org.codehaus.groovy.grails.plugins.springsecurity.WebExpressionVoter.java Source code

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

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/* Copyright 2006-2012 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;

import java.util.Collection;

import org.springframework.expression.EvaluationContext;
import org.springframework.security.access.AccessDecisionVoter;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.access.expression.ExpressionUtils;
import org.springframework.security.core.Authentication;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.expression.WebSecurityExpressionHandler;
import org.springframework.util.Assert;

/**
 * Based on the class of the same name in Spring Security which uses the
 * package-default WebExpressionConfigAttribute.
 *
 * @author <a href='mailto:burt@burtbeckwith.com'>Burt Beckwith</a>
 */
public class WebExpressionVoter implements AccessDecisionVoter {

    private WebSecurityExpressionHandler _expressionHandler;

    /**
     * {@inheritDoc}
     * @see org.springframework.security.access.AccessDecisionVoter#vote(
     *    org.springframework.security.core.Authentication, java.lang.Object, java.util.Collection)
     */
    public int vote(final Authentication authentication, final Object object,
            final Collection<ConfigAttribute> attributes) {

        Assert.notNull(authentication, "authentication cannot be null");
        Assert.notNull(object, "object cannot be null");
        Assert.notNull(attributes, "attributes cannot be null");

        WebExpressionConfigAttribute weca = findConfigAttribute(attributes);
        if (weca == null) {
            return ACCESS_ABSTAIN;
        }

        FilterInvocation fi = (FilterInvocation) object;
        EvaluationContext ctx = _expressionHandler.createEvaluationContext(authentication, fi);

        return ExpressionUtils.evaluateAsBoolean(weca.getAuthorizeExpression(), ctx) ? ACCESS_GRANTED
                : ACCESS_DENIED;
    }

    private WebExpressionConfigAttribute findConfigAttribute(final Collection<ConfigAttribute> attributes) {
        for (ConfigAttribute attribute : attributes) {
            if (attribute instanceof WebExpressionConfigAttribute) {
                return (WebExpressionConfigAttribute) attribute;
            }
        }
        return null;
    }

    /**
     * {@inheritDoc}
     * @see org.springframework.security.access.AccessDecisionVoter#supports(
     *    org.springframework.security.access.ConfigAttribute)
     */
    public boolean supports(ConfigAttribute attribute) {
        return attribute instanceof WebExpressionConfigAttribute;
    }

    /**
     * {@inheritDoc}
     * @see org.springframework.security.access.AccessDecisionVoter#supports(java.lang.Class)
     */
    public boolean supports(Class<?> clazz) {
        return clazz.isAssignableFrom(FilterInvocation.class);
    }

    /**
     * Dependency injection for the expression handler.
     * @param expressionHandler the handler
     */
    public void setExpressionHandler(final WebSecurityExpressionHandler expressionHandler) {
        _expressionHandler = expressionHandler;
    }
}