/*******************************************************************************
* Copyright (c) 2002 - 2006 IBM Corporation.
* 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 com.ibm.wala.util.graph;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import com.ibm.wala.util.collections.HashSetFactory;
/**
* TODO: Move this somewhere.
*/
public class InferGraphRoots {
public static <T> Collection<T> inferRoots(Graph<T> g){
if (g == null) {
throw new IllegalArgumentException("g is null");
}
HashSet<T> s = HashSetFactory.make();
for (Iterator<? extends T> it = g.iterator(); it.hasNext();) {
T node = it.next();
if (g.getPredNodeCount(node) == 0) {
s.add(node);
}
}
return s;
}
}