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package com.sun.xml.ws.policy;
import com.sun.xml.ws.policy.privateutil.PolicyUtils;
import com.sun.xml.ws.policy.sourcemodel.wspolicy.NamespaceVersion;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedList;
/**
* Merge policies and return the effective policy.
*
* WS-PolicyAttachment defines a merge algorithm for WSDL 1.1 policy attachments.
*/
public final class PolicyMerger {
private static final PolicyMerger merger = new PolicyMerger();
/**
* This private constructor is to avoid direct class instantiation from outsied of the package
*/
private PolicyMerger() {
// nothing to instantiate
}
/**
* Factory method for obtaining thread-safe policy merger instance.
*
* @return policy merger instance.
*/
public static PolicyMerger getMerger() {
return merger;
}
/**
* Takes collection of policies and merges them into a single policy using algorithm described in
* WS-PolicyAttachment specification. None of the original policies in the collection are modified in
* any way.
*
* The newly created policy has an ID that is a concatentation of all merged policy IDs.
*
* @param policies collection of policies to be merged. The collection must not contain '{@code null}' elements!
* @return merged policy containing combination of policy alternatives stored in all input policies.
* If provided collection of policies is {@code null} or empty, returns {@code null}. If provided
* collection of policies contains only single policy, the policy is returned.
*/
public Policy merge(final Collection<Policy> policies) {
if (policies == null || policies.isEmpty()) {
return null;
} else if (policies.size() == 1) {
return policies.iterator().next();
}
final Collection<Collection<AssertionSet>> alternativeSets = new LinkedList<Collection<AssertionSet>>();
final StringBuilder id = new StringBuilder();
NamespaceVersion mergedVersion = policies.iterator().next().getNamespaceVersion();
for (Policy policy : policies) {
alternativeSets.add(policy.getContent());
if (mergedVersion.compareTo(policy.getNamespaceVersion()) < 0) {
mergedVersion = policy.getNamespaceVersion();
}
final String policyId = policy.getId();
if (policyId != null) {
if (id.length() > 0) {
id.append('-');
}
id.append(policyId);
}
}
final Collection<Collection<AssertionSet>> combinedAlternatives = PolicyUtils.Collections.combine(null, alternativeSets, false);
if (combinedAlternatives == null || combinedAlternatives.isEmpty()) {
return Policy.createNullPolicy(mergedVersion, null, id.length() == 0 ? null : id.toString());
} else {
final Collection<AssertionSet> mergedSetList = new ArrayList<AssertionSet>(combinedAlternatives.size());
for (Collection<AssertionSet> toBeMerged : combinedAlternatives) {
mergedSetList.add(AssertionSet.createMergedAssertionSet(toBeMerged));
}
return Policy.createPolicy(mergedVersion, null, id.length() == 0 ? null : id.toString(), mergedSetList);
}
}
}