/*
 * Copyright 2010 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.base.extractors;

import java.io.Externalizable;

import org.drools.core.base.ValueType;
import org.drools.core.common.ReteEvaluator;

/**
 * A special field extractor for the self reference "this".
 */
public class SelfReferenceClassFieldReader extends BaseObjectClassFieldReader implements Externalizable  {

    private static final long serialVersionUID = 510l;
    
    public SelfReferenceClassFieldReader() {
        
    }

    public SelfReferenceClassFieldReader(final Class<?> clazz) {
        super( 0, // index
               clazz, // fieldType
               ValueType.determineValueType( clazz ) ); // value type
    }

    public Object getValue(ReteEvaluator reteEvaluator, final Object object) {
        return object;
    }
    
    public boolean isNullValue(ReteEvaluator reteEvaluator, final Object object) {
        return getValue( reteEvaluator, object ) == null;
    }
    
    @Override
    public boolean isSelfReference() {
        return true;
    }
}
