org.apache.activemq.artemis.utils.collections.ArrayResettableIterator Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.activemq.artemis.utils.collections;
import java.util.Collection;
/**
* Provides an Array Iterator that is able to reset, allowing you to iterate over the full array.
* It achieves this though by moving end position mark to the the current cursors position,
* so it round robins, even with reset.
* @param
*/
public class ArrayResettableIterator implements ResettableIterator {
private final Object[] array;
private int cursor = 0;
private int endPos = -1;
private boolean hasNext;
public ArrayResettableIterator(Object[] array) {
this.array = array;
reset();
}
public static ResettableIterator iterator(Collection collection) {
return new ArrayResettableIterator<>(collection.toArray());
}
@Override
public void reset() {
endPos = cursor;
hasNext = array.length > 0;
}
@Override
public boolean hasNext() {
return hasNext;
}
@Override
public T next() {
if (!hasNext) {
throw new IllegalStateException();
}
@SuppressWarnings("unchecked") T result = (T) array[cursor];
cursor++;
if (cursor == array.length) {
cursor = 0;
}
if (cursor == endPos) {
hasNext = false;
}
return result;
}
}