <div class='comments' id='comments'>
    <a name='comments'/>
    <b:if cond='data:post.allowComments'>
    <b:if cond='data:post.numComments == 1'> 1 <data:commentLabel/>:

    <b:if cond='data:post.numComments > 0'>
    <!-- Include a post comment link before rendering the comments -->
    <p class='comment-footer'>
    <b:if cond='data:post.embedCommentForm'>
    <b:include data='post' name='comment-form'/>
    <b:if cond='data:post.allowComments'>
    <a expr:href='data:post.addCommentUrl'

    <!-- Loop through the comments adding the comment bodies in a hidden div -->
    <b:loop values='data:post.comments' var='comment'>
    <div style="display: none;" expr:id='"comment-body-" +' >
    <!-- Now create the comment using our javascript -->
    <script type="text/javascript">
    // USE THIS if YOU Have multiple Authors adding them in a comma separated form after removing the '//' from the next line
    // var BLOG_AUTHORS = ['', '', ''];
    // Use this if you have just one author like this blog :)
    var BLOG_AUTHOR = '';
    var BLOG_POST_COMMENT_LINK = '<data:post.addCommentUrl/>';

    var eCommentDelete = false;
    var eAuthorUrl = '';
    <b:loop values='data:post.comments' var='comment'>
    eCommentDelete = false;
    eAuthorUrl = '';
    <b:if cond='data:comment.authorUrl'>
    eAuthorUrl = "<data:comment.authorUrl/>";
    <b:if cond='data:comment.isDeleted'>
    eCommentDelete = true;

    buildComment("<>", eAuthorUrl,
    "<>", "<data:comment.timestamp/>", eCommentDelete,
    "<data:comment.deleteUrl/>", "<data:top.deleteCommentMsg/>",
    // <![CDATA[
    var eCommentTemplate = '' +
    '<div class="comment-segment comment-level-${COMMENT.LEVEL} ${BLOG.AUTHOR} ${COMMENT.DELETED.STYLE}" >' + '\n' +
    ' <a name="comment-${COMMENT.ID}"></a>' + '\n' +
    ' <span style="float: right; margin-right: 5px; " >' + '\n' +
    ' <a href="#" ' + '\n' +
    ' onclick="toggleElementDisplays(this, ' +
    '[\'comment-${COMMENT.ID}-body\', \'comment-${COMMENT.ID}-footer\', \'reply-guide-${COMMENT.ID}\'], ' +
    '[\'both\', \'both\', \'hide\']); return false;" >[hide]</a>' + '\n' +
    ' </span>' + '\n' +
    ' <span class="comment-author" >' +
    '<a href="${COMMENT.AUTHOR.URL}" rel="nofollow">' +
    '</a>' +
    '${COMMENT.AUTHOR.URL.EXISTS.END}</span>' + '\n' +
    ' said... ' + '\n' +
    ' <div id="comment-${COMMENT.ID}-body" class="comment-body" ><p>${COMMENT.BODY}</p></div>' + '\n' +
    ' <span class="comment-time">on ${COMMENT.TIMESTAMP}</span>' + '\n' +
    ' <div id="reply-guide-${COMMENT.ID}" class="reply-guide comment-level-0 " >' + '\n' +
    ' <span style="float: right;" ><a href="#" onclick="hideElement(\'reply-guide-${COMMENT.ID}\'); return false;" >[hide]</a></span>' + '\n' +
    ' <h4 class="reply-guide-header">How to Reply to this comment</h4>' + '\n' +
    ' <span>' + '\n' +
    ' To reply to this comment please ensure that <b>one</b> of the following lines: ' + '\n' +
    ' <ul class="reply-guide-list">' + '\n' +
    '<li>@${COMMENT.ID}</li>' + '\n' +
    '<li>@${COMMENT.AUTHOR.NAME}</li>' + '\n' +
    ' </ul>' + '\n' +
    ' is the <b>first line</b> of your comment. ' + '\n' +
    ' <br />' + '\n' +
    ' <a href="${BLOG.POST.COMMENT.LINK}"' + '\n' +
    ' >Click here to enter your reply</a>' + '\n' +
    ' </span>' + '\n' +
    ' </div>' + '\n' +
    ' <div id="comment-${COMMENT.ID}-footer" class="comment-footer">' + '\n' +
    ' <span><a ' +
    'href="#" onclick="showElement(\'reply-guide-${COMMENT.ID}\'); return false;" >Reply</a></span> ' + '\n' +
    ' <span><a href="#comment-${COMMENT.ID}">Permalink</a></span> ' + '\n' +
    ' <span><a href="${COMMENT.DELETE.URL}" title="${COMMENT.DELETE.TEXT}" style="text-decoration: none;" ><span class="delete-comment-icon"> </span></a></span>' + '\n' +
    ' </div>' + '\n' +
    '</div>' + '\n';

    // ]]>
    <p class='comment-footer'>
    <a expr:href='data:post.addCommentUrl' expr:onclick='data:post.addCommentOnclick'><data:postCommentMsg/></a>
    <div id='backlinks-container'>
    <div expr:id='data:widget.instanceId + "_backlinks-container"'>
    <b:if cond='data:post.showBacklinks'>
    <b:include data='post' name='backlinks'/>

Remember to replace the
var BLOG_AUTHOR = '';
segment with your appropriate profile url(s).

A sample blogger template is also available in case you want to skip some of the work.

Future work:
Unfortunately the way blogger comments need to be posted it is the responsibilty of the user now to include a @replyTarget line to the top of her comment. Once blogger supports inline comment forms completely (currently it is available only in draft mode) it will be possible to relieve the user of this task and use javascript to auto insert the @replyTarget line into the form.

Feel free to use this in your blogs and let me know your thoughts/bugs you find while using this :)


Sunday, May 4, 2008

Implementation of My Java7 Wishlist

Last month I blogged about my java7 wishlist regarding collections. There I was redirected to a similar post by Stephen Colebourne and also introduced to an open source project kijaro where others had implemented their wishlists and I could try out mine.

After three weekends I am now pleased to announce that I have implemented my wishlist. My implementation at a branch of kijaro contains a merger of my wishlist and those mentioned by Stephen in his blog. Features implemented are:

  • Array Index access syntax for Lists and Maps
    myList[0] instead of myList.get(0) and
    myMap[“key”] instead of myMap.get(“key”)

  • Concise syntax to initialize and fill Collections
    new HashMap<Integer, String>(5) [1: “one”, 2:”two”, 3:”three”, ]
    instead of
    HashMap<Integer, String> m1 = new HashMap<Integer, String>(5);
    m1.put(1, “one”);
    m1.put(2, “two”);
    m1.put(3, “three”);

There was a catch while implementing the second feature as the expression needed to be converted to another expression and not a series of statements. Hence I needed to make use of a utility method to execute the set of statements to populate a Collection or a Map.

It was really exciting for me to see a .java file with the above syntax compiled into a .class file. Below is an example of such a file and the corresponding jdk4 compliant code it was converted to during the compilation process.

public class TestConcise {
public static void main(String[] args) {
boolean b = new java.util.LinkedList<String>()
["a", "b", "c" ].add("d");
param(new java.util.ArrayList<String>() {
public boolean add(String e) {
return super.add(e);
} ["a", "b", "c" ]
java.util.Map<Integer, String> m1 = ret();
m1[2] = "two";

java.util.LinkedList<String> l1 = new
java.util.LinkedList<String>()["a", "b", "c" ];
m1[3] = l1[2];
l1[0] = m1[0];
l1[1] = "one";


private static void param(
final java.util.Collection<? extends Object> coll){

private static java.util.Map<Integer, String> ret() {
return new java.util.HashMap<Integer, String>() {}
[1:"a", 2:"b", ];

was converted to

class TestConcise$1 extends java.util.ArrayList {
TestConcise$1() {

public boolean add(String e) {
return super.add(e);

/*synthetic*/ public boolean add(Object x0) {
return this.add((String)x0);

class TestConcise$2 extends java.util.HashMap {
TestConcise$2() {

public class TestConcise {
public TestConcise() {

public static void main(String[] args) {
boolean b = java.util.CollectionUtil.fillCollection(
new java.util.LinkedList(),
new String[]{"a", "b", "c"}).add("d");
new TestConcise$1(), new String[]{"a", "b", "c"}));
java.util.Map m1 = ret();
m1.put(Integer.valueOf(2), "two");

java.util.LinkedList l1 =
new java.util.LinkedList(),
new String[]{"a", "b", "c"});
m1.put(Integer.valueOf(3), l1.get(2));
l1.set(0, m1.get(Integer.valueOf(0)));
l1.set(1, "one");


private static void param(
final java.util.Collection coll) {

private static java.util.Map ret() {
return java.util.CollectionUtil.fillMap(
new TestConcise$2(),
new Integer[]{Integer.valueOf(1), Integer.valueOf(2)},
new String[]{"a", "b"});


Saturday, April 5, 2008

My Java7 Wishlist regarding Collections

Update: I've implemented the features mentioned below. Read more about it at another post: Implementation of My Java7 Wishlist

There are tons of feature requests for java7. Most of the them center around closures, super-packages, extension methods, tuples, etc which are all new concepts for the language. I have been wondering why no one has bothered with improving support for some of the existing concepts/classes – in particular the syntax regarding Collection classes.

Collections have been a hot topic, although indirectly, with the introduction of generics in java 5. These classes are used more and more often in daily development – at least by me J and all my colleagues. So I am considering proposing giving the Collections citizens of java additional privileges like Arrays have receive right from the start. My wish list features mainly around syntactic enhancements to improve readability and make the code more concise (inspired by Rob’s CICE).

My first proposal revolves around making the collection instantiation syntax.
For a Collection class we might consider something similar to arrays:

Instead of:

Collection<String> c = new ArrayList();


Collection<String> c = new ArrayList {“one”, “two”, “three” };

For a Map instance we might consider the javascript like syntax:

Instead of:

Map<String, Integer> m = new HashMap();
m.put(“one”, 1);
m.put(“two”, 2);
m.put(“three”, 3);


Map<String, Integer> m = new HashMap { “one”:1, “two”:2, “three”:3 };

However it becomes tricky when we wish to invoke a particular conctructor of the actual implementing class. I am yet to come up with a pretty format for that one but something like

Collection<String> c = new ( ArrayList(3) ) { “one”, “two”, “three” };
Map<String, Integer> m = new ( HashMap(5, 0.8) ) { “one”:1, “two”:2, “three”:3 };

should work fine.

My second proposal is to allow syntax to treat Maps like Arrays. After all Maps are Associative Arrays J.
So one should be able to write

m[“four”] = 4;
int i = m[“two”] ;

instead of

m.put(“four”, 4);
int i = m.get(“two”);

These help make the code compact and more readable.

I would be glad if you shared with me what you think of this proposal or if you have any similar ideas.

Update: I've implemented the features mentioned above. Read more about it at another post: Implementation of My Java7 Wishlist


Thursday, March 6, 2008

Internationalize Swing's JFileChooser in Unicode (Bangla)

Recently I had to develop a small demo application for one of the leading newspapers in Bangladesh. I decided to localize my application and see all messages in Bangla. Searching Google I came across this article “Internationalization for Swing standard components”. This set me off in the right direction. However, there were some little tweaks I had to perform to get Bangla working. Firstly I had to set the font for the components user in JFileChooser.

final Font FONT_SOLAIMAN_LIPI = new Font("SolaimanLipi", Font.PLAIN, 15);
final FontUIResource eFontUIResource = new FontUIResource(FONT_SOLAIMAN_LIPI);
UIManager.put("Button.font", eFontUIResource);
UIManager.put("ToolTip.font", eFontUIResource);
UIManager.put("Label.font", eFontUIResource);
UIManager.put("EditorPane.font", eFontUIResource);
UIManager.put("TableHeader.font", eFontUIResource);

Next I had to set message values for properties as mentioned in Adrian's blog. However I had to set a couple of extra properties also


Finally there was this trouble of changing the tooltip for the home directory. The default JFileChooser implementation sets the tooltip to the name of the home directory which in my case (as will be in most cases :) ) was in english. So I had to end up writing a small visitor that would find the home folder button and reset the tooltip of the button as follows:

final String eHomeFolderName = eFileChooser.getFileSystemView().getHomeDirectory().getName();
MySwingComponentVisitor eVisitor = new MySwingComponentVisitor(eFileChooser, JButton.class) {
public boolean onComponentVisited(JComponent pVisitedComponent) {
JButton eButtonComponent = (JButton) pVisitedComponent;
if (eHomeFolderName.equals(eButtonComponent.getToolTipText())) {

And the results were just so pleasing. A JFileChooser almost entirely in Bangla. Below are images showing how the JFileChooser transformed :)

Click to enlarge
Click to enlarge


Wednesday, February 27, 2008

Shell script to find last created file in a directory

I'm quite new to shell scripting and with my introduction to pipes and the beginners ls and tail commands I was able to come up with quite a simple shell script to find the last modified file in a directory.

The idea is very simple, its built on top of three facts :
1) ls -t -r command which sorts the file in a directory by creation date in reverse order,
2) tail -n 1 command which outputs the last line of the input passed to it, and
3) '' , the pipe which redirects the output of one process to the input of another.

So finally I came up with this simple script :)

ls -t -r | tail -n 1