DocumentElements.java

/**
 * Copyright (C) 2012-2014 Gist Labs, LLC. (http://gistlabs.com)
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
package com.gistlabs.mechanize.document.documentElements;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import com.gistlabs.mechanize.Resource;
//import com.gistlabs.mechanize.html.query.HtmlQueryStrategy;
import com.gistlabs.mechanize.document.node.Node;
import com.gistlabs.mechanize.util.Assert;

/**
 * Abstract implementation stub for page elements implementing dynamic caching of representations of DOM elements. 
 *  
 * @author Martin Kersten<Martin.Kersten.mk@gmail.com>
 */
public abstract class DocumentElements<T> implements Iterable<T> {
	protected final Resource page;
	protected final List<? extends Node> nodes;
		
	private final Map<Node, T> representations = new HashMap<Node, T>();
	
	public DocumentElements(Resource page, List<? extends Node> nodes) {
		Assert.notNull(nodes, "Nodes may not be null");
		
		this.page = page;
		this.nodes = nodes;
	}
	
	public Resource getPage() {
		return page;
	}
	
	protected T getCachedOrNewRepresentation(Node node) {
		if(node != null) {
			if(!representations.containsKey(node))
				representations.put(node, newRepresentation(node));
			
			return representations.get(node);
		}
		else
			return null;
	}

	protected abstract T newRepresentation(Node element);
	
	public T find(String csss) {
		for(Node node : nodes) {
			Node find = node.find(csss);
			if(find!=null)
				return getCachedOrNewRepresentation(node);
		}

		return null;		
	}
	
	/** Returns a list with all representations of all elements. */
	public List<T> getAll() {
		List<T> result = new ArrayList<T>();
		if (nodes != null)
			for(Node element : nodes) 
				result.add(getCachedOrNewRepresentation(element));
		return result;
	}
	
	public int size() {
		return nodes.size();
	}
	
	public T get(int index) {
		return getCachedOrNewRepresentation(nodes.get(index));
	}
		
	public Iterator<T> iterator() {
		return getAll().iterator();
	}
}