Java Behind Obvious

Highcharts both OX and OY logarithmic axis

2013-03-23T23:32:00.001-07:00

Today’s tip is about Highcharts. Few months ago, we have talk about Highstock JavaScript library. Well, Highcharts is pretty much the same, since both are developed by Highsoft Solutions AS. There are both pure JavaScript libraries for creating interactive charts, each of them offering some cool options for creating awesome charts for your website.

Highcharts currently supports line, spline, area, areaspline, column, bar, pie, scatter, angular gauges, arearange, areasplinerange, columnrange and polar chart types.

Today’s challenge for Highcharts is to create a line chart with both OX and OY logarithmic axis. The result will be:

And the code:

That’s it! Hope you like it! For more details and full documentation about Highcharts and Highstock, please visit official website.

How to find a point coordinates between other two points

2013-03-23T00:32:00.000-07:00

Theory: Given a segment from point A to point B, our goal is to find a C point coordinates at a specified distance on that segment.

Let’s say that DT is the distance of the AB segment and D is the distance from point A to point C.

Using the distance formula, we can find the distance from point A to point B:

Now, we can easily find the C point coordinates like this:

That’s it. From Java perspective, the mechanism looks like this:

package calculatelinepoints;

public class CalculateLinePoints {

public static void main(String[] args) {

// point A coordinates

double a = 20.0;

double b = 10.0;

// point B coordinates

double c = 50.0;

double d = 40.0;

// calculate distance between the two points

double DT = Math.sqrt(Math.pow((c - a), 2) + Math.pow((d - b), 2));

double D = 20.0; // distance to point C

double x;

double y;

double T = D / DT;

// finding point C coordinate

x = (1 - T) * a + T * c;

y = (1 - T) * b + T * d;

System.out.println("Point C coordinates:\n x: " + x + "\n y: " + y);

}

Fixing nsIDOMLSProgressEvent.input error

2012-12-18T08:22:00.000-08:00

Fixing error "NS_ERROR_NOT_IMPLEMENTED: Component returned failure code: 0x80004001 (NS_ERROR_NOT_IMPLEMENTED) [nsIDOMLSProgressEvent.input]" for PrimeFaces p:fileUpload

I found this solution on internet and I think it deserve to be shared. Adding this JS code fixes the above upload error:

$.blueimp.fileupload.prototype._initProgressListener = function (options) {

var that = this,

xhr = options.xhr ? options.xhr() : $.ajaxSettings.xhr();

// Accesss to the native XHR object is required to add event listeners

// for the upload progress event:

if (xhr.upload) {

$(xhr.upload).bind('progress', function (e) {

var oe = e.originalEvent;

// Make sure the progress event properties get copied over:

e.lengthComputable = oe.lengthComputable;

e.loaded = oe.loaded;

e.total = oe.total;

that._onProgress(e, options);

});

options.xhr = function () {

return xhr;

};

}

Reading a cookie from JSF

2012-12-18T08:05:00.001-08:00

If you ever need to read a cookie from JSF, maybe this will help you:

Object my_cookie = FacesContext.getCurrentInstance().getExternalContext()

.getRequestCookieMap().get("my_project");

if (my_cookie != null) {

String name = (((Cookie) my_cookie).getName());

String value = (((Cookie) my_cookie).getValue());

}

Working with JavaScript cookies

2012-12-18T07:49:00.002-08:00

Just a few methods for handling cookies with JavaScript:


function setCookie(c_name,value,exdays) {
    var exdate=new Date();
    exdate.setDate(exdate.getDate() + exdays);
    var c_value=escape(value) + ((exdays==null) ? "" : ";

    expires="+exdate.toUTCString());
    document.cookie=c_name + "=" + c_value;
}

function deleteCookie(c_name) {
    document.cookie = encodeURIComponent(c_name) + "=deleted; expires=" +
    new Date(0).toUTCString();
}

function getCookie(c_name) {
    var i,x,y,ARRcookies=document.cookie.split(";");
    for (i=0;i    {
        x=ARRcookies[i].substr(0,ARRcookies[i].indexOf("="));
        y=ARRcookies[i].substr(ARRcookies[i].indexOf("=")+1);
        x=x.replace(/^\s+|\s+$/g,"");
        if (x==c_name)
        {
            return unescape(y);
        }
    }
    return "nocookie";
}

Introducing Highstock JavaScript library

2012-08-26T06:54:00.000-07:00

     If you ever need to create dynamic interactive charts for you’re projects and you don’t know exactly how to do it or what to use, then Highstock may be a good solution for you. Highstock is a charting library written in pure JavaScript that lets you create stock or general timeline charts with sophisticated navigation options, preset date ranges, date picker, scrolling and panning.

    Highstock needs only three JavaScript files to run: the highstock.js, exporting.js (if you want to export the chart as .PDF, .JPEG or .PNG file) and either jQuery, MooTools or Prototype framework. You don’t need to use PHP, ASP.NET or client side plugins like Flash or Java to make Highstock work.

    Highstock supports line, spline, area, areaspline, column, scatter, OHLC, candlestick and flags chart types. The best thing of Highstock is that you can combine any of these char types in one chart. To test it, I’ve use two CSV files with data statistics for two websites.

    The CSV files contain a date and a value per each row and it looks like this:

...

1-6-2012,10

2-6-2012,30

3-6-2012,50

4-6-2012,40

5-6-2012,67

6-6-2012,89

...

And the code is:

<!DOCTYPE HTML>

<html>

<head>

<title>Highstock Example</title>

var site01 =[];

var site02 = [];

$(function() {

jQuery.ajax({

url: 'site02.csv',

success: function(data) {

// Split the lines

var lines = data.split('\n');

$.each(lines, function(lineNo, line) {

var index = line.indexOf(",");

var dm = line.substr(0,index);

var valoare = line.substr(index+1);

valoare = $.trim(valoare);

var points = dm.split('-');

if (valoare=='null'){

site02.push([Date.UTC(points[2],(points[1]-1),points[0]),null]);

}else{

site02.push([Date.UTC(points[2],(points[1]-1),points[0]),parseFloat(valoare)]);

}

});

if(data.isOk == false)

alert("Error loading site02.csv !");

async: false

});

jQuery.ajax({

url: 'site01.csv',

success: function(data) {

// Split the lines

var lines = data.split('\n');

$.each(lines, function(lineNo, line) {

var index = line.indexOf(",");

var dm = line.substr(0,index);

var valoare = line.substr(index+1);

valoare = $.trim(valoare);

var points = dm.split('-');

if (valoare=='null'){

site01.push([Date.UTC(points[2],(points[1]-1),points[0]),null]);

}else{

site01.push([Date.UTC(points[2],(points[1]-1),points[0]),parseFloat(valoare)]);

}

});

if(data.isOk == false) {

alert("Error loading site01.csv !");

} else {

createChart();

}

async: false

});

// create the chart when all data is loaded

function createChart() {

chart = new Highcharts.StockChart({

chart: {

renderTo: 'container',

zoomType: 'x'

plotOptions: {

series: {

marker: {

enabled: true

}

credits: {

enabled: false

navigation: {

buttonOptions: {

align: 'right'

}

exporting: {

width: 1000

title: {

text: 'Highstock demo'

subtitle: {

text: 'Introducing Highstock JavaScript library'

rangeSelector: {

selected: 1

tooltip: {

valueSuffix: ' views/day'

yAxis: {

labels: {

formatter: function() {

return this.value +' views';

}

title: {

text: 'Values'

}

series: [{

name: 'www.site-01.com',

data: site01,

connectNulls: false,

pointStart: Date.UTC(1970, 0, 1),

pointInterval: 3600 * 1000

{

name: 'www.site-02.com',

data: site02,

connectNulls: false,

pointStart: Date.UTC(1970, 0, 1),

pointInterval: 3600 * 1000

}

]

});

}

});

</script>

</head>

<body>

</body>

</html>

At the end, the chart will look like this:

Mastering CSS3 box-shadow

2012-07-06T08:47:00.002-07:00

This post want’s to bring up one of the great features introduced in CSS3, the box-shadow property. Now you can stop using images for displaying box-shadows, with just a few CSS lines you can create awesome effects. In this post, we will learn to add shadow effects on all four sides of a container:

The CSS3 code:

div {

border:1px solid #EEE9E9;

padding:30px;

height:50px;

width:200px;

margin:50px;

float:left;

}

.bottom{

-webkit-box-shadow:0 12px 10px -8px #00688B;

-moz-box-shadow:0 12px 10px -8px #00688B;

box-shadow:0 12px 10px -8px #00688B;

}

.top{

-webkit-box-shadow:0 -10px 15px -10px #00688B;

-moz-box-shadow:0 -10px 15px -10px #00688B;

box-shadow:0 -10px 15px -10px #00688B;

}

.inset-top-bottom{

-webkit-box-shadow:inset 0 8px 15px -8px #00688B,inset 0 -8px 15px -8px #00688B;

-moz-box-shadow:inset 0 8px 15px -8px #00688B,inset 0 -8px 15px -8px #00688B;

box-shadow:inset 0 8px 15px -8px #00688B,inset 0 -8px 15px -8px #00688B;

}

.left-right{

-webkit-box-shadow:10px 0 12px -8px #00688B,-10px 0 12px -8px #00688B;

-moz-box-shadow:10px 0 12px -8px #00688B,-10px 0 12px -8px #00688B;

box-shadow:10px 0 12px -8px #00688B,-10px 0 12px -8px #00688B;

}

.left-right-bottom{

-webkit-box-shadow:10px 0 12px -8px #00688B,-10px 0 12px -8px #00688B,0 8px 12px -6px #00688B;

-moz-box-shadow:10px 0 12px -8px #00688B,-10px 0 12px -8px #00688B,0 8px 12px -6px #00688B;

box-shadow:10px 0 12px -8px #00688B,-10px 0 12px -8px #00688BB,0 8px 12px -6px #00688B;

}

The HTML code:

<body>

CSS3 bottom shadow

</div>

CSS3 top shadow

</div>

CSS3 inset top-bottom shadow

</div>

CSS3 left-right shadow

</div>

CSS3 left-right-bottom shadow

</div>

</body>

And the output will be:

Solving GlassFish 3.1/JSF PWC4011 warning

2012-07-04T02:56:00.001-07:00

When you combine GlassFish 3.1 and JSF, it sometimes cause in Glassfish server.log file the warning:

“PWC4011 Unable to set request character encoding to UTF-8 from context ...”

To get rid of this warning, you need to add in glassfish-web.xml a few lines:

<!DOCTYPE glassfish-web-app PUBLIC "-//GlassFish.org//DTD GlassFish Application Server 3.1 Servlet 3.0//EN" "http://glassfish.org/dtds/glassfish-web-app_3_0-1.dtd">

<glassfish-web-app error-url="">

<parameter-encoding default-charset="UTF-8"/>

</glassfish-web-app>

Resolving JSF1091 in PrimeFaces

2012-07-04T02:32:00.000-07:00

“JSF1091: No mime type could be found for file dynamiccontent. To resolve this, add a mime-type mapping to the applications web.xml”

This error comes in various PrimeFaces situations, in this case, when I’ve try to load an extern CSS file which has style and links to some images. But my images fail to load and this error appears. So I’ve try to add to my web.xml file the mine-mapping tag, but still no result.

Finally, the solution to this error was to load the CSS file like this:

<h:head>

<f:facet name="last">

href="#{facesContext.externalContext.requestContextPath}/resources/css/style.css" />

</f:facet>

...

</h:head>

Accesing files outside a JAR

2012-06-23T01:06:00.000-07:00

First, get out of current JAR in JAR’s parent folder:

private String outJarPath = new File(getClass().getProtectionDomain()

.getCodeSource().getLocation().getPath()).getParent();

Then, create the path to you’re file:

outJarPath = outJarPath.replace("%20", " ");

String filePath = outJarPath + File.separator + "files" + File.separator + "file01.txt";

// Do something with the file

Introducing the HTML5 progress element

2012-06-17T05:13:00.002-07:00

One of the great features of HTML5 is the <progress> element. The <progress> element represents the progress of a task, you can use it to display an upload progress per example. To create a dinamic progress bar, we need to combine HTML5 with some JavaScript:

<!DOCTYPE html>

<html>

<head>

function startProgress() {

var progressBar = document.getElementById("progressBar"),

loaded = 0;

function load() {

loaded += 5;

progressBar.value = loaded;

document.getElementById("progress").innerHTML = "Progress: " + loaded + " %";

if(loaded == 100) {

clearInterval(interval);

document.getElementById("progress").innerHTML = "Complete !";

}

};

var interval = setInterval(function(){load();}, 1000);

}

</script>

</head>

<body>

The progress element is currently supported in Firefox, Opera, and Chrome.

</progress>

<button type="button" onclick="startProgress()">Start progress</button>

</body>

</html>

And the output will be:

The < progress > tag is currently supported in Firefox, Opera and Chrome.

value="0" – specifies how much of the task has been completed

max="100" – specifies how much work the task requires in total

For more informations, please visit http://www.w3.org/TR/html5/the-progress-element.html#the-progress-element.

Introducing the HTML5 datalist element

2012-06-14T01:46:00.002-07:00

The HTML5 <datalist> element specifies a list of pre-defined options for an <input> element and it works like an “autocomplete” feature for users:

<!DOCTYPE html>

<html>

<body>

User:

</datalist>

Password:

</form>

</body>

</html>

And the output will be:

The <datalist> tag is currently supported in Firefox and Opera. We can just hope that other browsers will soon support this great feature.

For more informations, please visit http://www.w3.org/TR/html5/the-datalist-element.html#the-datalist-element.

Introducing the HTML5 canvas element

2012-06-12T05:54:00.000-07:00

The HTML5 <canvas> element is the container for graphics, the place where you can draw graphics using a script. Since JavaScript seems to be the most used scripting language, in this example, we used JavaScript to draw some text inside a gradient rectangle.

<!DOCTYPE html>

<html>

<body>

<canvas width="800" height="600" id="canvas">Your browser does not support the canvas tag.</canvas>

var canvas = document.getElementById('canvas');

var c = canvas.getContext('2d');

var gradient = c.createLinearGradient(0,0,200,200);

gradient.addColorStop(0, "#F0E68C");

gradient.addColorStop(1, "crimson");

c.fillStyle = gradient;

c.fillRect(0,0,550,300);

c.fillStyle = "#fff";

c.font = "italic 30pt Arial";

c.shadowColor = "#000";

c.shadowOffsetX = 0;

c.shadowOffsetY = 0;

c.shadowBlur = 20;

c.fillText("This is a canvas example !", 50,150);

</script>

</body>

</html>

And the output will be:

The <canvas> tag is supported in Internet Explorer 9 (earlier versions does not support the <canvas> element), Firefox, Opera, Chrome and Safari.

For more informations, please visit http://www.w3.org/TR/html5/the-canvas-element.html#the-canvas-element.

Introducing the HTML5 embed element

2012-06-12T03:41:00.001-07:00

In HTML5, the <embed> element defines a container for an external application or interactive content (a plug-in). In this example, we will use it to display a Flash movie:

<!DOCTYPE html>

<html>

<body>

</body>

</html>

And the output will be:

The <embed> tag is supported in Internet Explorer, Firefox, Opera, Chrome and Safari.

type="application/x-shockwave-flash" – specifies the MIME type of the embedded content

For more informations, please visit http://www.w3.org/TR/html5/the-embed-element.html#the-embed-element.

Introducing the HTML5 video element

2012-06-11T05:33:00.000-07:00

Forget using the <iframe> element for sharing videos to your friends. There is an easier way to do this. Now, with HTML5 you can use the <video> element:

<!DOCTYPE html>

<html>

<body>

Your browser does not support the video tag.

</video>

</body>

</html>

And the output will be:

The <video> tag is supported in Internet Explorer 9 (earlier versions does not support the <video> element), Firefox, Opera, Chrome and Safari.

poster="poster.jpg" – specifies an image to be shown while the video is downloading, or until the user hits the play button

For more informations, please visit http://www.w3.org/TR/html5/the-video-element.html#the-video-element .

Introducing the HTML5 audio element

2012-06-11T01:31:00.002-07:00

We all know that adding music to a website has always been a challenge. Till now, developers had to create or add to their websites an audio player but since HTML5 appears, things gone easier by using the <audio> element:

<!DOCTYPE html>

<html>

<body>

Your browser does not support the audio element.

</audio>

</body>

</html>

And the output will be:

The <audio> tag is supported in Internet Explorer 9 (earlier versions does not support the <audio> element), Firefox, Opera, Chrome and Safari.

autoplay="autoplay" – specifies if the audio will start playing as soon as it is ready

loop="loop" – specifies if the audio will start all over again every time it is finished

For more informations, please visit http://www.w3.org/TR/html5/the-audio-element.html#the-audio-element .

How to kill a Windows process from the command line with taskkill

2012-05-05T05:57:00.000-07:00

If we have a certain process running on a certain port type, on Windows machines we can force shutdown a process folowing a few steps:

1. First, run Command Prompt and write: netstat –a –o –n

2. Then, locate the process and port type you want to shutdown and remember his PID, which is a unique identifier of the process.

For this test, we choose to shutdown Tomcat 6.0 that runs on port 8080.

3.And the final step, write: taskkill /F /PID 2052

In this case, 2052 is the unique identifier of the process. We will see a short message like:

That’s it! Quite simple.

Accessing the tag content from JavaScript

2012-05-04T23:47:00.000-07:00

Hi again ! For a recent project, I had to use the power of Javascript to obtain the <span> tag content. The first thing that came to my mind was by using the Javascript innerText property, but this was a bad idea. It seems that IE, Crome and Opera supports the innerText property but Firefox doesn’t. Apparently the proper DOM property to use for Firefox is textContent. The textContent property does the same thing as innerText property, at least as a result.

All said, I’ve obtained this code:

function getInnerText(){

if (document.getElementById("x").innerText) {

alert("For IE, Crome and Opera: " + document.getElementById("x").innerText);

} else {

if (document.getElementById("x").textContent) {

alert("For Mozilla Firefox: " + document.getElementById("x").textContent);

} else {

alert("Error: This application does not support your browser."

+ " Try again using IE or Firefox.");

}

And the HTML is:

<span id="x" onclick="getInnerText();">Click me!</span>

Then, a second idea had come to my mind. An idea that works in all major browsers without using the if clause. This idea is based on the innerHTML property:

function getInnerText () {

alert("For all browsers: " + document.getElementById("x").innerHTML);

}

That’s all. Hope it helps!

How to upload with PrimeFaces 3.2 under Tomcat 6

2012-04-17T00:50:00.012-07:00

Download a complete example tested under Tomcat 6 from here

Few months ago I’ve wrote the “How to upload with PrimeFaces under Tomcat 6” tip which was using the PrimeFaces 2.2 version. Since then, PrimeFaces has been changed and the current version, 3.2, has a lot of new great features. In this tip, we will explore all these features.

For start, you will need the following JARs, under your /lib folder (you can take them separately from web, or if you take this complete example from http://www.filefactory.com/file/3lnbxg0x85d/n/primeFileUpload.rar, then they are already included):
- primefaces-3.2.jar (this is what I’ve used, but you can take the latest Prime Faces library from PrimeFaces site – http://www.primefaces.org).
- jsf-api-2.0.2-FCS.jar (again, take the latest, if you consider that you need it)
- jsf-impl-2.0.2-FCS.jar
- el-api-2.2.jar
- el-impl-2.2.jar
- commons-io-1.4.jar
- commons-fileupload-1.2.jar

Next, I’ve configure the application descriptor, web.xml (depending on Prime Faces version, these configurations may be slightly different). In this descriptor I’ve configured Prime Faces upload filter and the ui-lightness-1.0.4 PrimeFaces theme:


<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
 "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
<web-app>            
    <context-param>
        <description>Context param for JSTL 1.2 to work in Tomcat 6 sun RI
        </description>
        <param-name>com.sun.faces.expressionFactory</param-name>
        <param-value>com.sun.el.ExpressionFactoryImpl</param-value>
    </context-param>
    <context-param>
        <description>Parameter required by Mojarra 2.0</description>
        <param-name>com.sun.faces.allowTextChildren</param-name>
        <param-value>true</param-value>
    </context-param>
    <context-param>
        <param-name>javax.faces.VALIDATE_EMPTY_FIELDS</param-name>
        <param-value>true</param-value>
    </context-param>
    <!-- Adding a PrimeFaces theme --> 
    <context-param>
 <param-name>primefaces.THEME</param-name>
 <param-value>ui-lightness</param-value>
    </context-param>    
    <filter>
        <filter-name>PrimeFaces FileUpload Filter</filter-name>
        <filter-class>org.primefaces.webapp.filter.FileUploadFilter
        </filter-class>
        <init-param>
            <param-name>thresholdSize</param-name>
            <param-value>10240</param-value> <!-- 10 Mb -->
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>PrimeFaces FileUpload Filter</filter-name>
        <servlet-name>Faces Servlet</servlet-name>
    </filter-mapping>  
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>   
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>/faces/*</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>faces/index.xhtml</welcome-file>
    </welcome-file-list>   
</web-app>

Next, I wrote a simple JSF page to test the Prime Faces upload component:


<html xmlns="http://www.w3c.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:p="http://primefaces.org/ui">
    <h:head>
        <title>Prime Faces</title>
        <style type="text/css">
            .ui-fileupload {
                width: 800px;
                margin: 0 auto;
            }
        </style>
    </h:head>
    <h:body>
        <h:outputText value="PrimeFaces Single Upload" 
                              style="font:30px bold; margin-left:15%;"/>
        <h:form enctype="multipart/form-data">
        <p:fileUpload fileUploadListener="#{fileUploadController.handleFileUpload}"
                mode="advanced"
                update="messages"
                label="Choose a file"
                sizeLimit="1048576"
                allowTypes="/(\.|\/)(gif|jpe?g|png)$/"
                invalidSizeMessage="The maximum file size allowed is 1 Megabyte !"
                invalidFileMessage="You are allowed to upload only images !"
                />
            <p:growl id="messages" showDetail="true" sticky="true"/>
        </h:form>

        <h:outputText value="PrimeFaces Multiple Upload" 
                              style="font:30px bold; margin-left:15%;"/>
        <h:form enctype="multipart/form-data">
        <p:fileUpload fileUploadListener="#{fileUploadController.handleFileUpload}"
                mode="advanced"
                update="messages"
                label="Choose a file"
                sizeLimit="10485760"
                multiple="true"
                allowTypes="/(\.|\/)(gif|jpe?g|png)$/"
                invalidSizeMessage="The maximum file size allowed is 10 Megabytes !"
                invalidFileMessage="You are allowed to upload only images !"
                />
            <p:growl id="messages" showDetail="true" life="5000"/>
        </h:form>

        <h:outputText value="PrimeFaces Auto Upload" 
                              style="font:30px bold; margin-left:15%;"/>
        <h:form enctype="multipart/form-data">
        <p:fileUpload fileUploadListener="#{fileUploadController.handleFileUpload}"
                 mode="advanced"
                 update="messages"
                 label="Choose a file"
                 auto="true"
                 sizeLimit="10485760"
                 allowTypes="/(\.|\/)(gif|jpe?g|png)$/"
                 invalidSizeMessage="The maximum file size allowed is 10 Megabytes !"
                 invalidFileMessage="You are allowed to upload only images !"
                 />
            <p:growl id="messages" showDetail="true" life="5000"/>
        </h:form>

        <h:outputText value="PrimeFaces Drag and Drop Upload" 
                              style="font:30px bold; margin-left:15%;"/>
        <h:form enctype="multipart/form-data">
        <p:fileUpload fileUploadListener="#{fileUploadController.handleFileUpload}"
                 mode="advanced"
                 update="messages"
                 label="Choose a file or drag and drop it here"
                 sizeLimit="10485760"
                 allowTypes="/(\.|\/)(gif|jpe?g|png)$/"
                 invalidSizeMessage="The maximum file size allowed is 10 Megabytes !"
                 invalidFileMessage="You are allowed to upload only images !"
                 />
            <p:growl id="messages" showDetail="true" life="5000"/>
        </h:form>
    </h:body>
</html>

As you can see, p:fileUpload is very flexible and customizable, allowing us to specify upload characteristics with a few simple attributes. Going further, we need a managed bean capable of dealing with upload itself. A possible implementation (probably not the best, but for sure not the worst) is listed below:


package com.extensions;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import javax.faces.FacesException;
import javax.faces.application.FacesMessage;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.faces.event.ActionEvent;
import org.primefaces.event.FileUploadEvent;

@ManagedBean(name = "fileUploadController")
@RequestScoped
public class uploadFilesBean {
   
    //Primitives
    private static final int BUFFER_SIZE = 6124;    
    private String folderToUpload;
    
    /** Creates a new instance of UploadBean */
    public uploadFilesBean() {
    }
    
    public void handleFileUpload(FileUploadEvent event) {
       
            ExternalContext extContext = 
                          FacesContext.getCurrentInstance().getExternalContext();
            File result = new File(extContext.getRealPath
                         ("//WEB-INF//files//" + event.getFile().getFileName()));
            System.out.println(extContext.getRealPath
                         ("//WEB-INF//files//" + event.getFile().getFileName()));

            try {
                FileOutputStream fileOutputStream = new FileOutputStream(result);

                byte[] buffer = new byte[BUFFER_SIZE];

                int bulk;
                InputStream inputStream = event.getFile().getInputstream();
                while (true) {
                    bulk = inputStream.read(buffer);
                    if (bulk < 0) {
                        break;
                    }
                    fileOutputStream.write(buffer, 0, bulk);
                    fileOutputStream.flush();
                }

                fileOutputStream.close();
                inputStream.close();

                FacesMessage msg = 
                            new FacesMessage("File Description", "file name: " +
                            event.getFile().getFileName() + "<br/>file size: " + 
                            event.getFile().getSize() / 1024 + 
                            " Kb<br/>content type: " + 
                            event.getFile().getContentType() + 
                                    "<br/><br/>The file was uploaded.");
                FacesContext.getCurrentInstance().addMessage(null, msg);

            } catch (IOException e) {
                e.printStackTrace();

                FacesMessage error = new FacesMessage(FacesMessage.SEVERITY_ERROR,
                                               "The files were not uploaded!", "");
                FacesContext.getCurrentInstance().addMessage(null, error);
            }       
    }    
}

The uploaded files goes to /WEB-INF/files folder.

Here it is a nice screenshot of Prime Faces upload:

That’s it ! Hope you like it !

Download a complete example tested under Tomcat 6 from here

How to programmatically access PrimeFaces tags

2012-04-16T23:25:00.005-07:00

This is FYI kind tip. Recently, I tried to programmatically acess PrimeFaces tags from Java beans. I found two solutions that can be extrapolated to almost all PrimeFaces tags.

1. Use the findComponent() method

Per example, the below code contains a DataTable, and I want to programmatically to set the zero-relative row number of the first row to be displayed.


<p:layoutUnit position="center" styleClass="welcome">
 <p:tabView id="centerTabIds" activeIndex="2">
  <p:tab title="LBD">
   <p:accordionPanel id="dataId">
    <p:tab title="Data Table Viewer">
     <h:panelGrid columns="1" cellpadding="5" 
                                style="margin-left: auto; margin-right: auto;">
      <h:form id="tableViewFormId" prependId="false">
       <p:dataTable id="tableViewId" var="t" value="#{tableViewBean.lazyModel}" 
                paginator="true" rows="5" 
                currentPageReportTemplate="{currentPage} of {totalPages}" 
                paginatorTemplate="{RowsPerPageDropdown} {FirstPageLink} 
                {PreviousPageLink} {CurrentPageReport} {NextPageLink} {LastPageLink}"
                rowsPerPageTemplate="5,10" emptyMessage="No records found" 
                paginatorPosition="top" first="0"> 
        <f:facet name="header">  
          Data Table 
        </f:facet> 
        <c:forEach items="#{tableViewBean.simpleColumns}" var="column">                                                                                     
          <p:column headerText="#{column.header}">                                            
            <h:outputText value="#{t[column.property]}"/> 
          </p:column>                                              
        </c:forEach>
        <f:facet name="footer"> 
          <c:when test="#{not empty tableViewBean.selectedTable}">
            <h:outputText value="#{tableViewBean.selectedTable}" />
          </c:when>
        </f:facet>
      </p:dataTable>
     </h:form>
    </h:panelGrid>
   </p:tab>
  </p:accordionPanel>                            
 </p:tab>
...

And here it is the programmatically solution using the findComponent() method:


((DataTable)(FacesContext.getCurrentInstance().getViewRoot().findComponent(
"centerTabIds:dataId:tableViewFormId:tableViewId"))).setFirst(0);

This is a tip in a tip – using multiple dynamic data tables and switching between them will get you to an unpleasant situation. PrimeFaces does not reset the data table to the first page every time you switch to another table, but this code fixes that problem.

Even if it is not a good idea to hardcode components ids, this can save a lot of time when no solution is available.

2. Use ActionEvent

Another common scenario is like this: I have a PrimeFaces menu, with several menu items. Each menu item has a value attribute, and all of them indicates the same action listener. I want to get the value of the menu item that was selected. The code looks like this:


...
<c:forEach items="#{iccAnalysisBean.wellIds}" var="row">                                                                                     
  <p:menuitem value="#{row.toString()}" 
            actionListener="#{iccAnalysisBean.selectedWellAction}" ajax="true"/>
</c:forEach>
...

And I’ve accommplish my task like this:


public void selectedWellAction(ActionEvent e) {
  String valueOfWell = String.valueOf(e.getComponent().getAttributes().get("value"));
...
}

I hope that this will help you when you are stack in such issues!

How to create a fixed list in Java using Apache Commons FixedSizeList class

2012-02-25T04:29:00.005-08:00

There are many ways to create a fixed list in Java, one of them is by using the FixedSizeList class, found in the Apache org.apache.commons.collections package (http://commons.apache.org/collections/). FixedSizeList does not support the add, remove, clear and retain methods and the set method is allowed as far as it doesn’t change the list size:


package fixedsizelist.exemple;

import java.util.Arrays;
import java.util.List;
import org.apache.commons.collections.list.FixedSizeList;

public class FixedSizeListExemple {

    public static void main(String[] args) {

        List fixedList = FixedSizeList.decorate(Arrays.asList(new String[5]));

        fixedList.set(0, "some_name@yahoo.com");
        fixedList.set(1, "some_other_name@gmail.com");
        fixedList.set(2, "777_name@rocketmail.com");
        fixedList.set(3, "bond_007@yahoo.com");
        fixedList.set(4, "james99@yahoo.com");

        System.out.println("\tDisplay list values...\n");
        for (String obj : fixedList) {
            System.out.println(obj.toString());
        }

        try {
            System.out.println("\n\tTrying to modify our fixed list...\n");

            fixedList.add("paul01_mac@yahoo.com");
            fixedList.remove(3);
            fixedList.clear();

        } catch (Exception e) {
          System.out.println
          (" The add, remove, clear and retain operations are unsupported."
          + "\nThe set method is allowed (as it doesn't change the list size).\n");
        }
    }
}

And the output is:

How to allow duplicate key in Java Collections

2012-02-24T08:20:00.007-08:00

Java Collections allows you to add one or more elements with the same key by using the MultiValueMap class, found in the Apache org.apache.commons.collections package (http://commons.apache.org/collections/):


package multihashmap.example;

import java.util.Iterator;
import java.util.List;  
import java.util.Map;
import java.util.Set;
import org.apache.commons.collections.map.MultiValueMap;

public class MultiHashMapExample {

    public static void main(String[] args) {

        List list;
        MultiValueMap map = new MultiValueMap();
        map.put("A", 4);
        map.put("A", 6);
        map.put("B", 7);
        map.put("C", 1);
        map.put("B", 9);
        map.put("A", 5);

        Set entrySet = map.entrySet();
        Iterator it = entrySet.iterator();
        System.out.println("  Object key  Object value");
        while (it.hasNext()) {
            Map.Entry mapEntry = (Map.Entry) it.next();
            list = (List) map.get(mapEntry.getKey());
            for (int j = 0; j < list.size(); j++) {
                System.out.println("\t" + mapEntry.getKey() + "\t  " + list.get(j));
            }
        }
    }
}

Since Java Core does’t come with some solutions for supporting multiple keys, using the org.apache.commons.collections seems to be a proper way to deal with multiple keys.

And the output is:

Java Numerical Solutions — Java.net

2012-02-11T09:26:00.000-08:00

Java Numerical Solutions — Java.net

Cropping, rotate and resizing images

2012-02-10T01:35:00.000-08:00

This is FYI kind tip. Recently, I have looked for some cool Java libraries for cropping, rotating and resizing images. I was looking for something small, fast, flexible and very easy to use. And I found it at http://www.thebuzzmedia.com/software/imgscalr-java-image-scaling-library/. It main advantages are:

• 100% Java code based on Java2D, no native libraries to install
• Java that works in “headless” environments without special environment variable settings; it just works.
• Because there are no native libraries, you mitigate the risk of native libraries crashing the host VM (e.g. your app server) or thread-contention issues
• Hardware accelerated on supported platforms (uses the optimized Java2D rendering pipeline)
• Fast; not faster than a native-C solution, but still damn fast.
• Simple, simple, simple. A handful of static, 1-word methods you can call. No complex configurations, managers, encoders/decoders or any other nonsense. imgscalr is not a “graphics library”, it is a set of the most commonly used graphic operations, optimized and ready to do your bidding.

Well, per example a resize can be accomplished like this:


BufferedImage bimage = Scalr.resize(bimage, Method.QUALITY, Mode.FIT_EXACT, width,
                      height);

This is just one case, but as you can see in javadoc – http://www.thebuzzmedia.com/downloads/software/imgscalr/javadoc/index.html, this is exactly what you need for cropping, rotating and resizing images.

Sorting a HashMap By Values Without Losing Duplicates

2011-12-21T08:25:00.000-08:00

The below method sorts a HashMap by values without removing duplicates. It works for <String,String> but it can be modified accordingly for other types:


    private LinkedHashMap sortMapByValuesWithDuplicates(Map passedMap) {
        List mapKeys = new ArrayList(passedMap.keySet());
        List mapValues = new ArrayList(passedMap.values());
        Collections.sort(mapValues);
        Collections.sort(mapKeys);

        LinkedHashMap sortedMap = new LinkedHashMap();

        Iterator valueIt = mapValues.iterator();
        while (valueIt.hasNext()) {
            Object val = valueIt.next();
            Iterator keyIt = mapKeys.iterator();

            while (keyIt.hasNext()) {
                Object key = keyIt.next();
                String comp1 = passedMap.get(key).toString();
                String comp2 = val.toString();

                if (comp1.equals(comp2)) {
                    passedMap.remove(key);
                    mapKeys.remove(key);
                    sortedMap.put((String) key, (String) val);
                    break;
                }
            }
        }
        return sortedMap;
    }