ForeignException (Apache HBase 1.2.12 API)

java.lang.Object
- java.lang.Throwable
- - java.lang.Exception
  - - java.io.IOException
    - - org.apache.hadoop.hbase.errorhandling.ForeignException

All Implemented Interfaces:

Serializable
```
@InterfaceAudience.Public
@InterfaceStability.Evolving
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.

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

Methods
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.protobuf.generated.ErrorHandlingProtos.StackTraceElementMessage> traceList)` Unwind a serialized array of `ErrorHandlingProtos.StackTraceElementMessage`s to a `StackTraceElement`s.
`private static List<org.apache.hadoop.hbase.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.
    
    Parameters:
    source -
    cause -
  - ForeignException
```
public ForeignException(String source,
                String msg)
```
    Create a new ForeignException that can be serialized. It is assumed that this is locally generated.
    
    Parameters:
    source -
    msg -
- 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.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 com.google.protobuf.InvalidProtocolBufferException
```
    Takes a series of bytes and tries to generate an ForeignException instance for it.
    
    Parameters:
    bytes -
    
    Returns:
    the ForeignExcpetion instance
    
    Throws:
    
    com.google.protobuf.InvalidProtocolBufferException - if there was deserialization problem this is thrown.
  - toStackTrace
```
private static StackTraceElement[] toStackTrace(List<org.apache.hadoop.hbase.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).

Class ForeignException

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Throwable

Methods inherited from class java.lang.Object

Field Detail

source

Constructor Detail

ForeignException

ForeignException

Method Detail

getSource

isRemote

toString

toStackTraceElementMessages

serialize

deserialize

toStackTrace