org.apache.flink.runtime.jobgraph.tasks.InputSplitIterator Maven / Gradle / Ivy
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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.flink.runtime.jobgraph.tasks;
import java.util.Iterator;
import org.apache.flink.core.io.InputSplit;
/**
* The input split iterator allows a task to iterate over all input splits it is supposed to
* consume. Internally, the input split iterator calls an {@link InputSplitProvider} on each next call in
* order to facilitate lazy split assignment.
*
* @param
*/
public class InputSplitIterator implements Iterator {
/**
* The {@link InputSplitProvider} that is called to provide new input splits.
*/
private final InputSplitProvider inputSplitProvider;
/**
* Buffers the next input split to be returned by this iterator or null it no split is buffered.
*/
private T nextInputSplit = null;
/**
* Constructs a new input split iterator.
*
* @param inputSplitProvider
* the input split provider to be called for new input splits
*/
public InputSplitIterator(final InputSplitProvider inputSplitProvider) {
this.inputSplitProvider = inputSplitProvider;
}
@SuppressWarnings("unchecked")
@Override
public boolean hasNext() {
if (this.nextInputSplit == null) {
this.nextInputSplit = (T) inputSplitProvider.getNextInputSplit();
}
return this.nextInputSplit != null;
}
@SuppressWarnings("unchecked")
@Override
public T next() {
T retVal = null;
if (this.nextInputSplit == null) {
this.nextInputSplit = (T) inputSplitProvider.getNextInputSplit();
}
retVal = this.nextInputSplit;
this.nextInputSplit = null;
return retVal;
}
@Override
public void remove() {
throw new RuntimeException("The InputSplitIterator does not implement the remove method");
}
}