/*
* 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.pig.backend.hadoop.executionengine.tez.plan.udf;
import java.io.IOException;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.pig.EvalFunc;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.backend.hadoop.executionengine.tez.runtime.ObjectCache;
import org.apache.pig.backend.hadoop.executionengine.tez.runtime.TezInput;
import org.apache.pig.data.Tuple;
import org.apache.tez.runtime.api.LogicalInput;
import org.apache.tez.runtime.library.api.KeyValueReader;
public class ReadScalarsTez extends EvalFunc<Object> implements TezInput {
private static final Log LOG = LogFactory.getLog(ReadScalarsTez.class);
private String inputKey;
private transient Tuple t;
private transient LogicalInput input;
public ReadScalarsTez(String inputKey) {
this.inputKey = inputKey;
}
@Override
public String[] getTezInputs() {
return new String[] { inputKey };
}
@Override
public void replaceInput(String oldInputKey, String newInputKey) {
if (oldInputKey.equals(inputKey)) {
inputKey = newInputKey;
}
}
@Override
public void addInputsToSkip(Set<String> inputsToSkip) {
String cacheKey = "scalar-" + inputKey;
Object cacheValue = ObjectCache.getInstance().retrieve(cacheKey);
if (cacheValue != null) {
inputsToSkip.add(inputKey);
}
}
@Override
public void attachInputs(Map<String, LogicalInput> inputs,
Configuration conf) throws ExecException {
String cacheKey = "scalar-" + inputKey;
Object cacheValue = ObjectCache.getInstance().retrieve(cacheKey);
if (cacheValue != null) {
t = (Tuple) cacheValue;
return;
}
input = inputs.get(inputKey);
if (input == null) {
throw new ExecException("Input from vertex " + inputKey + " is missing");
}
try {
KeyValueReader reader = (KeyValueReader) input.getReader();
if (reader.next()) {
t = (Tuple) reader.getCurrentValue();
String first = t == null ? null : t.toString();
if (reader.next()) {
String msg = "Scalar has more than one row in the output. "
+ "1st : " + first + ", 2nd :"
+ reader.getCurrentValue();
throw new ExecException(msg);
}
} else {
LOG.info("Scalar input from vertex " + inputKey + " is null");
}
LOG.info("Attached input from vertex " + inputKey + " : input=" + input + ", reader=" + reader);
} catch (Exception e) {
throw new ExecException(e);
}
ObjectCache.getInstance().cache(cacheKey, t);
log.info("Cached scalar in Tez ObjectRegistry with vertex scope. cachekey=" + cacheKey);
}
@Override
public Object exec(Tuple input) throws IOException {
int pos = (Integer) input.get(0);
Object obj = t.get(pos);
return obj;
}
}