/*
 * Copyright Red Hat, Inc. and/or its affiliates
 * and other contributors as indicated by the @author tags and
 * the COPYRIGHT.txt file distributed with this work.
 *
 * 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.teiid.query.sql.lang;

import org.teiid.core.util.EquivalenceUtil;
import org.teiid.core.util.HashCodeUtil;
import org.teiid.query.sql.*;


/**
 * A logical criteria that takes the logical NOT of the contained criteria.  
 * That is, if the contained criteria returns true, this criteria returns 
 * false.  For example:  "NOT (element = 5)"
 */
public class NotCriteria extends AtomicCriteria {

	/**
	 * Constructs a default instance of this class.
	 */
	public NotCriteria() {
	}

	/**
	 * Constructs an instance of this class with sub-criteria.
	 * @param crit Contained criteria
	 */
	public NotCriteria(Criteria crit) {
		super(crit);
	}

    public void acceptVisitor(LanguageVisitor visitor) {
        visitor.visit(this);
    }
	
    
    /**
     * Compare equality of two AtomicCriteria.
     * @param obj Other object
     * @return True if equivalent
     */
    public boolean equals(Object obj) {
        if(obj == this) {
            return true;
        }

        if(!(obj instanceof NotCriteria)) {
            return false;
        }
        
        return EquivalenceUtil.areEqual(getCriteria(), ((NotCriteria)obj).getCriteria());
    }

    /**
     * Get hash code
     * @return Hash code
     */
    public int hashCode() {
        return HashCodeUtil.hashCode(0, getCriteria());
    }
	
	/**
	 * Deep copy of object
	 * @return Deep copy of object
	 */
	public Object clone() {
		return new NotCriteria( (Criteria) getCriteria().clone() );  
	}
	
}
