resourcecollection.java

A static analysis tool to find bugs in Java programs

/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 2004, University of Maryland
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs;

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

import edu.umd.cs.findbugs.ba.Location;

/**
 * A ResourceCollection defines all of the resources created
 * and used in a particular method.  It serves two related
 * purposes:
 * <ol>
 * <li> Define all of the resources which exist in the method, and
 * <li> Record where resources created in the method are created
 * </ol>
 * <p> This distinction is important because some resources
 * which exist in the method aren't created in the method:
 * for example, resources passed in as parameters.
 *
 * @author David Hovemeyer
 */
public class ResourceCollection <Resource> {
	private List<Resource> resourceList;
	private Map<Location, Resource> locationToResourceMap;

	/**
	 * Constructor.
	 * Creates empty collection.
	 */
	public ResourceCollection() {
		this.resourceList = new LinkedList<Resource>();
		this.locationToResourceMap = new HashMap<Location, Resource>();
	}

	/**
	 * Add a preexisting resource.
	 * That is, one that is not created within the analyzed method.
	 * Resources passed to the method as parameters fall into
	 * this category.
	 *
	 * @param resource the preexisting resource
	 */
	public void addPreexistingResource(Resource resource) {
		resourceList.add(resource);
	}

	/**
	 * Add a resource created within the analyzed method.
	 *
	 * @param location the location
	 * @param resource the resource created at that location
	 */
	public void addCreatedResource(Location location, Resource resource) {
		resourceList.add(resource);
		locationToResourceMap.put(location, resource);
	}

	/**
	 * Return whether or not there are any resources in the collection.
	 */
	public boolean isEmpty() {
		return resourceList.isEmpty();
	}

	/**
	 * Get an Iterator over all resources in the method.
	 * This includes both preexisting and created resources.
	 */
	public Iterator<Resource> resourceIterator() {
		return resourceList.iterator();
	}

	/**
	 * Get the resource that is created at given location.
	 *
	 * @param location the Location
	 * @return the Resource created at that location,
	 *         or null if no resource is created at the location
	 */
	public Resource getCreatedResource(Location location) {
		return locationToResourceMap.get(location);
	}
}

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