/*
 * Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.imageio.spi;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

A node in a directed graph. In addition to an arbitrary Object containing user data associated with the node, each node maintains a Sets of nodes which are pointed to by the current node (available from getOutNodes). The in-degree of the node (that is, number of nodes that point to the current node) may be queried.
/** * A node in a directed graph. In addition to an arbitrary * {@code Object} containing user data associated with the node, * each node maintains a {@code Set}s of nodes which are pointed * to by the current node (available from {@code getOutNodes}). * The in-degree of the node (that is, number of nodes that point to * the current node) may be queried. * */
class DigraphNode<E> implements Cloneable, Serializable { private static final long serialVersionUID = 5308261378582246841L;
The data associated with this node.
/** The data associated with this node. */
protected E data;
A Set of neighboring nodes pointed to by this node.
/** * A {@code Set} of neighboring nodes pointed to by this * node. */
protected Set<DigraphNode<E>> outNodes = new HashSet<>();
The in-degree of the node.
/** The in-degree of the node. */
protected int inDegree = 0;
A Set of neighboring nodes that point to this node.
/** * A {@code Set} of neighboring nodes that point to this * node. */
private Set<DigraphNode<E>> inNodes = new HashSet<>(); public DigraphNode(E data) { this.data = data; }
Returns the Object referenced by this node.
/** Returns the {@code Object} referenced by this node. */
public E getData() { return data; }
Returns an Iterator containing the nodes pointed to by this node.
/** * Returns an {@code Iterator} containing the nodes pointed * to by this node. */
public Iterator<DigraphNode<E>> getOutNodes() { return outNodes.iterator(); }
Adds a directed edge to the graph. The outNodes list of this node is updated and the in-degree of the other node is incremented.
Params:
  • node – a DigraphNode.
Returns:true if the node was not previously the target of an edge.
/** * Adds a directed edge to the graph. The outNodes list of this * node is updated and the in-degree of the other node is incremented. * * @param node a {@code DigraphNode}. * * @return {@code true} if the node was not previously the * target of an edge. */
public boolean addEdge(DigraphNode<E> node) { if (outNodes.contains(node)) { return false; } outNodes.add(node); node.inNodes.add(this); node.incrementInDegree(); return true; }
Returns true if an edge exists between this node and the given node.
Params:
  • node – a DigraphNode.
Returns:true if the node is the target of an edge.
/** * Returns {@code true} if an edge exists between this node * and the given node. * * @param node a {@code DigraphNode}. * * @return {@code true} if the node is the target of an edge. */
public boolean hasEdge(DigraphNode<E> node) { return outNodes.contains(node); }
Removes a directed edge from the graph. The outNodes list of this node is updated and the in-degree of the other node is decremented.
Returns:true if the node was previously the target of an edge.
/** * Removes a directed edge from the graph. The outNodes list of this * node is updated and the in-degree of the other node is decremented. * * @return {@code true} if the node was previously the target * of an edge. */
public boolean removeEdge(DigraphNode<E> node) { if (!outNodes.contains(node)) { return false; } outNodes.remove(node); node.inNodes.remove(this); node.decrementInDegree(); return true; }
Removes this node from the graph, updating neighboring nodes appropriately.
/** * Removes this node from the graph, updating neighboring nodes * appropriately. */
public void dispose() { Object[] inNodesArray = inNodes.toArray(); for(int i=0; i<inNodesArray.length; i++) { @SuppressWarnings("unchecked") DigraphNode<E> node = (DigraphNode<E>)inNodesArray[i]; node.removeEdge(this); } Object[] outNodesArray = outNodes.toArray(); for(int i=0; i<outNodesArray.length; i++) { @SuppressWarnings("unchecked") DigraphNode<E> node = (DigraphNode<E>)outNodesArray[i]; removeEdge(node); } }
Returns the in-degree of this node.
/** Returns the in-degree of this node. */
public int getInDegree() { return inDegree; }
Increments the in-degree of this node.
/** Increments the in-degree of this node. */
private void incrementInDegree() { ++inDegree; }
Decrements the in-degree of this node.
/** Decrements the in-degree of this node. */
private void decrementInDegree() { --inDegree; } }