/*******************************************************************************
 * Copyright (c) 2005, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.wst.jsdt.internal.ui.text.java;

import org.eclipse.core.runtime.Assert;
import org.eclipse.wst.jsdt.core.CompletionProposal;
import org.eclipse.wst.jsdt.core.IJavaScriptElement;
import org.eclipse.wst.jsdt.core.IJavaScriptProject;
import org.eclipse.wst.jsdt.core.IMember;
import org.eclipse.wst.jsdt.core.JavaScriptModelException;

/**
 * Proposal info that computes the javadoc lazily when it is queried.
 *
 * 
 */
public abstract class MemberProposalInfo extends ProposalInfo {
	/* configuration */
	protected final IJavaScriptProject fJavaProject;
	protected final CompletionProposal fProposal;

	/* cache filled lazily */
	protected boolean fJavaElementResolved= false;

	/**
	 * Creates a new proposal info.
	 *
	 * @param project the java project to reference when resolving types
	 * @param proposal the proposal to generate information for
	 */
	public MemberProposalInfo(IJavaScriptProject project, CompletionProposal proposal) {
		Assert.isNotNull(project);
		Assert.isNotNull(proposal);
		fJavaProject= project;
		fProposal= proposal;
	}

	/**
	 * Returns the java element that this computer corresponds to, possibly <code>null</code>.
	 * 
	 * @return the java element that this computer corresponds to, possibly <code>null</code>
	 * @throws JavaScriptModelException
	 */
	public IJavaScriptElement getJavaElement() throws JavaScriptModelException {
		if (!fJavaElementResolved) {
			fJavaElementResolved= true;
			fElement= resolveMember();
		}
		return fElement;
	}

	/**
	 * Resolves the member described by the receiver and returns it if found.
	 * Returns <code>null</code> if no corresponding member can be found.
	 *
	 * @return the resolved member or <code>null</code> if none is found
	 * @throws JavaScriptModelException if accessing the java model fails
	 */
	protected abstract IMember resolveMember() throws JavaScriptModelException;


}