org.apache.flink.runtime.state.PlaceholderStreamStateHandle 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.state;
import org.apache.flink.core.fs.FSDataInputStream;
import org.apache.flink.runtime.state.memory.ByteStreamStateHandle;
import java.util.Optional;
/**
* A placeholder state handle for shared state that will replaced by an original that was created in
* a previous checkpoint. So we don't have to send a state handle twice, e.g. in case of {@link
* ByteStreamStateHandle}. This class is used in the referenced states of {@link
* IncrementalRemoteKeyedStateHandle}.
*/
public class PlaceholderStreamStateHandle implements StreamStateHandle {
private static final long serialVersionUID = 1L;
public PlaceholderStreamStateHandle() {}
@Override
public FSDataInputStream openInputStream() {
throw new UnsupportedOperationException(
"This is only a placeholder to be replaced by a real StreamStateHandle in the checkpoint coordinator.");
}
@Override
public Optional asBytesIfInMemory() {
throw new UnsupportedOperationException(
"This is only a placeholder to be replaced by a real StreamStateHandle in the checkpoint coordinator.");
}
@Override
public void discardState() throws Exception {
// nothing to do.
}
@Override
public long getStateSize() {
return 0L;
}
}