0.10/xmlps/src/main/java/org/apache/oodt/xmlps/queryparser/Expression.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.oodt.xmlps.queryparser;

/**
 * 
 * The abstract interface for our expression tree.
 */
public interface Expression {

    /**
     * Defines how to turn this Expression into a String-readable query to an
     * underlying SQL database.
     * 
     * @return A String-readable version of this Expression.
     */
    public String evaluate();

}