com.hazelcast.map.impl.iterator.AbstractMapIterator Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2021, 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.map.impl.iterator;
import com.hazelcast.internal.util.ConstructorFunction;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
/**
* Base class for iterating map entries in the whole cluster.
*
* @param the key type
* @param the value type
*/
public abstract class AbstractMapIterator implements Iterator> {
protected static final int DEFAULT_FETCH_SIZE = 100;
private final int partitionCount;
private Iterator> lastReadIterator;
private final ConstructorFunction>> createPartitionIterator;
private Iterator> it;
private int idx;
public AbstractMapIterator(ConstructorFunction>> createPartitionIterator,
int partitionCount) {
this.createPartitionIterator = createPartitionIterator;
this.partitionCount = partitionCount;
idx = 0;
it = createPartitionIterator.createNew(idx);
}
@Override
public Map.Entry next() {
if (hasNext()) {
if (it != lastReadIterator) {
lastReadIterator = it;
}
return it.next();
}
throw new NoSuchElementException();
}
@Override
public boolean hasNext() {
while (!it.hasNext()) {
if (idx == partitionCount - 1) {
return false;
}
it = createPartitionIterator.createNew(++idx);
}
return true;
}
@Override
public void remove() {
if (lastReadIterator != null) {
lastReadIterator.remove();
} else {
throw new IllegalStateException("Iterator.next() must be called before remove()!");
}
}
}