/*
 * Copyright 2005 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.drools.core.common;


import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;

import org.drools.core.factmodel.traits.CoreWrapper;
import org.drools.core.factmodel.traits.TraitTypeEnum;
import org.drools.core.util.AbstractHashTable;
import org.drools.core.util.AbstractHashTable.AbstractObjectComparator;

public class IdentityAssertMapComparator
    extends
    AbstractObjectComparator {
    private static final long serialVersionUID = 510l;

    public IdentityAssertMapComparator() {
    }

    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
    }

    public void writeExternal(ObjectOutput out) throws IOException {
    }

    public int hashCodeOf(final Object obj) {
        if (obj instanceof InternalFactHandle) {
            return AbstractHashTable.rehash(((InternalFactHandle)obj).getIdentityHashCode());
        } else {
            return AbstractHashTable.rehash( System.identityHashCode( obj ) );
        }
    }

    /**
     * Special comparator that allows FactHandles to be keys, but always  checks
     * like for like.
     */
    public boolean equal(final Object o1,
                         final Object o2) {
        if ( o1 instanceof InternalFactHandle ) {
            return ((InternalFactHandle) o1).getId() == ((InternalFactHandle) o2).getId();
        }
        Object left = o1;
        final InternalFactHandle handle = ((InternalFactHandle) o2);

        if ( left == handle.getObject() ) {
            return true;
        } else if ( handle.getTraitType() == TraitTypeEnum.WRAPPED_TRAITABLE ) {
            return left == ( (CoreWrapper) handle.getObject() ).getCore();
        } else {
            return false;
        }
    }

    public int compare(final Object o1,
                       final Object o2) {
        return ((Comparable) o1).compareTo( o2 );
    }

    public String toString() {
        return "identity";
    }
}