org.springframework.messaging.handler.DestinationPatternsMessageCondition Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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 org.springframework.messaging.handler;
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.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.util.AntPathMatcher;
import org.springframework.util.PathMatcher;
import org.springframework.util.StringUtils;
/**
* A {@link MessageCondition} for matching the destination of a Message
* against one or more destination patterns using a {@link PathMatcher}.
*
* @author Rossen Stoyanchev
* @since 4.0
*/
public class DestinationPatternsMessageCondition
extends AbstractMessageCondition {
/**
* The name of the "lookup destination" header.
*/
public static final String LOOKUP_DESTINATION_HEADER = "lookupDestination";
private final Set patterns;
private final PathMatcher pathMatcher;
/**
* Creates a new instance with the given destination patterns.
* Each pattern that is not empty and does not start with "/" is prepended with "/".
* @param patterns 0 or more URL patterns; if 0 the condition will match to every request.
*/
public DestinationPatternsMessageCondition(String... patterns) {
this(patterns, null);
}
/**
* 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, @Nullable PathMatcher pathMatcher) {
this(Arrays.asList(patterns), pathMatcher);
}
private DestinationPatternsMessageCondition(Collection patterns, @Nullable PathMatcher pathMatcher) {
this.pathMatcher = (pathMatcher != null ? pathMatcher : new AntPathMatcher());
this.patterns = Collections.unmodifiableSet(prependLeadingSlash(patterns, this.pathMatcher));
}
private static Set prependLeadingSlash(Collection patterns, PathMatcher pathMatcher) {
boolean slashSeparator = pathMatcher.combine("a", "a").equals("a/a");
Set result = new LinkedHashSet<>(patterns.size());
for (String pattern : patterns) {
if (slashSeparator && StringUtils.hasLength(pattern) && !pattern.startsWith("/")) {
pattern = "/" + pattern;
}
result.add(pattern);
}
return result;
}
public Set getPatterns() {
return this.patterns;
}
@Override
protected Collection 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:
*
* - 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)}.
*
- If only one instance has patterns, use them.
*
- If neither instance has patterns, use an empty String (i.e. "").
*
*/
@Override
public DestinationPatternsMessageCondition combine(DestinationPatternsMessageCondition other) {
Set 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
@Nullable
public DestinationPatternsMessageCondition getMatchingCondition(Message message) {
String destination = (String) message.getHeaders().get(LOOKUP_DESTINATION_HEADER);
if (destination == null) {
return null;
}
if (this.patterns.isEmpty()) {
return this;
}
List matches = new ArrayList<>();
for (String pattern : this.patterns) {
if (pattern.equals(destination) || this.pathMatcher.match(pattern, destination)) {
matches.add(pattern);
}
}
if (matches.isEmpty()) {
return null;
}
matches.sort(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.
* 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) {
String destination = (String) message.getHeaders().get(LOOKUP_DESTINATION_HEADER);
if (destination == null) {
return 0;
}
Comparator patternComparator = this.pathMatcher.getPatternComparator(destination);
Iterator iterator = this.patterns.iterator();
Iterator 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;
}
}
}