org.apache.flink.runtime.state.ChainedStateHandle Maven / Gradle / Ivy
/*
* 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.util.Preconditions;
import java.util.Collections;
import java.util.List;
/**
* Handle to state handles for the operators in an operator chain.
*/
public class ChainedStateHandle implements StateObject {
private static final long serialVersionUID = 1L;
/** The state handles for all operators in the chain */
private final List operatorStateHandles;
/**
* Wraps a list to the state handles for the operators in a chain. Individual state handles can be null.
*
* @param operatorStateHandles list with the state handles for the states in the operator chain.
*/
public ChainedStateHandle(List operatorStateHandles) {
this.operatorStateHandles = Preconditions.checkNotNull(operatorStateHandles);
}
/**
* Check if there are any states handles present. Notice that this can be true even if {@link #getLength()} is
* greater than zero, because state handles can be null.
*
* @return true if there are no state handles for any operator.
*/
public boolean isEmpty() {
for (T state : operatorStateHandles) {
if (state != null) {
return false;
}
}
return true;
}
/**
* Returns the length of the operator chain. This can be different from the number of operator state handles,
* because the some operators in the chain can have no state and thus their state handle can be null.
*
* @return length of the operator chain
*/
public int getLength() {
return operatorStateHandles.size();
}
/**
* Get the state handle for a single operator in the operator chain by it's index.
*
* @param index the index in the operator chain
* @return state handle to the operator at the given position in the operator chain. can be null.
*/
public T get(int index) {
return operatorStateHandles.get(index);
}
@Override
public void discardState() throws Exception {
StateUtil.bestEffortDiscardAllStateObjects(operatorStateHandles);
}
@Override
public long getStateSize() {
long sumStateSize = 0;
if (operatorStateHandles != null) {
for (T state : operatorStateHandles) {
if (state != null) {
sumStateSize += state.getStateSize();
}
}
}
// State size as sum of all state sizes
return sumStateSize;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
ChainedStateHandle that = (ChainedStateHandle) o;
return operatorStateHandles.equals(that.operatorStateHandles);
}
@Override
public int hashCode() {
return operatorStateHandles.hashCode();
}
public static ChainedStateHandle wrapSingleHandle(T stateHandleToWrap) {
return new ChainedStateHandle(Collections.singletonList(stateHandleToWrap));
}
public static boolean isNullOrEmpty(ChainedStateHandle chainedStateHandle) {
return chainedStateHandle == null || chainedStateHandle.isEmpty();
}
}