Java tutorial
/** * Copyright 2002-2015 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. * See the License for the specific language governing permissions and * limitations under the License. */ package ch.rasc.wampspring.method; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.Comparator; import java.util.Iterator; import java.util.LinkedHashSet; import java.util.List; import java.util.Set; import org.springframework.messaging.Message; import org.springframework.messaging.handler.AbstractMessageCondition; import org.springframework.messaging.handler.MessageCondition; import org.springframework.util.Assert; import org.springframework.util.PathMatcher; import ch.rasc.wampspring.message.WampMessage; /** * A {@link MessageCondition} for matching the destination of a Message against one or * more destination patterns using a {@link PathMatcher}. * * @author Rossen Stoyanchev * @author Ralph Schaer */ public class DestinationPatternsMessageCondition extends AbstractMessageCondition<DestinationPatternsMessageCondition> { private final Set<String> patterns; private final PathMatcher pathMatcher; /** * Alternative constructor accepting a custom PathMatcher. * @param patterns the URL patterns to use; if 0, the condition will match to every * request. * @param pathMatcher the PathMatcher to use */ public DestinationPatternsMessageCondition(String[] patterns, PathMatcher pathMatcher) { this(asList(patterns), pathMatcher); } private DestinationPatternsMessageCondition(Collection<String> patterns, PathMatcher pathMatcher) { Assert.notNull(pathMatcher, "pathMatcher is required"); this.pathMatcher = pathMatcher; this.patterns = Collections.unmodifiableSet(new LinkedHashSet<>(patterns)); } private static List<String> asList(String... patterns) { return patterns != null ? Arrays.asList(patterns) : Collections.<String>emptyList(); } public Set<String> getPatterns() { return this.patterns; } @Override protected Collection<String> getContent() { return this.patterns; } @Override protected String getToStringInfix() { return " || "; } /** * Returns a new instance with URL patterns from the current instance ("this") and the * "other" instance as follows: * <ul> * <li>If there are patterns in both instances, combine the patterns in "this" with * the patterns in "other" using * {@link org.springframework.util.PathMatcher#combine(String, String)}. * <li>If only one instance has patterns, use them. * <li>If neither instance has patterns, use an empty String (i.e. ""). * </ul> */ @Override public DestinationPatternsMessageCondition combine(DestinationPatternsMessageCondition other) { Set<String> result = new LinkedHashSet<>(); if (!this.patterns.isEmpty() && !other.patterns.isEmpty()) { for (String pattern1 : this.patterns) { for (String pattern2 : other.patterns) { result.add(this.pathMatcher.combine(pattern1, pattern2)); } } } else if (!this.patterns.isEmpty()) { result.addAll(this.patterns); } else if (!other.patterns.isEmpty()) { result.addAll(other.patterns); } else { result.add(""); } return new DestinationPatternsMessageCondition(result, this.pathMatcher); } /** * Check if any of the patterns match the given Message destination and return an * instance that is guaranteed to contain matching patterns, sorted via * {@link org.springframework.util.PathMatcher#getPatternComparator(String)}. * @param message the message to match to * @return the same instance if the condition contains no patterns; or a new condition * with sorted matching patterns; or {@code null} either if a destination can not be * extracted or there is no match */ @Override public DestinationPatternsMessageCondition getMatchingCondition(Message<?> message) { WampMessage wampMessage = (WampMessage) message; String destination = wampMessage.getDestination(); if (destination == null) { return null; } if (this.patterns.isEmpty()) { return this; } List<String> matches = new ArrayList<>(); for (String pattern : this.patterns) { if (pattern.equals(destination) || this.pathMatcher.match(pattern, destination) || "**".equals(destination)) { matches.add(pattern); } } if (matches.isEmpty()) { return null; } Collections.sort(matches, this.pathMatcher.getPatternComparator(destination)); return new DestinationPatternsMessageCondition(matches, this.pathMatcher); } /** * Compare the two conditions based on the destination patterns they contain. Patterns * are compared one at a time, from top to bottom via * {@link org.springframework.util.PathMatcher#getPatternComparator(String)}. If all * compared patterns match equally, but one instance has more patterns, it is * considered a closer match. * <p> * It is assumed that both instances have been obtained via * {@link #getMatchingCondition(Message)} to ensure they contain only patterns that * match the request and are sorted with the best matches on top. */ @Override public int compareTo(DestinationPatternsMessageCondition other, Message<?> message) { WampMessage wampMessage = (WampMessage) message; String destination = wampMessage.getDestination(); Comparator<String> patternComparator = this.pathMatcher.getPatternComparator(destination); Iterator<String> iterator = this.patterns.iterator(); Iterator<String> iteratorOther = other.patterns.iterator(); while (iterator.hasNext() && iteratorOther.hasNext()) { int result = patternComparator.compare(iterator.next(), iteratorOther.next()); if (result != 0) { return result; } } if (iterator.hasNext()) { return -1; } else if (iteratorOther.hasNext()) { return 1; } else { return 0; } } }