/*
* Copyright 2008 the original author or authors.
- *
+ *
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
- *
+ *
* http://www.apache.org/licenses/LICENSE-2.0
- *
+ *
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
package org.wamblee.system.graph;
import java.util.ArrayList;
+import java.util.Iterator;
import java.util.List;
+
+/**
+ * Represents a graph consisting of nodes and edges.
+ *
+ * @author Erik Brakkee
+ */
public class Graph {
+ /**
+ * DOCUMENT ME!
+ */
+ private List<Node> nodes;
- private List<Node> _nodes;
- private List<Edge> _edges;
+ /**
+ * DOCUMENT ME!
+ */
+ private List<Edge> edges;
+/**
+ * Constructs the graph.
+ */
public Graph() {
- _nodes = new ArrayList<Node>();
- _edges = new ArrayList<Edge>();
+ nodes = new ArrayList<Node>();
+ edges = new ArrayList<Edge>();
}
+ /**
+ * Adds a node.
+ *
+ * @param aNode Node to add.
+ *
+ * @throws IllegalArgumentException In case the node already exists. Node
+ * equality is checked using <code>equals</code>.
+ */
public void addNode(Node aNode) {
- if (_nodes.contains(aNode)) {
+ if (nodes.contains(aNode)) {
throw new IllegalArgumentException("Node '" + aNode.getName()
- + "' already exists");
+ + "' already exists");
}
- _nodes.add(aNode);
+
+ nodes.add(aNode);
}
-
- public Node findNode(String aName) {
- for (Node node: _nodes) {
- if ( node.getName().equals(aName)) {
- return node;
+
+ /**
+ * Finds a node with the given name.
+ *
+ * @param aName Node name.
+ *
+ * @return Node or null if not found.
+ */
+ public Node findNode(String aName) {
+ for (Node node : nodes) {
+ if (node.getName().equals(aName)) {
+ return node;
}
}
- return null;
+
+ return null;
}
+ /**
+ * Removes a node.
+ *
+ * @param aNode Node to remove.
+ *
+ * @return True iff the node was removed.
+ *
+ * @throws IllegalArgumentException In case there are edges of which the
+ * node is a part.
+ */
public boolean removeNode(Node aNode) {
if (!findOutgoing(aNode).isEmpty() || !findIncoming(aNode).isEmpty()) {
throw new IllegalArgumentException("Cannot remove node '"
- + aNode.getName()
- + "' because it is connected to one or more edges");
+ + aNode.getName()
+ + "' because it is connected to one or more edges");
}
- return _nodes.remove(aNode);
+
+ return nodes.remove(aNode);
}
+ /**
+ * Adds a list of nodes.
+ *
+ * @param aNodes Nodes to add.
+ *
+ * @see #addNode(Node)
+ */
public void addNodes(List<Node> aNodes) {
for (Node node : aNodes) {
addNode(node);
}
}
+ /**
+ * Adds an edge.
+ *
+ * @param aEdge Edge to add.
+ *
+ * @throws IllegalArgumentException In case one of the nodes of the edges
+ * is not part of the graph or if the same edge (as determined by
+ * {@link #equals(Object)} is already a part of the graph.
+ */
public void addEdge(Edge aEdge) {
- if (_edges.contains(aEdge)) {
+ if (edges.contains(aEdge)) {
throw new IllegalArgumentException("Edge '" + aEdge
- + "' already exists");
+ + "' already exists");
}
- if (!_nodes.contains(aEdge.getFrom())) {
+
+ if (!nodes.contains(aEdge.getFrom())) {
throw new IllegalArgumentException("From node '" + aEdge.getFrom()
- + "' from edge '" + aEdge + "' is not part of the graph");
+ + "' from edge '" + aEdge + "' is not part of the graph");
}
- if (!_nodes.contains(aEdge.getTo())) {
+
+ if (!nodes.contains(aEdge.getTo())) {
throw new IllegalArgumentException("To node '" + aEdge.getTo()
- + "' from edge '" + aEdge + "' is not part of the graph");
+ + "' from edge '" + aEdge + "' is not part of the graph");
}
- _edges.add(aEdge);
+
+ edges.add(aEdge);
}
+ /**
+ * Removes an edge.
+ *
+ * @param aEdge Edge to remove.
+ *
+ * @return True if the edge was removed.
+ */
public boolean removeEdge(Edge aEdge) {
- return _edges.remove(aEdge);
+ return edges.remove(aEdge);
}
+ /**
+ * Adds a number of edges.
+ *
+ * @param aEdges Edges to add.
+ */
public void addEdges(List<Edge> aEdges) {
for (Edge edge : aEdges) {
addEdge(edge);
}
}
+ /**
+ * Gets the nodes.
+ *
+ * @return Copy of the list of nodes of the graph.
+ */
public List<Node> getNodes() {
- return new ArrayList<Node>(_nodes);
+ return new ArrayList<Node>(nodes);
}
+ /**
+ * Gets the edges.
+ *
+ * @return Copy of the list of edges of the graph.
+ */
public List<Edge> getEdges() {
- return new ArrayList<Edge>(_edges);
+ return new ArrayList<Edge>(edges);
}
+ /**
+ * Extends the graph with edges using an edge factory. All
+ * combinations of nodes are passed to the factory which creates
+ * additional edges.
+ *
+ * @param aFactory Edge factory.
+ */
public void extend(EdgeFactory aFactory) {
- for (Node from : _nodes) {
- for (Node to : _nodes) {
- _edges.addAll(aFactory.create(from, to));
+ for (Node from : nodes) {
+ for (Node to : nodes) {
+ edges.addAll(aFactory.create(from, to));
+ }
+ }
+ }
+
+ /**
+ * Applies a filter to the graph for removing elements.
+ *
+ * @param aFilter Filter to apply.
+ */
+ public void applyFilter(EdgeFilter aFilter) {
+ for (Iterator<Edge> edge = edges.iterator(); edge.hasNext();) {
+ if (aFilter.isViolated(edge.next())) {
+ edge.remove();
}
}
}
+ /**
+ * Finds all outgoing edges of a node. More specifically, finds
+ * all edges <code>e</code> for which <code>e.getFrom().getName() =
+ * aNode.getName()</code>.
+ *
+ * @param aNode Node for which to find outgoing edges.
+ *
+ * @return List of outgoing edges.
+ */
public List<Edge> findOutgoing(Node aNode) {
List<Edge> result = new ArrayList<Edge>();
- for (Edge edge : _edges) {
+
+ for (Edge edge : edges) {
if (edge.getFrom().getName().equals(aNode.getName())) {
result.add(edge);
}
}
+
return result;
}
+ /**
+ * Finds all incoming edges of a node. More specifically, finds
+ * all edges <code>e</code> for which <code>e.getTo().getName() =
+ * aNode.getName()</code>.
+ *
+ * @param aNode Node for which to find incoming edges.
+ *
+ * @return List of incoming edges.
+ */
public List<Edge> findIncoming(Node aNode) {
List<Edge> result = new ArrayList<Edge>();
- for (Edge edge : _edges) {
+
+ for (Edge edge : edges) {
if (edge.getTo().getName().equals(aNode.getName())) {
result.add(edge);
}
}
+
return result;
}
+ /**
+ * Implements a visitor design pattern. This loops over all nodes
+ * and all edges and invokes the appropriate visit methods on the visitor.
+ *
+ * @param aVisitor Visitor.
+ */
public void accept(Visitor aVisitor) {
List<Node> nodes = getNodes(); // copy to make sure the visitor can
- // modify the
- // list of nodes as part of the loop.
+ // modify the
+ // list of nodes as part of the loop.
+
List<Edge> edges = getEdges(); // copy ..... (see above).
for (Node node : nodes) {
aVisitor.visitNode(node);
}
+
for (Edge edge : edges) {
aVisitor.visitEdge(edge);
}
git://wamblee.org / utils / blobdiff