/**
* 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.crunch;
import com.google.common.collect.Iterables;
import org.apache.crunch.fn.Aggregators;
import org.apache.crunch.impl.mr.MRPipeline;
import org.apache.crunch.io.From;
import org.apache.crunch.io.To;
import org.apache.crunch.test.CrunchTestSupport;
import org.apache.crunch.types.writable.Writables;
import org.junit.Test;
import java.io.Serializable;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
public class EmptyPCollectionIT extends CrunchTestSupport implements Serializable {
private static class SplitFn extends DoFn<String, Pair<String, Long>> {
@Override
public void process(String input, Emitter<Pair<String, Long>> emitter) {
for (String word : input.split("\\s+")) {
emitter.emit(Pair.of(word, 1L));
}
}
}
@Test
public void testEmptyMR() throws Exception {
MRPipeline p = new MRPipeline(EmptyPCollectionIT.class, tempDir.getDefaultConfiguration());
assertTrue(Iterables.isEmpty(p.emptyPCollection(Writables.strings())
.parallelDo(new SplitFn(), Writables.tableOf(Writables.strings(), Writables.longs()))
.groupByKey()
.combineValues(Aggregators.SUM_LONGS())
.materialize()));
p.done();
}
@Test
public void testUnionWithEmptyMR() throws Exception {
MRPipeline p = new MRPipeline(EmptyPCollectionIT.class, tempDir.getDefaultConfiguration());
assertFalse(Iterables.isEmpty(p.emptyPCollection(Writables.strings())
.parallelDo(new SplitFn(), Writables.tableOf(Writables.strings(), Writables.longs()))
.union(
p.read(From.textFile(tempDir.copyResourceFileName("shakes.txt")))
.parallelDo(new SplitFn(), Writables.tableOf(Writables.strings(), Writables.longs())))
.groupByKey()
.combineValues(Aggregators.SUM_LONGS())
.materialize()));
p.done();
}
@Test
public void testUnionTableWithEmptyMR() throws Exception {
MRPipeline p = new MRPipeline(EmptyPCollectionIT.class, tempDir.getDefaultConfiguration());
assertFalse(Iterables.isEmpty(p.emptyPTable(Writables.tableOf(Writables.strings(), Writables.longs()))
.union(
p.read(From.textFile(tempDir.copyResourceFileName("shakes.txt")))
.parallelDo(new SplitFn(), Writables.tableOf(Writables.strings(), Writables.longs())))
.groupByKey()
.combineValues(Aggregators.SUM_LONGS())
.materialize()));
p.done();
}
}