org.apache.hadoop.hbase.errorhandling

Class ForeignException

java.lang.Object

java.lang.Throwable

java.lang.Exception

java.io.IOException

org.apache.hadoop.hbase.errorhandling.ForeignException

All Implemented Interfaces:

Serializable

@InterfaceAudience.Public
public class ForeignException
extends IOException

A ForeignException is an exception from another thread or process.

ForeignExceptions are sent to 'remote' peers to signal an abort in the face of failures. When serialized for transmission we encode using Protobufs to ensure version compatibility.

Foreign exceptions contain a Throwable as its cause. This can be a "regular" exception generated locally or a ProxyThrowable that is a representation of the original exception created on original 'remote' source. These ProxyThrowables have their their stacks traces and messages overridden to reflect the original 'remote' exception. The only way these ProxyThrowables are generated are by this class's deserialize(byte[]) method.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	ForeignException.ProxyThrowable This is a Proxy Throwable that contains the information of the original remote exception

Field Summary

Fields

Modifier and Type	Field and Description
private String	source Name of the throwable's source such as a host or thread name.

Constructor Summary

Constructors

Constructor and Description
ForeignException(String source, String msg) Create a new ForeignException that can be serialized.
ForeignException(String source, Throwable cause) Create a new ForeignException that can be serialized.

Method Summary

Modifier and Type	Method and Description
static ForeignException	deserialize(byte[] bytes) Takes a series of bytes and tries to generate an ForeignException instance for it.
String	getSource()
boolean	isRemote() The cause of a ForeignException can be an exception that was generated on a local in process thread, or a thread from a 'remote' separate process.
static byte[]	serialize(String source, Throwable t) Converts a ForeignException to an array of bytes.
private static StackTraceElement[]	toStackTrace(List<org.apache.hadoop.hbase.shaded.protobuf.generated.ErrorHandlingProtos.StackTraceElementMessage> traceList) Unwind a serialized array of ErrorHandlingProtos.StackTraceElementMessages to a StackTraceElements.
private static List<org.apache.hadoop.hbase.shaded.protobuf.generated.ErrorHandlingProtos.StackTraceElementMessage>	toStackTraceElementMessages(StackTraceElement[] trace) Convert a stack trace to list of StackTraceElement.
String	toString()

Methods inherited from class java.lang.Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

source

private final String source

Name of the throwable's source such as a host or thread name. Must be non-null.

Constructor Detail

ForeignException

public ForeignException(String source,
                        Throwable cause)

Create a new ForeignException that can be serialized. It is assumed that this came form a local source. nn

ForeignException

public ForeignException(String source,
                        String msg)

Create a new ForeignException that can be serialized. It is assumed that this is locally generated. nn

Method Detail

getSource

public String getSource()

isRemote

public boolean isRemote()

The cause of a ForeignException can be an exception that was generated on a local in process thread, or a thread from a 'remote' separate process. If the cause is a ProxyThrowable, we know it came from deserialization which usually means it came from not only another thread, but also from a remote thread.

Returns:

true if went through deserialization, false if locally generated

toString

public String toString()

Overrides:

toString in class Throwable

toStackTraceElementMessages

private static List<org.apache.hadoop.hbase.shaded.protobuf.generated.ErrorHandlingProtos.StackTraceElementMessage> toStackTraceElementMessages(StackTraceElement[] trace)

Convert a stack trace to list of StackTraceElement.

Parameters:

trace - the stack trace to convert to protobuf message

Returns:

null if the passed stack is null.

serialize

public static byte[] serialize(String source,
                               Throwable t)

Converts a ForeignException to an array of bytes.

Parameters:

source - the name of the external exception source

t - the "local" external exception (local)

Returns:

protobuf serialized version of ForeignException

deserialize

public static ForeignException deserialize(byte[] bytes)
                                    throws IOException

Takes a series of bytes and tries to generate an ForeignException instance for it. n * @return the ForeignExcpetion instance

Throws:

InvalidProtocolBufferException - if there was deserialization problem this is thrown.

IOException

toStackTrace

private static StackTraceElement[] toStackTrace(List<org.apache.hadoop.hbase.shaded.protobuf.generated.ErrorHandlingProtos.StackTraceElementMessage> traceList)

Unwind a serialized array of ErrorHandlingProtos.StackTraceElementMessages to a StackTraceElements.

Parameters:

traceList - list that was serialized

Returns:

the deserialized list or null if it couldn't be unwound (e.g. wasn't set on the sender).