org.apache.flink.util.SerializedValue 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.util;
import org.apache.flink.annotation.Internal;
import java.io.IOException;
import java.util.Arrays;
/**
* This class is used to transfer (via serialization) objects whose classes are not available
* in the system class loader. When those objects are deserialized without access to their
* special class loader, the deserialization fails with a {@code ClassNotFoundException}.
*
* To work around that issue, the SerializedValue serialized data immediately into a byte array.
* When send through RPC or another service that uses serialization, only the byte array is
* transferred. The object is deserialized later (upon access) and requires the accessor to
* provide the corresponding class loader.
*
* @param The type of the value held.
*/
@Internal
public class SerializedValue implements java.io.Serializable {
private static final long serialVersionUID = -3564011643393683761L;
/** The serialized data. */
private final byte[] serializedData;
private SerializedValue(byte[] serializedData) {
Preconditions.checkNotNull(serializedData, "Serialized data");
this.serializedData = serializedData;
}
public SerializedValue(T value) throws IOException {
this.serializedData = value == null ? null : InstantiationUtil.serializeObject(value);
}
@SuppressWarnings("unchecked")
public T deserializeValue(ClassLoader loader) throws IOException, ClassNotFoundException {
Preconditions.checkNotNull(loader, "No classloader has been passed");
return serializedData == null ? null : (T) InstantiationUtil.deserializeObject(serializedData, loader);
}
/**
* Returns the serialized value or null if no value is set.
*
* @return Serialized data.
*/
public byte[] getByteArray() {
return serializedData;
}
public static SerializedValue fromBytes(byte[] serializedData) {
return new SerializedValue<>(serializedData);
}
// --------------------------------------------------------------------------------------------
@Override
public int hashCode() {
return serializedData == null ? 0 : Arrays.hashCode(serializedData);
}
@Override
public boolean equals(Object obj) {
if (obj instanceof SerializedValue) {
SerializedValue other = (SerializedValue) obj;
return this.serializedData == null ? other.serializedData == null :
(other.serializedData != null && Arrays.equals(this.serializedData, other.serializedData));
}
else {
return false;
}
}
@Override
public String toString() {
return "SerializedValue";
}
}