com.datatorrent.lib.streamquery.SelectOperator Maven / Gradle / Ivy
/**
* 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 com.datatorrent.lib.streamquery;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import com.datatorrent.api.DefaultInputPort;
import com.datatorrent.api.DefaultOutputPort;
import com.datatorrent.common.util.BaseOperator;
import com.datatorrent.lib.streamquery.condition.Condition;
import com.datatorrent.lib.streamquery.index.Index;
/**
* An implementation of that provides sql select query semantics on live data stream.
*
* Stream rows passing condition are emitted on output port stream.
*
* StateFull : NO, all row data is processed in current time window.
* Partitions : Yes, No Input dependency among input rows.
*
* Ports:
* inport : Input hash map(row) port, expects
* HashMap<String,Object><
* outport : Output hash map(row) port, emits
* HashMap<String,Object>
*
* Properties :
* condition : Select condition for selecting rows.
* columns : Column names/aggregate functions for select.
*
* @displayName Select
* @category Stream Manipulators
* @tags sql select operator, index, sql condition
* @since 0.3.3
*/
public class SelectOperator extends BaseOperator
{
/**
* select columns/expression;
*/
private ArrayList indexes = new ArrayList();
/**
* condition.
*/
private Condition condition = null;
/**
* add index.
*/
public void addIndex(Index index)
{
indexes.add(index);
}
/**
* set condition.
*/
public void setCondition(Condition condition)
{
this.condition = condition;
}
/**
* Input port that takes a map of <string,object>.
*/
public final transient DefaultInputPort> inport = new DefaultInputPort>()
{
@Override
public void process(Map tuple)
{
if ((condition != null) && (!condition.isValidRow(tuple))) {
return;
}
if (indexes.size() == 0) {
outport.emit(tuple);
return;
}
Map result = new HashMap();
for (int i = 0; i < indexes.size(); i++) {
indexes.get(i).filter(tuple, result);
}
outport.emit(result);
}
};
/**
* Output port that emits a map of <string,object>.
*/
public final transient DefaultOutputPort> outport = new DefaultOutputPort>();
}