/**
* 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.hadoop.hive.ql.exec;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
/**
* ExprNodeEvaluator.
*
*/
public abstract class ExprNodeEvaluator {
/**
* Initialize should be called once and only once. Return the ObjectInspector
* for the return value, given the rowInspector.
*/
public abstract ObjectInspector initialize(ObjectInspector rowInspector) throws HiveException;
/**
* Evaluate the expression given the row. This method should use the
* rowInspector passed in from initialize to inspect the row object. The
* return value will be inspected by the return value of initialize.
*/
public abstract Object evaluate(Object row) throws HiveException;
/**
* Return whether this node (and all children nodes) are deterministic.
*/
public boolean isDeterministic() {
return true;
}
}