/*
* Licensed to Crate under one or more contributor license agreements.
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership. Crate 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.
*
* However, if you have executed another commercial license agreement
* with Crate these terms will supersede the license and you may use the
* software solely pursuant to the terms of the relevant commercial
* agreement.
*/
package io.crate.data;
import io.crate.concurrent.CompletableFutures;
import java.util.concurrent.CompletionStage;
public class LimitingBatchIterator extends CloseAssertingBatchIterator {
private final int endPos;
private int pos = -1;
public static BatchIterator newInstance(BatchIterator delegate, int limit) {
return new LimitingBatchIterator(delegate, limit);
}
private LimitingBatchIterator(BatchIterator delegate, int limit) {
super(delegate);
this.endPos = limit - 1;
}
@Override
public void moveToStart() {
pos = -1;
super.moveToStart();
}
@Override
public boolean moveNext() {
if (pos >= endPos) {
return false;
}
if (super.moveNext()) {
pos++;
return true;
}
return false;
}
@Override
public CompletionStage<?> loadNextBatch() {
if (allLoaded()) {
return CompletableFutures.failedFuture(new IllegalStateException("Iterator already fully loaded"));
}
return super.loadNextBatch();
}
@Override
public boolean allLoaded() {
return pos >= endPos || super.allLoaded();
}
}