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package com.sun.xml.internal.ws.policy;
import com.sun.xml.internal.ws.policy.privateutil.PolicyLogger;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import com.sun.xml.internal.ws.policy.privateutil.LocalizationMessages;
import com.sun.xml.internal.ws.policy.sourcemodel.wspolicy.NamespaceVersion;
import java.util.ArrayList;
/**
* The instance of this class is intended to provide policy intersection mechanism.
*
* @author Marek Potociar (marek.potociar@sun.com)
*/
public final class PolicyIntersector {
static enum CompatibilityMode {
STRICT,
LAX
}
private static final PolicyIntersector STRICT_INTERSECTOR = new PolicyIntersector(CompatibilityMode.STRICT);
private static final PolicyIntersector LAX_INTERSECTOR = new PolicyIntersector(CompatibilityMode.LAX);
private static final PolicyLogger LOGGER = PolicyLogger.getLogger(PolicyIntersector.class);
private CompatibilityMode mode;
/**
* Prevents direct instantiation of this class from outside
* @param intersectionMode intersection mode
*/
private PolicyIntersector(CompatibilityMode intersectionMode) {
this.mode = intersectionMode;
}
/**
* Returns a strict policy intersector that can be used to intersect group of policies.
*
* @return policy intersector instance.
*/
public static PolicyIntersector createStrictPolicyIntersector() {
return PolicyIntersector.STRICT_INTERSECTOR;
}
/**
* Returns a strict policy intersector that can be used to intersect group of policies.
*
* @return policy intersector instance.
*/
public static PolicyIntersector createLaxPolicyIntersector() {
return PolicyIntersector.LAX_INTERSECTOR;
}
/**
* Performs intersection on the input collection of policies and returns the resulting (intersected) policy. If input policy
* collection contains only a single policy instance, no intersection is performed and the instance is directly returned
* as a method call result.
*
* @param policies collection of policies to be intersected. Must not be {@code null} nor empty, otherwise exception is thrown.
* @return intersected policy as a result of perfromed policy intersection. A {@code null} value is never returned.
*
* @throws IllegalArgumentException in case {@code policies} argument is either {@code null} or empty collection.
*/
public Policy intersect(final Policy... policies) {
if (policies == null || policies.length == 0) {
throw LOGGER.logSevereException(new IllegalArgumentException(LocalizationMessages.WSP_0056_NEITHER_NULL_NOR_EMPTY_POLICY_COLLECTION_EXPECTED()));
} else if (policies.length == 1) {
return policies[0];
}
// check for "null" and "empty" policy: if such policy is found return "null" policy,
// or if all policies are "empty", return "empty" policy
boolean found = false;
boolean allPoliciesEmpty = true;
NamespaceVersion latestVersion = null;
for (Policy tested : policies) {
if (tested.isEmpty()) {
found = true;
} else {
if (tested.isNull()) {
found = true;
}
allPoliciesEmpty = false;
}
if (latestVersion == null) {
latestVersion = tested.getNamespaceVersion();
} else if (latestVersion.compareTo(tested.getNamespaceVersion()) < 0) {
latestVersion = tested.getNamespaceVersion();
}
if (found && !allPoliciesEmpty) {
return Policy.createNullPolicy(latestVersion, null, null);
}
}
latestVersion = (latestVersion != null) ? latestVersion : NamespaceVersion.getLatestVersion();
if (allPoliciesEmpty) {
return Policy.createEmptyPolicy(latestVersion, null, null);
}
// simple tests didn't lead to final answer => let's performe some intersecting ;)
final List<AssertionSet> finalAlternatives = new LinkedList<AssertionSet>(policies[0].getContent());
final Queue<AssertionSet> testedAlternatives = new LinkedList<AssertionSet>();
final List<AssertionSet> alternativesToMerge = new ArrayList<AssertionSet>(2);
for (int i = 1; i < policies.length; i++) {
final Collection<AssertionSet> currentAlternatives = policies[i].getContent();
testedAlternatives.clear();
testedAlternatives.addAll(finalAlternatives);
finalAlternatives.clear();
AssertionSet testedAlternative;
while ((testedAlternative = testedAlternatives.poll()) != null) {
for (AssertionSet currentAlternative : currentAlternatives) {
if (testedAlternative.isCompatibleWith(currentAlternative, this.mode)) {
alternativesToMerge.add(testedAlternative);
alternativesToMerge.add(currentAlternative);
finalAlternatives.add(AssertionSet.createMergedAssertionSet(alternativesToMerge));
alternativesToMerge.clear();
}
}
}
}
return Policy.createPolicy(latestVersion, null, null, finalAlternatives);
}
}