src/main/java/org/apache/neethi/util/PolicyComparator.java

/**
 * 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.neethi.util;

import java.util.List;

import org.apache.neethi.All;
import org.apache.neethi.Assertion;
import org.apache.neethi.ExactlyOne;
import org.apache.neethi.Policy;
import org.apache.neethi.PolicyComponent;

/**
 * A Utility class that provides methods the check the equality of
 * PolicyComponents.
 * 
 */
public final class PolicyComparator {
    private PolicyComparator() {
        //utility class
    }

    /**
     * Returns {@code true} if the two policies have the same semantics
     * 
     * @param arg1
     *            a Policy
     * @param arg2
     *            an another Policy
     * @return {@code true} if both policies have the same semantics
     */
    public static boolean compare(Policy arg1, Policy arg2) {
        
        // check Name attributes of each policies
        if (arg1.getName() != null) {
            
            if ((arg2.getName() == null) || !arg1.getName().equals(arg2.getName())) {
                return false;
            }
            
        } else {
            if (arg2.getName() != null) {
                return false;                
            }
        }
        // check the namespaces
        if (arg1.getNamespace() != null
            && !arg1.getNamespace().equals(arg2.getNamespace())) {
            return false;
        }
        // check Id attributes of each policies
        if (arg1.getId() != null) {
            
            if ((arg2.getId() == null) || !arg1.getId().equals(arg2.getId())) {
                return false;
            }
            
        } else {
            
            if (arg2.getId() != null) {
                return false;
            }
        }
        
        return compare(arg1.getPolicyComponents(), arg2.getPolicyComponents());
    }

    /**
     * Returns {@code true} if the two PolicyComponents have the same
     * semantics.
     * 
     * @param arg1
     *            a PolicyComponent
     * @param arg2
     *            an another PolicyComponent
     * @return {@code true} if both PolicyComponents have the same semantics
     */
    public static boolean compare(PolicyComponent arg1, PolicyComponent arg2) {
        if (!arg1.getClass().equals(arg2.getClass())) {
            return false;
        }

        if (arg1 instanceof Policy) {
            return compare((Policy) arg1, (Policy) arg2);

        } else if (arg1 instanceof All) {
            return compare((All) arg1, (All) arg2);

        } else if (arg1 instanceof ExactlyOne) {
            return compare((ExactlyOne) arg1, (ExactlyOne) arg2);

        } else if (arg1 instanceof Assertion) {
            return compare((Assertion) arg1, (Assertion) arg2);

        } else {
            // TODO should I throw an exception ..
        }

        return false;
    }

    public static boolean compare(All arg1, All arg2) {
        return compare(arg1.getPolicyComponents(), arg2.getPolicyComponents());
    }

    public static boolean compare(ExactlyOne arg1, ExactlyOne arg2) {
        return compare(arg1.getPolicyComponents(), arg2.getPolicyComponents());
    }

    public static boolean compare(Assertion arg1, Assertion arg2) {
        if (!(arg1.getName().equals(arg2.getName()))) {
            return false;
        }
        return true;
    }

    private static boolean compare(List<PolicyComponent> arg1, List<PolicyComponent> arg2) {
        if (arg1.size() != arg2.size()) {
            return false;
        }

        
        for (PolicyComponent assertion1 : arg1) {
            boolean match = false;
            for (PolicyComponent assertion2 : arg2) {
                if (compare(assertion1, assertion2)) {
                    match = true;
                    break;
                }
            }

            if (!match) {
                return false;
            }
        }
        return true;
    }
}