org.springframework.messaging.core.CachingDestinationResolverProxy 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
*
* https://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.core;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* {@link DestinationResolver} implementation that proxies a target DestinationResolver,
* caching its {@link #resolveDestination} results. Such caching is particularly useful
* if the destination resolving process is expensive (e.g. the destination has to be
* resolved through an external system) and the resolution results are stable anyway.
*
* @author Agim Emruli
* @author Juergen Hoeller
* @since 4.1
* @param the destination type
* @see DestinationResolver#resolveDestination
*/
public class CachingDestinationResolverProxy implements DestinationResolver, InitializingBean {
private final Map resolvedDestinationCache = new ConcurrentHashMap<>();
@Nullable
private DestinationResolver targetDestinationResolver;
/**
* Create a new CachingDestinationResolverProxy, setting the target DestinationResolver
* through the {@link #setTargetDestinationResolver} bean property.
*/
public CachingDestinationResolverProxy() {
}
/**
* Create a new CachingDestinationResolverProxy using the given target
* DestinationResolver to actually resolve destinations.
* @param targetDestinationResolver the target DestinationResolver to delegate to
*/
public CachingDestinationResolverProxy(DestinationResolver targetDestinationResolver) {
Assert.notNull(targetDestinationResolver, "Target DestinationResolver must not be null");
this.targetDestinationResolver = targetDestinationResolver;
}
/**
* Set the target DestinationResolver to delegate to.
*/
public void setTargetDestinationResolver(DestinationResolver targetDestinationResolver) {
this.targetDestinationResolver = targetDestinationResolver;
}
@Override
public void afterPropertiesSet() {
if (this.targetDestinationResolver == null) {
throw new IllegalArgumentException("Property 'targetDestinationResolver' is required");
}
}
/**
* Resolves and caches destinations if successfully resolved by the target
* DestinationResolver implementation.
* @param name the destination name to be resolved
* @return the currently resolved destination or an already cached destination
* @throws DestinationResolutionException if the target DestinationResolver
* reports an error during destination resolution
*/
@Override
public D resolveDestination(String name) throws DestinationResolutionException {
D destination = this.resolvedDestinationCache.get(name);
if (destination == null) {
Assert.state(this.targetDestinationResolver != null, "No target DestinationResolver set");
destination = this.targetDestinationResolver.resolveDestination(name);
this.resolvedDestinationCache.put(name, destination);
}
return destination;
}
}