org.codehaus.groovy.grails.plugins.springsecurity.acl.ProxyAwareDelegatingMethodSecurityMetadataSource.java Source code

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Here is the source code for org.codehaus.groovy.grails.plugins.springsecurity.acl.ProxyAwareDelegatingMethodSecurityMetadataSource.java

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/* Copyright 2006-2010 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.codehaus.groovy.grails.plugins.springsecurity.acl;

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.beans.factory.InitializingBean;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.access.method.AbstractMethodSecurityMetadataSource;
import org.springframework.security.access.method.MethodSecurityMetadataSource;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;

/**
 * Replacement for DelegatingMethodSecurityMetadataSource which is final.
 * <p/>
 * Makes two changes; unproxies classes, and treats an empty return value from
 * <code>MethodSecurityMetadataSource.getAttributes()</code> as equivalent to a
 * <code>null</code> return since an empty return stops the loop and another
 * source might have attributes.
 *
 * @author Ben Alex
 * @author Luke Taylor
 * @author <a href='mailto:burt@burtbeckwith.com'>Burt Beckwith</a>
 */
public class ProxyAwareDelegatingMethodSecurityMetadataSource extends AbstractMethodSecurityMetadataSource
        implements InitializingBean {

    private final static List<ConfigAttribute> NULL_CONFIG_ATTRIBUTE = Collections.emptyList();

    private List<MethodSecurityMetadataSource> _methodSecurityMetadataSources;
    private final Map<DefaultCacheKey, Collection<ConfigAttribute>> _cache = new HashMap<DefaultCacheKey, Collection<ConfigAttribute>>();

    /**
     * {@inheritDoc}
     * @see org.springframework.security.access.method.MethodSecurityMetadataSource#getAttributes(
     *    java.lang.reflect.Method, java.lang.Class)
     */
    public Collection<ConfigAttribute> getAttributes(final Method m, final Class<?> tc) {

        Method method = ProxyUtils.unproxy(m);
        Class<?> targetClass = ProxyUtils.unproxy(tc);

        DefaultCacheKey cacheKey = new DefaultCacheKey(method, targetClass);
        synchronized (_cache) {
            Collection<ConfigAttribute> cached = _cache.get(cacheKey);
            // Check for canonical value indicating there is no config attribute,
            if (cached == NULL_CONFIG_ATTRIBUTE) {
                return null;
            }

            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) {
                _cache.put(cacheKey, NULL_CONFIG_ATTRIBUTE);
                return null;
            }

            if (logger.isDebugEnabled()) {
                logger.debug("Adding security method [" + cacheKey + "] with attributes " + attributes);
            }

            _cache.put(cacheKey, attributes);

            return attributes;
        }
    }

    /**
     * {@inheritDoc}
     * @see org.springframework.security.access.SecurityMetadataSource#getAllConfigAttributes()
     */
    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;
    }

    /**
     * Dependency injection for the sources.
     * @param sources  the sources
     */
    public void setMethodSecurityMetadataSources(final List<MethodSecurityMetadataSource> sources) {
        _methodSecurityMetadataSources = sources;
    }

    /**
     * {@inheritDoc}
     * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
     */
    public void afterPropertiesSet() {
        Assert.notEmpty(_methodSecurityMetadataSources, "A list of MethodSecurityMetadataSources is required");
    }

    private static class DefaultCacheKey {
        private final Method _method;
        private final Class<?> _targetClass;

        DefaultCacheKey(final Method method, final Class<?> targetClass) {
            _method = method;
            _targetClass = targetClass;
        }

        @Override
        public boolean equals(final Object other) {
            if (this == other) {
                return true;
            }
            if (!(other instanceof DefaultCacheKey)) {
                return false;
            }
            DefaultCacheKey otherKey = (DefaultCacheKey) other;
            return (_method.equals(otherKey._method)
                    && ObjectUtils.nullSafeEquals(_targetClass, otherKey._targetClass));
        }

        @Override
        public int hashCode() {
            return _method.hashCode() * 21 + (_targetClass != null ? _targetClass.hashCode() : 0);
        }

        @Override
        public String toString() {
            return "CacheKey[" + (_targetClass == null ? "-" : _targetClass.getName()) + "; " + _method + "]";
        }
    }
}