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* 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.cayenne;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* Defines API of a batch iterator over the ResultIterator returned as a result of
* Select queries execution. Usually a ResultBatchIterator is supported by an open
* java.sql.ResultSet, therefore ResultBatchIterator must be explicitly closed when
* the user is done working with them.
*
* @since 4.0
*/
public class ResultBatchIterator<T> implements Iterable<List<T>>, Iterator<List<T>>, AutoCloseable {
private final ResultIterator<T> delegate;
private final int size;
public ResultBatchIterator(ResultIterator<T> delegate, int size) {
this.delegate = delegate;
this.size = size;
}
@Override
public Iterator<List<T>> iterator() {
return this;
}
@Override
public boolean hasNext() {
return delegate.hasNextRow();
}
@Override
public List<T> next() {
List<T> objects = new ArrayList<>(size);
for (int i = 0; i < size && hasNext(); i++) {
objects.add((T) delegate.nextRow());
}
return objects;
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove not supported.");
}
@Override
public void close() {
delegate.close();
}
public int getBatchSize() {
return size;
}
}