/***********************************************************************************************************************
*
* 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;
import java.io.IOException;
import eu.stratosphere.api.common.typeutils.TypeComparator;
import eu.stratosphere.core.memory.DataInputView;
import eu.stratosphere.core.memory.DataOutputView;
import eu.stratosphere.core.memory.MemorySegment;
import eu.stratosphere.types.CopyableValue;
import eu.stratosphere.types.NormalizableKey;
import eu.stratosphere.util.InstantiationUtil;
/**
* Comparator for all Value types that extend Key
*/
public class CopyableValueComparator<T extends CopyableValue<T> & Comparable<T>> extends TypeComparator<T> {
private static final long serialVersionUID = 1L;
private final Class<T> type;
private final boolean ascendingComparison;
private transient T reference;
private transient T tempReference;
public CopyableValueComparator(boolean ascending, Class<T> type) {
this.type = type;
this.ascendingComparison = ascending;
this.reference = InstantiationUtil.instantiate(type, CopyableValue.class);
}
@Override
public int hash(T record) {
return record.hashCode();
}
@Override
public void setReference(T toCompare) {
toCompare.copyTo(reference);
}
@Override
public boolean equalToReference(T candidate) {
return candidate.equals(this.reference);
}
@Override
public int compareToReference(TypeComparator<T> referencedComparator) {
T otherRef = ((CopyableValueComparator<T>) referencedComparator).reference;
int comp = otherRef.compareTo(reference);
return ascendingComparison ? comp : -comp;
}
@Override
public int compare(T first, T second) {
int comp = first.compareTo(second);
return ascendingComparison ? comp : -comp;
}
@Override
public int compare(DataInputView firstSource, DataInputView secondSource) throws IOException {
if (tempReference == null) {
tempReference = InstantiationUtil.instantiate(type, CopyableValue.class);
}
reference.read(firstSource);
tempReference.read(secondSource);
int comp = reference.compareTo(tempReference);
return ascendingComparison ? comp : -comp;
}
@Override
public boolean supportsNormalizedKey() {
return NormalizableKey.class.isAssignableFrom(type);
}
@Override
public int getNormalizeKeyLen() {
NormalizableKey<?> key = (NormalizableKey<?>) reference;
return key.getMaxNormalizedKeyLen();
}
@Override
public boolean isNormalizedKeyPrefixOnly(int keyBytes) {
return keyBytes < getNormalizeKeyLen();
}
@Override
public void putNormalizedKey(T record, MemorySegment target, int offset, int numBytes) {
NormalizableKey<?> key = (NormalizableKey<?>) record;
key.copyNormalizedKey(target, offset, numBytes);
}
@Override
public boolean invertNormalizedKey() {
return !ascendingComparison;
}
@Override
public TypeComparator<T> duplicate() {
return new CopyableValueComparator<T>(ascendingComparison, type);
}
// --------------------------------------------------------------------------------------------
// unsupported normalization
// --------------------------------------------------------------------------------------------
@Override
public boolean supportsSerializationWithKeyNormalization() {
return false;
}
@Override
public void writeWithKeyNormalization(T record, DataOutputView target) throws IOException {
throw new UnsupportedOperationException();
}
@Override
public T readWithKeyDenormalization(T reuse, DataInputView source) throws IOException {
throw new UnsupportedOperationException();
}
// --------------------------------------------------------------------------------------------
// serialization
// --------------------------------------------------------------------------------------------
private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
// read basic object and the type
s.defaultReadObject();
this.reference = InstantiationUtil.instantiate(type, CopyableValue.class);
this.tempReference = null;
}
}