/*
* Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.query;
import com.hazelcast.nio.ObjectDataInput;
import com.hazelcast.nio.ObjectDataOutput;
import com.hazelcast.nio.serialization.IdentifiedDataSerializable;
import com.hazelcast.nio.serialization.BinaryInterface;
import com.hazelcast.query.impl.predicates.PredicateDataSerializerHook;
import java.io.IOException;
import java.util.Map;
import static com.hazelcast.util.Preconditions.checkNotNull;
/**
* A {@link Predicate} that restricts the execution of a Predicate to a single Partition.
*
* This can help to speed up query execution since only a single instead of all partitions needs to be queried.
*
* This predicate can only be used as an outer predicate.
*
* @param <K> type of the entry key
* @param <V> type of the entry value
*/
@BinaryInterface
public class PartitionPredicate<K, V> implements Predicate<K, V>, IdentifiedDataSerializable {
private Object partitionKey;
private Predicate<K, V> target;
// should only be used for deserialization
public PartitionPredicate() {
}
/**
* Creates a new PartitionPredicate.
*
* @param partitionKey the partition key
* @param target the target {@link Predicate}
* @throws IllegalArgumentException if partitionId smaller than zero
* @throws NullPointerException if target Predicate is {@code null}
*/
public PartitionPredicate(Object partitionKey, Predicate<K, V> target) {
this.partitionKey = checkNotNull(partitionKey, "partitionKey can't be null");
this.target = checkNotNull(target, "target predicate can't be null");
}
/**
* Returns the partition key that determines the partition the target {@link Predicate} is going to execute on.
*
* @return the partition id
*/
public Object getPartitionKey() {
return partitionKey;
}
/**
* Returns the target {@link Predicate}.
*
* @return the target {@link Predicate}.
*/
public Predicate<K, V> getTarget() {
return target;
}
@Override
public boolean apply(Map.Entry<K, V> mapEntry) {
throw new UnsupportedOperationException();
}
@Override
public int getFactoryId() {
return PredicateDataSerializerHook.F_ID;
}
@Override
public int getId() {
return PredicateDataSerializerHook.PARTITION_PREDICATE;
}
@Override
public void writeData(ObjectDataOutput out) throws IOException {
out.writeObject(partitionKey);
out.writeObject(target);
}
@Override
public void readData(ObjectDataInput in) throws IOException {
this.partitionKey = in.readObject();
this.target = in.readObject();
}
@Override
public String toString() {
return "PartitionPredicate{"
+ "partitionKey=" + partitionKey
+ ", target=" + target
+ '}';
}
}