/*
* Copyright 2002-2016 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.security.access.method;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
/**
* Automatically tries a series of method definition sources, relying on the first source
* of metadata that provides a non-null/non-empty response. Provides automatic caching of
* the retrieved metadata.
*
* @author Ben Alex
* @author Luke Taylor
*/
public final class DelegatingMethodSecurityMetadataSource extends
AbstractMethodSecurityMetadataSource {
private final static List<ConfigAttribute> NULL_CONFIG_ATTRIBUTE = Collections
.emptyList();
private final List<MethodSecurityMetadataSource> methodSecurityMetadataSources;
private final Map<DefaultCacheKey, Collection<ConfigAttribute>> attributeCache = new HashMap<DefaultCacheKey, Collection<ConfigAttribute>>();
// ~ Constructor
// ====================================================================================================
public DelegatingMethodSecurityMetadataSource(
List<MethodSecurityMetadataSource> methodSecurityMetadataSources) {
Assert.notNull(methodSecurityMetadataSources,
"MethodSecurityMetadataSources cannot be null");
this.methodSecurityMetadataSources = methodSecurityMetadataSources;
}
// ~ Methods
// ========================================================================================================
public Collection<ConfigAttribute> getAttributes(Method method, Class<?> targetClass) {
DefaultCacheKey cacheKey = new DefaultCacheKey(method, targetClass);
synchronized (attributeCache) {
Collection<ConfigAttribute> cached = attributeCache.get(cacheKey);
// Check for canonical value indicating there is no config attribute,
if (cached != null) {
return cached;
}
// No cached value, so query the sources to find a result
Collection<ConfigAttribute> attributes = null;
for (MethodSecurityMetadataSource s : methodSecurityMetadataSources) {
attributes = s.getAttributes(method, targetClass);
if (attributes != null && !attributes.isEmpty()) {
break;
}
}
// Put it in the cache.
if (attributes == null || attributes.isEmpty()) {
this.attributeCache.put(cacheKey, NULL_CONFIG_ATTRIBUTE);
return NULL_CONFIG_ATTRIBUTE;
}
if (logger.isDebugEnabled()) {
logger.debug("Caching method [" + cacheKey + "] with attributes "
+ attributes);
}
this.attributeCache.put(cacheKey, attributes);
return attributes;
}
}
public Collection<ConfigAttribute> getAllConfigAttributes() {
Set<ConfigAttribute> set = new HashSet<ConfigAttribute>();
for (MethodSecurityMetadataSource s : methodSecurityMetadataSources) {
Collection<ConfigAttribute> attrs = s.getAllConfigAttributes();
if (attrs != null) {
set.addAll(attrs);
}
}
return set;
}
public List<MethodSecurityMetadataSource> getMethodSecurityMetadataSources() {
return methodSecurityMetadataSources;
}
// ~ Inner Classes
// ==================================================================================================
private static class DefaultCacheKey {
private final Method method;
private final Class<?> targetClass;
public DefaultCacheKey(Method method, Class<?> targetClass) {
this.method = method;
this.targetClass = targetClass;
}
public boolean equals(Object other) {
DefaultCacheKey otherKey = (DefaultCacheKey) other;
return (this.method.equals(otherKey.method) && ObjectUtils.nullSafeEquals(
this.targetClass, otherKey.targetClass));
}
public int hashCode() {
return this.method.hashCode() * 21
+ (this.targetClass != null ? this.targetClass.hashCode() : 0);
}
public String toString() {
return "CacheKey[" + (targetClass == null ? "-" : targetClass.getName())
+ "; " + method + "]";
}
}
}