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package com.sun.xml.ws.policy.sourcemodel;

import com.sun.xml.ws.policy.AssertionSet;
import com.sun.xml.ws.policy.NestedPolicy;
import com.sun.xml.ws.policy.Policy;
import com.sun.xml.ws.policy.PolicyAssertion;
import com.sun.xml.ws.policy.PolicyException;
import com.sun.xml.ws.policy.privateutil.LocalizationMessages;
import com.sun.xml.ws.policy.privateutil.PolicyLogger;
import java.util.Iterator;

/**
 *
 * @author Marek Potociar
 */
public final class PolicyModelGenerator {
    private static final PolicyLogger LOGGER = PolicyLogger.getLogger(PolicyModelTranslator.class);
    private static final PolicyModelGenerator generator = new PolicyModelGenerator();
    
    /**
     * This private constructor avoids direct instantiation from outside of the class
     */
    private PolicyModelGenerator() {
        // nothing to initialize
    }
    
    /**
     * Factory method that returns {@link PolicyModelGenerator} instance.
     *
     * @return {@link PolicyModelGenerator} instance
     */
    public static PolicyModelGenerator getGenerator() {
        return generator;
    }
    
    /**
     * This method translates a {@link Policy} into a
     * {@link com.sun.xml.ws.policy.sourcemodel policy infoset}. The resulting
     * PolicySourceModel is disconnected from the input policy, thus any
     * additional changes in the policy will have no effect on the PolicySourceModel.
     *
     * @param policy The policy to be translated into an infoset. May be null.
     * @return translated The policy infoset. May be null if the input policy was
     * null.
     * @throws PolicyException in case Policy translation fails.
     */
    public PolicySourceModel translate(final Policy policy) throws PolicyException {
        LOGGER.entering(policy);
        
        PolicySourceModel model = null;
        
        if (policy == null) {
            LOGGER.fine(LocalizationMessages.WSP_0047_POLICY_IS_NULL_RETURNING());
        } else {
            model = PolicySourceModel.createPolicySourceModel(policy.getId(), policy.getName());
            
            final ModelNode rootNode = model.getRootNode();
            final ModelNode exactlyOneNode = rootNode.createChildExactlyOneNode();
            for (AssertionSet set : policy) {
                final ModelNode alternativeNode = exactlyOneNode.createChildAllNode();
                for (PolicyAssertion assertion : set) {
                    final AssertionData data = AssertionData.createAssertionData(assertion.getName(), assertion.getValue(), assertion.getAttributes());
                    final ModelNode assertionNode = alternativeNode.createChildAssertionNode(data);
                    if (assertion.hasNestedPolicy()) {
                        translate(assertionNode, assertion.getNestedPolicy());
                    }
                    if (assertion.hasNestedAssertions()) {
                        translate(assertion.getNestedAssertionsIterator(), assertionNode);
                    }
                }
            }
        }
        
        LOGGER.exiting(model);
        return model;
    }
    
    /**
     * Iterates through a nested policy and return the corresponding policy info model.
     *
     * @param policy The nested policy
     * @return The nested policy translated to the policy info model
     */
    private ModelNode translate(final ModelNode parentAssertion, final NestedPolicy policy) {
        final ModelNode nestedPolicyRoot = parentAssertion.createChildPolicyNode();
        final ModelNode exactlyOneNode = nestedPolicyRoot.createChildExactlyOneNode();
        final AssertionSet set = policy.getAssertionSet();
        final ModelNode alternativeNode = exactlyOneNode.createChildAllNode();
        for (PolicyAssertion assertion : set) {
            final AssertionData data = AssertionData.createAssertionData(assertion.getName(), assertion.getValue(), assertion.getAttributes());
            final ModelNode assertionNode = alternativeNode.createChildAssertionNode(data);
            if (assertion.hasNestedPolicy()) {
                translate(assertionNode, assertion.getNestedPolicy());
            }
            if (assertion.hasNestedAssertions()) {
                translate(assertion.getNestedAssertionsIterator(), assertionNode);
            }
        }
        return nestedPolicyRoot;
    }
    
    /**
     * Iterates through all contained assertions and adds them to the info model.
     *
     * @param assertions The set of contained assertions
     * @param assertionNode The node to which the assertions are added as child nodes
     */
    private void translate(final Iterator<PolicyAssertion> assertionParametersIterator, final ModelNode assertionNode) {
        while (assertionParametersIterator.hasNext()) {
            final PolicyAssertion assertionParameter = assertionParametersIterator.next();
            final AssertionData data = AssertionData.createAssertionParameterData(assertionParameter.getName(), assertionParameter.getValue(), assertionParameter.getAttributes());
            final ModelNode assertionParameterNode = assertionNode.createChildAssertionParameterNode(data);
            if (assertionParameter.hasNestedPolicy()) {
                throw LOGGER.logSevereException(new IllegalStateException(LocalizationMessages.WSP_0005_UNEXPECTED_POLICY_ELEMENT_FOUND_IN_ASSERTION_PARAM(assertionParameter)));
            }
            if (assertionParameter.hasNestedAssertions()) {
                translate(assertionParameter.getNestedAssertionsIterator(), assertionParameterNode);
            }
        }
    }
}