aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: 
aoqi@0: package com.sun.xml.internal.ws.policy;
aoqi@0: 
aoqi@0: import com.sun.xml.internal.ws.policy.privateutil.PolicyLogger;
aoqi@0: import java.util.Collection;
aoqi@0: import java.util.LinkedList;
aoqi@0: import java.util.List;
aoqi@0: import java.util.Queue;
aoqi@0: import com.sun.xml.internal.ws.policy.privateutil.LocalizationMessages;
aoqi@0: import com.sun.xml.internal.ws.policy.sourcemodel.wspolicy.NamespaceVersion;
aoqi@0: import java.util.ArrayList;
aoqi@0: 
aoqi@0: /**
aoqi@0:  * The instance of this class is intended to provide policy intersection mechanism.
aoqi@0:  *
aoqi@0:  * @author Marek Potociar (marek.potociar@sun.com)
aoqi@0:  */
aoqi@0: public final class PolicyIntersector {
aoqi@0:     static enum CompatibilityMode {
aoqi@0:         STRICT,
aoqi@0:         LAX
aoqi@0:     }
aoqi@0: 
aoqi@0:     private static final PolicyIntersector STRICT_INTERSECTOR = new PolicyIntersector(CompatibilityMode.STRICT);
aoqi@0:     private static final PolicyIntersector LAX_INTERSECTOR = new PolicyIntersector(CompatibilityMode.LAX);
aoqi@0:     private static final PolicyLogger LOGGER = PolicyLogger.getLogger(PolicyIntersector.class);
aoqi@0: 
aoqi@0:     private CompatibilityMode mode;
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Prevents direct instantiation of this class from outside
aoqi@0:      * @param intersectionMode intersection mode
aoqi@0:      */
aoqi@0:     private PolicyIntersector(CompatibilityMode intersectionMode) {
aoqi@0:         this.mode = intersectionMode;
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Returns a strict policy intersector that can be used to intersect group of policies.
aoqi@0:      *
aoqi@0:      * @return policy intersector instance.
aoqi@0:      */
aoqi@0:     public static PolicyIntersector createStrictPolicyIntersector() {
aoqi@0:         return PolicyIntersector.STRICT_INTERSECTOR;
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Returns a strict policy intersector that can be used to intersect group of policies.
aoqi@0:      *
aoqi@0:      * @return policy intersector instance.
aoqi@0:      */
aoqi@0:     public static PolicyIntersector createLaxPolicyIntersector() {
aoqi@0:         return PolicyIntersector.LAX_INTERSECTOR;
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Performs intersection on the input collection of policies and returns the resulting (intersected) policy. If input policy
aoqi@0:      * collection contains only a single policy instance, no intersection is performed and the instance is directly returned
aoqi@0:      * as a method call result.
aoqi@0:      *
aoqi@0:      * @param policies collection of policies to be intersected. Must not be {@code null} nor empty, otherwise exception is thrown.
aoqi@0:      * @return intersected policy as a result of perfromed policy intersection. A {@code null} value is never returned.
aoqi@0:      *
aoqi@0:      * @throws IllegalArgumentException in case {@code policies} argument is either {@code null} or empty collection.
aoqi@0:      */
aoqi@0:     public Policy intersect(final Policy... policies) {
aoqi@0:         if (policies == null || policies.length == 0) {
aoqi@0:             throw LOGGER.logSevereException(new IllegalArgumentException(LocalizationMessages.WSP_0056_NEITHER_NULL_NOR_EMPTY_POLICY_COLLECTION_EXPECTED()));
aoqi@0:         } else if (policies.length == 1) {
aoqi@0:             return policies[0];
aoqi@0:         }
aoqi@0: 
aoqi@0:         // check for "null" and "empty" policy: if such policy is found return "null" policy,
aoqi@0:         // or if all policies are "empty", return "empty" policy
aoqi@0:         boolean found = false;
aoqi@0:         boolean allPoliciesEmpty = true;
aoqi@0:         NamespaceVersion latestVersion = null;
aoqi@0:         for (Policy tested : policies) {
aoqi@0:             if (tested.isEmpty()) {
aoqi@0:                 found = true;
aoqi@0:             } else {
aoqi@0:                 if (tested.isNull()) {
aoqi@0:                     found = true;
aoqi@0:                 }
aoqi@0:                 allPoliciesEmpty = false;
aoqi@0:             }
aoqi@0:             if (latestVersion == null) {
aoqi@0:                 latestVersion = tested.getNamespaceVersion();
aoqi@0:             } else if (latestVersion.compareTo(tested.getNamespaceVersion()) < 0) {
aoqi@0:                 latestVersion = tested.getNamespaceVersion();
aoqi@0:             }
aoqi@0: 
aoqi@0:             if (found && !allPoliciesEmpty) {
aoqi@0:                 return Policy.createNullPolicy(latestVersion, null, null);
aoqi@0:             }
aoqi@0:         }
aoqi@0:         latestVersion = (latestVersion != null) ? latestVersion : NamespaceVersion.getLatestVersion();
aoqi@0:         if (allPoliciesEmpty) {
aoqi@0:             return Policy.createEmptyPolicy(latestVersion, null, null);
aoqi@0:         }
aoqi@0: 
aoqi@0:         // simple tests didn't lead to final answer => let's performe some intersecting ;)
aoqi@0:         final List<AssertionSet> finalAlternatives = new LinkedList<AssertionSet>(policies[0].getContent());
aoqi@0:         final Queue<AssertionSet> testedAlternatives = new LinkedList<AssertionSet>();
aoqi@0:         final List<AssertionSet> alternativesToMerge = new ArrayList<AssertionSet>(2);
aoqi@0:         for (int i = 1; i < policies.length; i++) {
aoqi@0:             final Collection<AssertionSet> currentAlternatives = policies[i].getContent();
aoqi@0: 
aoqi@0:             testedAlternatives.clear();
aoqi@0:             testedAlternatives.addAll(finalAlternatives);
aoqi@0:             finalAlternatives.clear();
aoqi@0: 
aoqi@0:             AssertionSet testedAlternative;
aoqi@0:             while ((testedAlternative = testedAlternatives.poll()) != null) {
aoqi@0:                 for (AssertionSet currentAlternative : currentAlternatives) {
aoqi@0:                     if (testedAlternative.isCompatibleWith(currentAlternative, this.mode)) {
aoqi@0:                         alternativesToMerge.add(testedAlternative);
aoqi@0:                         alternativesToMerge.add(currentAlternative);
aoqi@0:                         finalAlternatives.add(AssertionSet.createMergedAssertionSet(alternativesToMerge));
aoqi@0:                         alternativesToMerge.clear();
aoqi@0:                     }
aoqi@0:                 }
aoqi@0:             }
aoqi@0:         }
aoqi@0: 
aoqi@0:         return Policy.createPolicy(latestVersion, null, null, finalAlternatives);
aoqi@0:     }
aoqi@0: }