/*
* The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
* (the "License"). You may not use this work except in compliance with the License, which is
* available at www.apache.org/licenses/LICENSE-2.0
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied, as more fully set forth in the License.
*
* See the NOTICE file distributed with this work for information regarding copyright ownership.
*/
package alluxio.collections;
import io.netty.util.internal.chmv8.ConcurrentHashMapV8;
import java.util.Collections;
import java.util.Iterator;
import java.util.Set;
import javax.annotation.concurrent.ThreadSafe;
/**
* A class representing a unique index. A unique index is an index
* where each index value only maps to one object.
*
* @param <T> type of objects in this index
*/
@ThreadSafe
public class UniqueFieldIndex<T> implements FieldIndex<T> {
private final IndexDefinition<T> mIndexDefinition;
private final ConcurrentHashMapV8<Object, T> mIndexMap;
/**
* Constructs a new {@link UniqueFieldIndex} instance.
*
* @param indexDefinition definition of index
*/
public UniqueFieldIndex(IndexDefinition<T> indexDefinition) {
mIndexMap = new ConcurrentHashMapV8<>(8, 0.95f, 8);
mIndexDefinition = indexDefinition;
}
@Override
public boolean add(T object) {
Object fieldValue = mIndexDefinition.getFieldValue(object);
T previousObject = mIndexMap.putIfAbsent(fieldValue, object);
if (previousObject != null && previousObject != object) {
return false;
}
return true;
}
@Override
public boolean remove(T object) {
Object fieldValue = mIndexDefinition.getFieldValue(object);
return mIndexMap.remove(fieldValue, object);
}
@Override
public void clear() {
mIndexMap.clear();
}
@Override
public boolean containsField(Object fieldValue) {
return mIndexMap.containsKey(fieldValue);
}
@Override
public boolean containsObject(T object) {
Object fieldValue = mIndexDefinition.getFieldValue(object);
T res = mIndexMap.get(fieldValue);
if (res == null) {
return false;
}
return res == object;
}
@Override
public Set<T> getByField(Object value) {
T res = mIndexMap.get(value);
if (res != null) {
return Collections.singleton(res);
}
return Collections.emptySet();
}
@Override
public T getFirst(Object value) {
return mIndexMap.get(value);
}
@Override
public Iterator<T> iterator() {
return mIndexMap.values().iterator();
}
@Override
public int size() {
return mIndexMap.size();
}
}