| /** |
| * 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.apex.malhar.sql.operators; |
| |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| import com.datatorrent.api.Context; |
| import com.datatorrent.lib.expression.Expression; |
| import com.datatorrent.lib.transform.TransformOperator; |
| import com.datatorrent.lib.util.PojoUtils; |
| |
| /** |
| * This is an extension of {@link TransformOperator} which also takes care of filtering tuples. |
| * |
| * @since 3.6.0 |
| */ |
| @InterfaceStability.Evolving |
| public class FilterTransformOperator extends TransformOperator |
| { |
| private String condition; |
| private transient Expression conditionExpression; |
| |
| @Override |
| public void activate(Context context) |
| { |
| super.activate(context); |
| if (condition != null) { |
| conditionExpression = PojoUtils.createExpression(inputClass, condition, Boolean.class, |
| expressionFunctions.toArray(new String[expressionFunctions.size()])); |
| } |
| } |
| |
| @Override |
| protected void processTuple(Object in) |
| { |
| if ((conditionExpression != null) && (conditionExpression.execute(in) == Boolean.FALSE)) { |
| return; |
| } |
| |
| super.processTuple(in); |
| } |
| |
| public String getCondition() |
| { |
| return condition; |
| } |
| |
| /** |
| * Set quasi-Java expression which acts as filtering logic for given tuple |
| * |
| * @param condition Expression which can be evaluated for filtering |
| */ |
| public void setCondition(String condition) |
| { |
| this.condition = condition; |
| } |
| } |