NewsFeed.java

//Copyright [2011] [Barry Books]

//   Licensed under the Apache License, Version 2.0 (the "License");
//   you may not use this file except in compliance with the License.
//   You may obtain a copy of the License at

//       http://www.apache.org/licenses/LICENSE-2.0

//   Unless required by applicable law or agreed to in writing, software
//   distributed under the License is distributed on an "AS IS" BASIS,
//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//   See the License for the specific language governing permissions and
//   limitations under the License.

package com.trsvax.tapestry.facebook.components;

import java.io.StringWriter;

import org.apache.tapestry5.ComponentResources;
import org.apache.tapestry5.MarkupWriter;
import org.apache.tapestry5.annotations.AfterRender;
import org.apache.tapestry5.annotations.BeginRender;
import org.apache.tapestry5.annotations.Environmental;
import org.apache.tapestry5.annotations.Parameter;
import org.apache.tapestry5.ioc.annotations.Inject;
import org.apache.tapestry5.services.javascript.JavaScriptSupport;

import com.trsvax.tapestry.facebook.services.FBAsyncSupport;

public class NewsFeed {

	@Parameter
	private String name;
	@Parameter
	private String link;
	@Parameter
	private String picture;
	@Parameter
	private String caption;
	@Parameter
	private String description;
	@Parameter
	private String message;

	@Environmental
	private FBAsyncSupport fbAsyncSupport;

	@Environmental
	private JavaScriptSupport javaScriptSupport;
	
	@Inject
	private ComponentResources resources;

	@BeginRender
	void beginRender(MarkupWriter writer) {
		String id = javaScriptSupport.allocateClientId(resources);
		writer.element("a","id",id,"href","#");
		javaScriptSupport.addScript("", "");
		fbAsyncSupport.init(init(id));
	}

	@AfterRender
	void afterRender(MarkupWriter writer) {
		writer.end();
	}

	String init(String id) {

		StringWriter init = new StringWriter();

		init.append(String.format(
				"Event.observe( document.getElementById('%s'), 'click',", id));
		init.append("function(event){");
		init.append("FB.ui(");
		init.append("{");
		init.append("method: 'feed',");
		if ( name != null ) {
		init.append(String.format("name: '%s',",name));
		}
		if ( link != null ) {
			init.append(String.format("link: '%s',",link));
		}
		if ( picture != null ) {
			init.append(String.format("picture: '%s',",picture));
		}
		if ( caption != null ) {
			init.append(String.format("caption: '%s',",caption));
		}
		if ( description != null ) {
			init.append(String.format("description: '%s',",description));
		}
		if ( message != null ) {
			init.append(String.format("message: '%s'",message));
		}
		init.append("},");
		init.append("function(response) {");

		init.append(" }");

		init.append(");");
		init.append("}");
		init.append(");\n");
		return init.toString();
	}
}