WALA/com.ibm.wala.util/src/com/ibm/wala/util/graph/traverse/NumberedDFSDiscoverTimeIter...

107 lines
3.3 KiB
Java

/*******************************************************************************
* 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.traverse;
import java.util.Iterator;
import com.ibm.wala.util.collections.NonNullSingletonIterator;
import com.ibm.wala.util.graph.NumberedGraph;
/**
* This class implements depth-first search over a NumberedGraph, return an enumeration of the nodes of the graph in order of
* increasing discover time. This class follows the outNodes of the graph nodes to define the graph, but this behavior can be
* changed by overriding the getConnected method.
*/
public class NumberedDFSDiscoverTimeIterator<T> extends GraphDFSDiscoverTimeIterator<T> {
private static final long serialVersionUID = -3919708273323217304L;
/**
* An iterator of child nodes for each node being searched
*/
private final Iterator<? extends T>[] pendingChildren;
/**
* The Graph being traversed
*/
protected final NumberedGraph<T> G;
/**
* Construct a depth-first enumerator starting with a particular node in a directed graph.
*
* @param G the graph whose nodes to enumerate
* @throws IllegalArgumentException if G is null
*/
@SuppressWarnings("unchecked")
public NumberedDFSDiscoverTimeIterator(NumberedGraph<T> G, T N) {
if (G == null) {
throw new IllegalArgumentException("G is null");
}
this.G = G;
pendingChildren = new Iterator[G.getMaxNumber() + 1];
init(G, new NonNullSingletonIterator<>(N));
}
/**
* Construct a depth-first enumerator across the (possibly improper) subset of nodes reachable from the nodes in the given
* enumeration.
*
* @param G the graph whose nodes to enumerate
* @param nodes the set of nodes from which to start searching
* @throws IllegalArgumentException if G is null
* @throws IllegalArgumentException if nodes == null
*/
@SuppressWarnings("unchecked")
public NumberedDFSDiscoverTimeIterator(NumberedGraph<T> G, Iterator<? extends T> nodes) throws IllegalArgumentException {
if (G == null) {
throw new IllegalArgumentException("G is null");
}
if (nodes == null) {
throw new IllegalArgumentException("nodes == null");
}
this.G = G;
pendingChildren = new Iterator[G.getMaxNumber() + 1];
init(G, nodes);
}
/**
* Constructor DFSFinishTimeIterator.
*
* @param G
* @throws NullPointerException if G is null
*/
public NumberedDFSDiscoverTimeIterator(NumberedGraph<T> G) throws NullPointerException {
this(G, G == null ? null : G.iterator());
}
/**
* Method getPendingChildren.
*
* @return Object
*/
@Override
protected Iterator<? extends T> getPendingChildren(T n) {
return pendingChildren[G.getNumber(n)];
}
/**
* Method setPendingChildren.
*
* @param v
* @param iterator
*/
@Override
protected void setPendingChildren(T v, Iterator<? extends T> iterator) {
pendingChildren[G.getNumber(v)] = iterator;
}
}