/**
* 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.lib.sort;
import java.util.List;
import com.google.common.collect.Lists;
import org.apache.crunch.lib.Sort.ColumnOrder;
import org.apache.crunch.lib.Sort.Order;
import org.apache.crunch.types.writable.TupleWritable;
import org.apache.crunch.types.writable.WritableType;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;
import com.google.common.base.Joiner;
public class TupleWritableComparator extends WritableComparator implements Configurable {
private static final String CRUNCH_ORDERING_PROPERTY = "crunch.ordering";
private Configuration conf;
private ColumnOrder[] columnOrders;
public TupleWritableComparator() {
super(TupleWritable.class, true);
}
public static void configureOrdering(Configuration conf, WritableType[] types, ColumnOrder[] columnOrders) {
List<String> ordering = Lists.newArrayList();
for (int i = 0; i < types.length; i++) {
ordering.add(columnOrders[i].order().name());
}
conf.set(CRUNCH_ORDERING_PROPERTY, Joiner.on(",").join(ordering));
}
@Override
public int compare(WritableComparable a, WritableComparable b) {
TupleWritable ta = (TupleWritable) a;
TupleWritable tb = (TupleWritable) b;
for (int index = 0; index < columnOrders.length; index++) {
int order = 1;
if (columnOrders[index].order() == Order.ASCENDING) {
order = 1;
} else if (columnOrders[index].order() == Order.DESCENDING) {
order = -1;
} else { // ignore
continue;
}
if (!ta.has(index) && !tb.has(index)) {
continue;
} else if (ta.has(index) && !tb.has(index)) {
return order;
} else if (!ta.has(index) && tb.has(index)) {
return -order;
} else {
Writable v1 = ta.get(index);
Writable v2 = tb.get(index);
if (v1 != v2 && (v1 != null && !v1.equals(v2))) {
if (v1 instanceof WritableComparable && v2 instanceof WritableComparable) {
int cmp = ((WritableComparable) v1).compareTo((WritableComparable) v2);
if (cmp != 0) {
return order * cmp;
}
} else {
int cmp = v1.hashCode() - v2.hashCode();
if (cmp != 0) {
return order * cmp;
}
}
}
}
}
return 0; // ordering using specified cols found no differences
}
@Override
public Configuration getConf() {
return conf;
}
@Override
public void setConf(Configuration conf) {
this.conf = conf;
if (conf != null) {
String ordering = conf.get(CRUNCH_ORDERING_PROPERTY);
String[] columnOrderNames = ordering.split(",");
columnOrders = new ColumnOrder[columnOrderNames.length];
for (int i = 0; i < columnOrders.length; i++) {
Order order = Order.valueOf(columnOrderNames[i]);
columnOrders[i] = ColumnOrder.by(i + 1, order);
}
}
}
}