| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with this |
| * work for additional information regarding copyright ownership. The ASF |
| * licenses this file to you 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.apache.bval.jsr303.resolver; |
| |
| import javax.validation.Path; |
| import javax.validation.TraversableResolver; |
| import java.lang.annotation.ElementType; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * Cache results of a delegated traversable resovler to optimize calls |
| * It works only for a single validate* call and should not be used if |
| * the TraversableResolver is accessed concurrently |
| * <p/> |
| * Date: 25.11.2009 <br/> |
| * Time: 13:56:18 <br/> |
| * |
| * @author Roman Stumm (based on the code of Emmanuel Bernard) |
| */ |
| public class CachingTraversableResolver implements TraversableResolver, CachingRelevant { |
| private TraversableResolver delegate; |
| private Map<CacheEntry, CacheEntry> cache = new HashMap<CacheEntry, CacheEntry>(); |
| |
| /** |
| * Convenience method to check whether caching is necessary on a given {@link TraversableResolver}. |
| * @param resolver to check |
| * @return true when a CachingTraversableResolver is to be used during validation |
| */ |
| public static boolean needsCaching(TraversableResolver resolver) { |
| // caching, if we do not know exactly |
| return !(resolver instanceof CachingRelevant) || |
| ((CachingRelevant) resolver).needsCaching(); |
| } |
| |
| /** |
| * Create a new CachingTraversableResolver instance. |
| * @param delegate |
| */ |
| public CachingTraversableResolver(TraversableResolver delegate) { |
| this.delegate = delegate; |
| } |
| |
| /** |
| * If necessary, return a caching wrapper for the specified {@link TraversableResolver}. |
| * @param traversableResolver |
| * @return {@link TraversableResolver} |
| * @see #needsCaching(TraversableResolver) |
| */ |
| public static TraversableResolver cacheFor(TraversableResolver traversableResolver) { |
| if (needsCaching(traversableResolver)) { |
| return new CachingTraversableResolver(traversableResolver); |
| } else { |
| return traversableResolver; |
| } |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean isReachable(Object traversableObject, Path.Node traversableProperty, |
| Class<?> rootBeanType, Path pathToTraversableObject, |
| ElementType elementType) { |
| CacheEntry currentLH = new CacheEntry(traversableObject, traversableProperty, |
| rootBeanType, pathToTraversableObject, elementType); |
| CacheEntry cachedLH = cache.get(currentLH); |
| if (cachedLH == null) { |
| currentLH.reachable = delegate.isReachable(traversableObject, traversableProperty, |
| rootBeanType, pathToTraversableObject, elementType); |
| cache.put(currentLH, currentLH); |
| cachedLH = currentLH; |
| } else if (cachedLH.reachable == null) { |
| cachedLH.reachable = delegate.isReachable(traversableObject, traversableProperty, |
| rootBeanType, pathToTraversableObject, elementType); |
| } |
| return cachedLH.reachable; |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean isCascadable(Object traversableObject, Path.Node traversableProperty, |
| Class<?> rootBeanType, Path pathToTraversableObject, |
| ElementType elementType) { |
| CacheEntry currentLH = new CacheEntry(traversableObject, traversableProperty, |
| rootBeanType, pathToTraversableObject, elementType); |
| CacheEntry cachedLH = cache.get(currentLH); |
| if (cachedLH == null) { |
| currentLH.cascadable = delegate.isCascadable(traversableObject, |
| traversableProperty, rootBeanType, pathToTraversableObject, elementType); |
| cache.put(currentLH, currentLH); |
| cachedLH = currentLH; |
| } else if (cachedLH.cascadable == null) { |
| cachedLH.cascadable = delegate.isCascadable(traversableObject, traversableProperty, |
| rootBeanType, pathToTraversableObject, elementType); |
| } |
| return cachedLH.cascadable; |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean needsCaching() { |
| return false; // I am the cache. Do not need cache for cache |
| } |
| |
| /** |
| * Entry in the cache. |
| */ |
| private static class CacheEntry { |
| private final Object object; |
| private final Path.Node node; |
| private final Class<?> type; |
| private final Path path; |
| private final ElementType elementType; |
| private final int hashCode; |
| |
| private Boolean reachable; |
| private Boolean cascadable; |
| |
| /** |
| * Create a new CacheEntry instance. |
| * @param traversableObject |
| * @param traversableProperty |
| * @param rootBeanType |
| * @param pathToTraversableObject |
| * @param elementType |
| */ |
| private CacheEntry(Object traversableObject, Path.Node traversableProperty, |
| Class<?> rootBeanType, Path pathToTraversableObject, |
| ElementType elementType) { |
| this.object = traversableObject; |
| this.node = traversableProperty; |
| this.type = rootBeanType; |
| this.path = pathToTraversableObject; |
| this.elementType = elementType; |
| this.hashCode = buildHashCode(); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) { |
| return true; |
| } |
| if (o == null || getClass() != o.getClass()) { |
| return false; |
| } |
| |
| CacheEntry that = (CacheEntry) o; |
| |
| return elementType == that.elementType && path.equals(that.path) && |
| type.equals(that.type) && |
| !(object != null ? !object.equals(that.object) : that.object != null) && |
| node.equals(that.node); |
| |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public int hashCode() { |
| return hashCode; |
| } |
| |
| private int buildHashCode() { |
| int result = object != null ? object.hashCode() : 0; |
| result = 31 * result + node.hashCode(); |
| result = 31 * result + type.hashCode(); |
| result = 31 * result + path.hashCode(); |
| result = 31 * result + elementType.hashCode(); |
| return result; |
| } |
| } |
| } |