com.hazelcast.flakeidgen.impl.IdBatch 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.flakeidgen.impl;
import com.hazelcast.flakeidgen.FlakeIdGenerator;
import javax.annotation.Nonnull;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* Set of IDs returned from {@link FlakeIdGenerator}.
*
* IDs can be iterated using a foreach loop:
*
{@code
* IdBatch idBatch = myFlakeIdGenerator.newIdBatch(100);
* for (Long id : idBatch) {
* // ... use the id
* }
* }
*
* Object is immutable.
*/
public class IdBatch implements Iterable {
private final long base;
private final long increment;
private final int batchSize;
/**
* Constructor
*
* @param base See {@link #base()}
* @param increment See {@link #increment()}
* @param batchSize See {@link #batchSize()}
*/
public IdBatch(long base, long increment, int batchSize) {
this.base = base;
this.increment = increment;
this.batchSize = batchSize;
}
/**
* Returns the first ID in the set.
*/
public long base() {
return base;
}
/**
* Returns increment from {@link #base()} for the next ID in the set.
*/
public long increment() {
return increment;
}
/**
* Returns number of IDs in the set.
*/
public int batchSize() {
return batchSize;
}
/**
* Returns iterator that will iterate contained IDs (boxing the as {@code Long}).
* {@code remove()} is not supported.
*/
@Nonnull
public Iterator iterator() {
return new Iterator() {
private long base2 = base;
private int remaining = batchSize;
@Override
public boolean hasNext() {
return remaining > 0;
}
@Override
public Long next() {
if (remaining == 0) {
throw new NoSuchElementException();
}
remaining--;
try {
return base2;
} finally {
base2 += increment;
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
}