/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed 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 eu.stratosphere.api.java.typeutils.runtime.record;
import eu.stratosphere.api.common.typeutils.TypePairComparator;
import eu.stratosphere.types.Key;
import eu.stratosphere.types.NullKeyFieldException;
import eu.stratosphere.types.Record;
import eu.stratosphere.util.InstantiationUtil;
/**
* Implementation of the {@link TypePairComparator} interface for Pact Records. The equality is established on a set of
* key fields. The indices of the key fields may be different on the reference and candidate side.
*/
public class RecordPairComparator extends TypePairComparator<Record, Record> {
private final int[] keyFields1, keyFields2; // arrays with the positions of the keys in the records
@SuppressWarnings("rawtypes")
private final Key[] keyHolders1, keyHolders2; // arrays with mutable objects for the key types
public RecordPairComparator(int[] keyFieldsReference, int[] keyFieldsCandidate, Class<? extends Key<?>>[] keyTypes) {
if (keyFieldsReference.length != keyFieldsCandidate.length || keyFieldsCandidate.length != keyTypes.length) {
throw new IllegalArgumentException(
"The arrays describing the key positions and types must be of the same length.");
}
this.keyFields1 = keyFieldsReference;
this.keyFields2 = keyFieldsCandidate;
// instantiate fields to extract keys into
this.keyHolders1 = new Key[keyTypes.length];
this.keyHolders2 = new Key[keyTypes.length];
for (int i = 0; i < keyTypes.length; i++) {
if (keyTypes[i] == null) {
throw new NullPointerException("Key type " + i + " is null.");
}
this.keyHolders1[i] = InstantiationUtil.instantiate(keyTypes[i], Key.class);
this.keyHolders2[i] = InstantiationUtil.instantiate(keyTypes[i], Key.class);
}
}
// --------------------------------------------------------------------------------------------
@Override
public void setReference(Record reference) {
for (int i = 0; i < this.keyFields1.length; i++) {
if (!reference.getFieldInto(this.keyFields1[i], this.keyHolders1[i])) {
throw new NullKeyFieldException(this.keyFields1[i]);
}
}
}
@SuppressWarnings("rawtypes")
@Override
public boolean equalToReference(Record candidate) {
for (int i = 0; i < this.keyFields2.length; i++) {
final Key k = candidate.getField(this.keyFields2[i], this.keyHolders2[i]);
if (k == null) {
throw new NullKeyFieldException(this.keyFields2[i]);
} else if (!k.equals(this.keyHolders1[i])) {
return false;
}
}
return true;
}
@SuppressWarnings({ "rawtypes", "unchecked" })
@Override
public int compareToReference(Record candidate) {
for (int i = 0; i < this.keyFields2.length; i++) {
final Key k = candidate.getField(this.keyFields2[i], this.keyHolders2[i]);
if (k == null) {
throw new NullKeyFieldException(this.keyFields2[i]);
} else {
final int comp = k.compareTo(this.keyHolders1[i]);
if (comp != 0) {
return comp;
}
}
}
return 0;
}
}