2 * Copyright 2005-2011 the original author or authors.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 package org.wamblee.xmlrouter.impl;
18 import java.util.ArrayList;
19 import java.util.Collection;
20 import java.util.Collections;
21 import java.util.HashSet;
22 import java.util.LinkedHashMap;
23 import java.util.List;
26 import java.util.concurrent.atomic.AtomicLong;
28 import org.wamblee.xmlrouter.common.Id;
29 import org.wamblee.xmlrouter.config.Transformation;
31 public class Transformations {
33 private AtomicLong sequenceNumber;
34 private Map<Long, Transformation> transformations;
35 private List<String> vertices;
36 private TransformationPath[][] matrix;
38 private Map<String, List<TransformationPath>> sequences;
40 public Transformations() {
41 sequenceNumber = new AtomicLong(1);
42 transformations = new LinkedHashMap<Long, Transformation>();
43 vertices = new ArrayList<String>();
44 matrix = new TransformationPath[0][0];
47 public Id<Transformation> addTransformation(Transformation aTransformation) {
48 long seqno = sequenceNumber.getAndIncrement();
49 Id<Transformation> id = new Id<Transformation>(seqno);
50 transformations.put(seqno,
51 new RobustTransformation(id, aTransformation));
52 computeTransformationSequences();
56 public Collection<String> getPossibleTargetTypes(String aType) {
57 int index = vertices.indexOf(aType);
58 Set<String> res = new HashSet<String>();
59 for (int j = 0; j < vertices.size(); j++) {
60 if (matrix[index][j] != null) {
61 String value = matrix[index][j].getToType();
73 * Gets the transformation path from A to B.
79 * @return Transformatkon path or null if not found.
81 public TransformationPath getPath(String aFrom, String aTo) {
82 int i = vertices.indexOf(aFrom);
84 if (aFrom.equals(aTo)) {
85 return new TransformationPath();
90 int j = vertices.indexOf(aTo);
97 private void computeTransformationSequences() {
98 vertices = new ArrayList<String>();
100 // Obtain possible starting points.
101 Set<String> v = new HashSet<String>();
102 for (Transformation transformation : transformations.values()) {
103 v.add(transformation.getFromType());
104 v.add(transformation.getToType());
109 matrix = new TransformationPath[vertices.size()][vertices.size()];
111 // Floyd's algorithm.
112 int nvertices = vertices.size();
113 for (int i = 0; i < nvertices; i++) {
114 matrix[i][i] = new TransformationPath();
116 for (Transformation transformation : transformations.values()) {
117 int from = vertices.indexOf(transformation.getFromType());
118 int to = vertices.indexOf(transformation.getToType());
119 TransformationPath path = new TransformationPath(transformation);
120 matrix[from][to] = path;
123 for (int k = 0; k < nvertices; k++) {
124 for (int i = 0; i < nvertices; i++) {
125 for (int j = 0; j < nvertices; j++) {
126 // if the path from i to j through k is shorter then the
127 // existing path then
129 int lij = getPathLength(i, j);
130 int lik = getPathLength(i, k);
131 int lkj = getPathLength(k, j);
132 if (lik + lkj < lij) {
133 matrix[i][j] = matrix[i][k].appendPath(matrix[k][j]);
140 private int getPathLength(int i, int j) {
141 // We use MAX_INT/3 as infinity. This ensures that the default integer
142 // comparison in Floyd's algorithm does not lead to overflow.
143 return matrix[i][j] == null ? Integer.MAX_VALUE / 3 : matrix[i][j]
147 public void removeTransformation(Id<Transformation> aId) {
148 transformations.remove(aId.getId());
149 computeTransformationSequences();
152 public Collection<Transformation> getTransformations() {
153 return Collections.unmodifiableCollection(transformations.values());
157 public String toString() {
158 StringBuffer buf = new StringBuffer();
159 buf.append("Transformations(");
160 int nvertices = vertices.size();
161 for (int i = 0; i < nvertices; i++) {
162 for (int j = 0; j < nvertices; j++) {
163 TransformationPath path = matrix[i][j];
165 buf.append(vertices.get(i));
167 buf.append(vertices.get(j));
175 return buf.toString();