org.apache.hadoop.ipc.RemoteException 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.hadoop.ipc;
import java.io.IOException;
import java.lang.reflect.Constructor;
import org.apache.hadoop.ipc.protobuf.RpcHeaderProtos.RpcResponseHeaderProto.RpcErrorCodeProto;
import org.xml.sax.Attributes;
public class RemoteException extends IOException {
/** this value should not be defined in RpcHeader.proto so that protobuf will return a null */
private static final int UNSPECIFIED_ERROR = -1;
/** For java.io.Serializable */
private static final long serialVersionUID = 1L;
private final int errorCode;
private final String className;
/**
* @param className wrapped exception, may be null
* @param msg may be null
*/
public RemoteException(String className, String msg) {
this(className, msg, null);
}
/**
* @param className wrapped exception, may be null
* @param msg may be null
* @param erCode may be null
*/
public RemoteException(String className, String msg, RpcErrorCodeProto erCode) {
super(msg);
this.className = className;
if (erCode != null)
errorCode = erCode.getNumber();
else
errorCode = UNSPECIFIED_ERROR;
}
/**
* @return the class name for the wrapped exception; may be null if none was given.
*/
public String getClassName() {
return className;
}
/**
* @return may be null if the code was newer than our protobuf definitions or none was given.
*/
public RpcErrorCodeProto getErrorCode() {
return RpcErrorCodeProto.valueOf(errorCode);
}
/**
* If this remote exception wraps up one of the lookupTypes
* then return this exception.
*
* Unwraps any IOException.
*
* @param lookupTypes the desired exception class. may be null.
* @return IOException, which is either the lookupClass exception or this.
*/
public IOException unwrapRemoteException(Class... lookupTypes) {
if(lookupTypes == null)
return this;
for(Class lookupClass : lookupTypes) {
if(!lookupClass.getName().equals(getClassName()))
continue;
try {
return instantiateException(lookupClass.asSubclass(IOException.class));
} catch(Exception e) {
// cannot instantiate lookupClass, just return this
return this;
}
}
// wrapped up exception is not in lookupTypes, just return this
return this;
}
/**
* Instantiate and return the exception wrapped up by this remote exception.
*
*
This unwraps any Throwable that has a constructor taking
* a String as a parameter.
* Otherwise it returns this.
*
* @return Throwable
*/
public IOException unwrapRemoteException() {
try {
Class realClass = Class.forName(getClassName());
return instantiateException(realClass.asSubclass(IOException.class));
} catch(Exception e) {
// cannot instantiate the original exception, just return this
}
return this;
}
private IOException instantiateException(Class cls)
throws Exception {
Constructor cn = cls.getConstructor(String.class);
cn.setAccessible(true);
IOException ex = cn.newInstance(this.getMessage());
ex.initCause(this);
return ex;
}
/**
* Create RemoteException from attributes
* @param attrs may not be null
*/
public static RemoteException valueOf(Attributes attrs) {
return new RemoteException(attrs.getValue("class"),
attrs.getValue("message"));
}
@Override
public String toString() {
return getClass().getName() + "(" + className + "): " + getMessage();
}
}