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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

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 * You should have received a copy of the GNU General Public License version

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

import java.util.Collection;

import java.util.Collections;

import java.util.Comparator;

import java.util.Iterator;

import java.util.Set;

import java.util.TreeSet;

import javax.xml.namespace.QName;

import com.sun.xml.internal.ws.policy.privateutil.LocalizationMessages;

import com.sun.xml.internal.ws.policy.privateutil.PolicyUtils;

import java.util.LinkedList;

import java.util.List;

/**

 * The AssertionSet is a set of assertions. It represents a single policy alternative.

 *

 * @author Fabian Ritzmann, Marek Potociar

 */

public final class AssertionSet implements Iterable<PolicyAssertion>, Comparable<AssertionSet> {

    private static final AssertionSet EMPTY_ASSERTION_SET = new AssertionSet(Collections.unmodifiableList(new LinkedList<PolicyAssertion>()));

    /**

     * The comparator comapres policy assertions according to their publicly accessible attributes, in the following

     * order of attributes:

     *

     * 1. namespace (not null String)

     * 2. local name (not null String)

     * 3. value (String): null < "" < "not empty"

     * 4. has nested assertions (boolean): false < true

     * 5. has nested policy (boolean): false < true

     * 6. hashCode comparison

     */

    private static final Comparator<PolicyAssertion> ASSERTION_COMPARATOR = new Comparator<PolicyAssertion>() {

        public int compare(final PolicyAssertion pa1, final PolicyAssertion pa2) {

            if (pa1.equals(pa2)) {

                return 0;

            }

            int result;

            result = PolicyUtils.Comparison.QNAME_COMPARATOR.compare(pa1.getName(), pa2.getName());

            if (result != 0) {

                return result;

            }

            result = PolicyUtils.Comparison.compareNullableStrings(pa1.getValue(), pa2.getValue());

            if (result != 0) {

                return result;

            }

            result = PolicyUtils.Comparison.compareBoolean(pa1.hasNestedAssertions(), pa2.hasNestedAssertions());

            if (result != 0) {

                return result;

            }

            result = PolicyUtils.Comparison.compareBoolean(pa1.hasNestedPolicy(), pa2.hasNestedPolicy());

            if (result != 0) {

                return result;

            }

            return Math.round(Math.signum(pa1.hashCode() - pa2.hashCode()));

        }

    };

    private final List<PolicyAssertion> assertions;

    private final Set<QName> vocabulary = new TreeSet<QName>(PolicyUtils.Comparison.QNAME_COMPARATOR);

    private final Collection<QName> immutableVocabulary = Collections.unmodifiableCollection(vocabulary);

    private AssertionSet(List<PolicyAssertion> list) {

        assert (list != null) : LocalizationMessages.WSP_0037_PRIVATE_CONSTRUCTOR_DOES_NOT_TAKE_NULL();

        this.assertions = list;

    }

    private AssertionSet(final Collection<AssertionSet> alternatives) {

        this.assertions = new LinkedList<PolicyAssertion>();

        for (AssertionSet alternative : alternatives) {

            addAll(alternative.assertions);

        }

    }

    private boolean add(final PolicyAssertion assertion) {

        if (assertion == null) {

            return false;

        }

        if (this.assertions.contains(assertion)) {

            return false;

        } else {

            this.assertions.add(assertion);

            this.vocabulary.add(assertion.getName());

            return true;

        }

    }

    private boolean addAll(final Collection<? extends PolicyAssertion> assertions) {

        boolean result = true;

        if (assertions != null) {

            for (PolicyAssertion assertion : assertions) {

                result &= add(assertion); // this is here to ensure that vocabulary is built correctly as well

            }

        }

        return result;

    }

    /**

     * Return all assertions contained in this assertion set.

     *

     * @return All assertions contained in this assertion set

     */

    Collection<PolicyAssertion> getAssertions() {

        return assertions;

    }

    /**

     * Retrieves the vocabulary of this policy expression. The vocabulary is represented by an immutable collection of

     * unique QName objects. Each of those objects represents single assertion type contained in the assertion set.

     *

     * @return immutable collection of assertion types contained in the assertion set (a policy vocabulary).

     */

    Collection<QName> getVocabulary() {

        return immutableVocabulary;

    }

    /**

     * Checks whether this policy alternative is compatible with the provided policy alternative.

     *

     * @param alternative policy alternative used for compatibility test

     * @param mode compatibility mode to be used

     * @return {@code true} if the two policy alternatives are compatible, {@code false} otherwise

     */

    boolean isCompatibleWith(final AssertionSet alternative, PolicyIntersector.CompatibilityMode mode) {

        boolean result = (mode == PolicyIntersector.CompatibilityMode.LAX) || this.vocabulary.equals(alternative.vocabulary);

        result = result && this.areAssertionsCompatible(alternative, mode);

        result = result && alternative.areAssertionsCompatible(this, mode);

        return result;

    }

    private boolean areAssertionsCompatible(final AssertionSet alternative, PolicyIntersector.CompatibilityMode mode) {

        nextAssertion: for (PolicyAssertion thisAssertion : this.assertions) {

            if ((mode == PolicyIntersector.CompatibilityMode.STRICT) || !thisAssertion.isIgnorable()) {

                for (PolicyAssertion thatAssertion : alternative.assertions) {

                    if (thisAssertion.isCompatibleWith(thatAssertion, mode)) {

                        continue nextAssertion;

                    }

                }

                return false;

            }

        }

        return true;

    }

    /**

     * Creates and returns new assertion set holding content of all provided policy assertion sets.

     * <p/>

     * This method should not be used to perform a merge of general Policy instances. A client should be aware of the

     * method's result meaning and the difference between merge of Policy instances and merge of AssertionSet instances.

     *

     *

     * @param alternatives collection of provided policy assertion sets which content is to be stored in the assertion set.

     *        May be {@code null} - empty assertion set is returned in such case.

     * @return new instance of assertion set holding the content of all provided policy assertion sets.

     */

    public static AssertionSet createMergedAssertionSet(final Collection<AssertionSet> alternatives) {

        if (alternatives == null || alternatives.isEmpty()) {

            return EMPTY_ASSERTION_SET;

        }

        final AssertionSet result = new AssertionSet(alternatives);

        Collections.sort(result.assertions, ASSERTION_COMPARATOR);

        return result;

    }

    /**

     * Creates and returns new assertion set holding a set of provided policy assertions.

     *

     * @param assertions collection of provided policy assertions to be stored in the assertion set. May be {@code null}.

     * @return new instance of assertion set holding the provided policy assertions

     */

    public static AssertionSet createAssertionSet(final Collection<? extends PolicyAssertion> assertions) {

        if (assertions == null || assertions.isEmpty()) {

            return EMPTY_ASSERTION_SET;

        }

        final AssertionSet result = new AssertionSet(new LinkedList<PolicyAssertion>());

        result.addAll(assertions);

        Collections.sort(result.assertions, ASSERTION_COMPARATOR);

        return result;

    }

    public static AssertionSet emptyAssertionSet() {

        return EMPTY_ASSERTION_SET;

    }

    /**

     * Returns an iterator over a set of child policy assertion objects.

     *

     * @return policy assertion Iterator.

     */

    public Iterator<PolicyAssertion> iterator() {

        return this.assertions.iterator();

    }

    /**

     * Searches for assertions with given name. Only assertions that are contained as immediate children of the assertion set are

     * searched, i.e. nested policies are not searched.

     *

     * @param name The fully qualified name of searched assertion

     * @return List of all assertions matching the requested name. If no assertions are found, the returned list is empty

     * (i.e. {@code null} value is never returned).

     */

    public Collection<PolicyAssertion> get(final QName name) {

        final List<PolicyAssertion> matched = new LinkedList<PolicyAssertion>();

        if (vocabulary.contains(name)) {

            // we iterate the assertion set only if we are sure we contain such assertion name in our vocabulary

            for (PolicyAssertion assertion : assertions) {

                if (assertion.getName().equals(name)) {

                    matched.add(assertion);

                }

            }

        }

        return matched;

    }

    /**

     * Returns {@code true} if this assertion set contains no assertions.

     *

     * @return {@code true} if this assertion set contains no assertions.

     */

    public boolean isEmpty() {

        return assertions.isEmpty();

    }

    /**

     * Returns true if the assertion set contains the assertion name specified in its vocabulary

     *

     * @param assertionName the fully qualified name of the assertion

     * @return {@code true}, if an assertion with the given name could be found in the assertion set vocabulary {@code false} otherwise.

     */

    public boolean contains(final QName assertionName) {

        return vocabulary.contains(assertionName);

    }

    /**

     * An {@code Comparable<T>.compareTo(T o)} interface method implementation.

     * @param that other alternative to compare with

     */

    public int compareTo(final AssertionSet that) {

        if (this.equals(that)) {

            return 0;

        }

        // comparing vocabularies

        final Iterator<QName> vIterator1 = this.getVocabulary().iterator();

        final Iterator<QName> vIterator2 = that.getVocabulary().iterator();

        while (vIterator1.hasNext()) {

            final QName entry1 = vIterator1.next();

            if (vIterator2.hasNext()) {

                final QName entry2 = vIterator2.next();

                final int result = PolicyUtils.Comparison.QNAME_COMPARATOR.compare(entry1, entry2);

                if (result != 0) {

                    return result;

                }

            } else {

                return 1; // we have more entries in this vocabulary

            }

        }

        if (vIterator2.hasNext()) {

            return -1;  // we have more entries in that vocabulary

        }

        // vocabularies are equal => comparing assertions

        final Iterator<PolicyAssertion> pIterator1 = this.getAssertions().iterator();

        final Iterator<PolicyAssertion> pIterator2 = that.getAssertions().iterator();

        while (pIterator1.hasNext()) {

            final PolicyAssertion pa1 = pIterator1.next();

            if (pIterator2.hasNext()) {

                final PolicyAssertion pa2 = pIterator2.next();

                final int result = ASSERTION_COMPARATOR.compare(pa1, pa2);

                if (result != 0) {

                    return result;

                }

            } else {

                return 1; // we have more entries in this assertion set

            }

        }

        if (pIterator2.hasNext()) {

            return -1;  // we have more entries in that assertion set

        }

        // seems like objects are very simmilar although not equal => we must not return 0 otherwise the TreeSet

        // holding this element would discard the newly added element. Thus we return that the first argument is

        // greater than second (just because it is first...)

        return 1;

    }

    /**

     * An {@code Object.equals(Object obj)} method override.

     */

    public boolean equals(final Object obj) {

        if (this == obj) {

            return true;

        }

        if (!(obj instanceof AssertionSet)) {

            return false;

        }

        final AssertionSet that = (AssertionSet) obj;

        boolean result = true;

        result = result && this.vocabulary.equals(that.vocabulary);

        result = result && this.assertions.size() == that.assertions.size() && this.assertions.containsAll(that.assertions);

        return result;

    }

    /**

     * An {@code Object.hashCode()} method override.

     */

    public int hashCode() {

        int result = 17;

        result = 37 * result + vocabulary.hashCode();

        result = 37 * result + assertions.hashCode();

        return result;

    }

    /**

     * An {@code Object.toString()} method override.

     */

    public String toString() {

        return toString(0, new StringBuffer()).toString();

    }

    /**

     * A helper method that appends indented string representation of this instance to the input string buffer.

     *

     * @param indentLevel indentation level to be used.

     * @param buffer buffer to be used for appending string representation of this instance

     * @return modified buffer containing new string representation of the instance

     */

    StringBuffer toString(final int indentLevel, final StringBuffer buffer) {

        final String indent = PolicyUtils.Text.createIndent(indentLevel);

        final String innerIndent = PolicyUtils.Text.createIndent(indentLevel + 1);

        buffer.append(indent).append("assertion set {").append(PolicyUtils.Text.NEW_LINE);

        if (assertions.isEmpty()) {

            buffer.append(innerIndent).append("no assertions").append(PolicyUtils.Text.NEW_LINE);

        } else {

            for (PolicyAssertion assertion : assertions) {

                assertion.toString(indentLevel + 1, buffer).append(PolicyUtils.Text.NEW_LINE);

            }

        }

        buffer.append(indent).append('}');

        return buffer;

    }

}