indiWiz.com

Apache Buildr is now a top-level Apache project. Buildr is a Java build tool which uses Ruby (and JRuby) and provides dependency management functionalities. Think Maven has got some real competition now!

To serve static content packaged as part of the portlet WAR, we generally take this approach:

<%=response.encodeURL(request.getContextPath()+"/js/project.js")%>

For generating dynamic content what do we do? In JSR 168 this was not possible. Thankfully, JSR 286 introduced this important concept. For creating dynamic content, just override the void serveResource(ResourceRequest request, ResourceResponse response) method in javax.portlet.ResourceServingPortlet (implemented by javax.portlet.GenericPortlet). A simple example:

    @Override
    public void serveResource(ResourceRequest request, ResourceResponse response)
            throws PortletException, IOException {
        String paramValue = request.getParameter("abc");
        System.out.println(paramValue);
        response.setCharacterEncoding("UTF-8");
        response.setContentType("text/plain");
        PrintWriter pw = response.getWriter();
        pw.println(paramValue);
        pw.close();
    }

To link to this dynamic content:

<portlet:resourceURL var="url">
  <portlet:param name="abc" value="Hello World"/>
</portlet:resourceURL>

<a href="<%=url%>">Dynamic link</a>

Sprockets (site) is described thus: Sprockets is a Ruby library that preprocesses and concatenates JavaScript source files. This is not a new idea, I have seen similar compiler in Liferay source for aggregating CSS files. Since this is sponsored by 37 Signals (creators or Ruby on Rails), Sprockets’s syntax can become a kind of standard. Already Prototype and Script.aculo.us JavaScript libraries (two OpenSource JavaScript libraries popular in RoR) comply to Sprockets’s syntax.

Apache Http Components project hosts an excellent library for making HTTP client requests. This is a simple example for making multipart/form-data request.

Dependencies to be added to you Maven project:

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpmime</artifactId>
    <version>4.0-beta2</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.0-beta2</version>
</dependency>

And finally the code to execute the request:

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.nio.charset.Charset;
import org.apache.http.HttpResponse;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.DefaultHttpClient;

...

// The input:
File f = ...;
String title = ...;
String desc = ...;

// The execution:
DefaultHttpClient httpclient = new DefaultHttpClient();

HttpPost method = new HttpPost("http://host:port/path");
MultipartEntity entity = new MultipartEntity();
entity.addPart("title", new StringBody(title, Charset.forName("UTF-8")));
entity.addPart("desc", new StringBody(desc, Charset.forName("UTF-8")));
FileBody fileBody = new FileBody(f);
entity.addPart("file", fileBody);
method.setEntity(entity);

HttpResponse response = httpclient.execute(method);
System.out.println(response.getStatusLine());

The history of Java WebDav client is discussed well in this blog: http://pragmaticchris.blogspot.com/2007/11/java-webdav-clients.html. There is one update to it though: the JackRabbit project has a well-defined WebDav client (extending Commons HTTP Client) available.

To add JackRabbit WebDav client to your Maven project, use this:

<dependency>
    <groupId>org.apache.jackrabbit</groupId>
    <artifactId>jackrabbit-webdav</artifactId>
    <version>1.6.0</version>
</dependency>

I will show one example of using the WebDav client which I had developed to upload content to an WebDav server:

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URL;
import org.apache.commons.httpclient.Credentials;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.UsernamePasswordCredentials;
import org.apache.commons.httpclient.auth.AuthScope;
import org.apache.commons.httpclient.methods.InputStreamRequestEntity;
import org.apache.commons.httpclient.methods.RequestEntity;
import org.apache.jackrabbit.webdav.client.methods.PutMethod;

...

// WebDAV URL:
final String baseUrl = ...;
// Source file to upload:
File f = ...;
try{
    HttpClient client = new HttpClient();
    Credentials creds = new UsernamePasswordCredentials("username", "password");
    client.getState().setCredentials(AuthScope.ANY, creds);

    PutMethod method = new PutMethod(baseUrl + "/" + f.getName());
    RequestEntity requestEntity = new InputStreamRequestEntity(
	    new FileInputStream(f));
    method.setRequestEntity(requestEntity);
    client.executeMethod(method);
    System.out.println(method.getStatusCode() + " " + method.getStatusText());
}
catch(HttpException ex){
    // Handle Exception
}
catch(IOException ex){
    // Handle Exception
}

To convert an XML based on a XSL, use this command:

$ xsltproc /path/to/xsl.xsl /path/to/xml.xml

The converted document will be written to STDOUT. To write to a particular file, you may use the -o parameter:

$ xsltproc /path/to/xsl.xsl /path/to/xml.xml -o out.html

Check the info/man pages for additional information.