weka.core
Class SerializationHelper

java.lang.Object
  extended by weka.core.SerializationHelper
All Implemented Interfaces:
RevisionHandler

public class SerializationHelper
extends java.lang.Object
implements RevisionHandler

A helper class for determining serialVersionUIDs and checking whether classes contain one and/or need one. One can also serialize and deserialize objects to and fro files or streams.

Version:
$Revision: 8597 $
Author:
fracpete (fracpete at waikato dot ac dot nz)

Field Summary
static java.lang.String SERIAL_VERSION_UID
          the field name of serialVersionUID.
 
Constructor Summary
SerializationHelper()
           
 
Method Summary
 java.lang.String getRevision()
          Returns the revision string.
static long getUID(java.lang.Class c)
          reads or creates the serialVersionUID for the given class.
static long getUID(java.lang.String classname)
          reads or creates the serialVersionUID for the given class.
static boolean hasUID(java.lang.Class c)
          checks whether the given class contains a serialVersionUID.
static boolean hasUID(java.lang.String classname)
          checks whether the given class contains a serialVersionUID.
static boolean isSerializable(java.lang.Class c)
          checks whether a class is serializable.
static boolean isSerializable(java.lang.String classname)
          checks whether a class is serializable.
static void main(java.lang.String[] args)
          Outputs information about a class on the commandline, takes class name as arguments.
static boolean needsUID(java.lang.Class c)
          checks whether a class needs to declare a serialVersionUID, i.e., it implements the java.io.Serializable interface but doesn't declare a serialVersionUID.
static boolean needsUID(java.lang.String classname)
          checks whether a class needs to declare a serialVersionUID, i.e., it implements the java.io.Serializable interface but doesn't declare a serialVersionUID.
static java.lang.Object read(java.io.InputStream stream)
          deserializes from the given stream and returns the object from it.
static java.lang.Object read(java.lang.String filename)
          deserializes the given file and returns the object from it.
static java.lang.Object[] readAll(java.io.InputStream stream)
          deserializes from the given stream and returns the object from it.
static java.lang.Object[] readAll(java.lang.String filename)
          deserializes the given file and returns the objects from it.
static void write(java.io.OutputStream stream, java.lang.Object o)
          serializes the given object to the specified stream.
static void write(java.lang.String filename, java.lang.Object o)
          serializes the given object to the specified file.
static void writeAll(java.io.OutputStream stream, java.lang.Object[] o)
          serializes the given objects to the specified stream.
static void writeAll(java.lang.String filename, java.lang.Object[] o)
          serializes the given objects to the specified file.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

SERIAL_VERSION_UID

public static final java.lang.String SERIAL_VERSION_UID
the field name of serialVersionUID.

See Also:
Constant Field Values
Constructor Detail

SerializationHelper

public SerializationHelper()
Method Detail

isSerializable

public static boolean isSerializable(java.lang.String classname)
checks whether a class is serializable.

Parameters:
classname - the class to check
Returns:
true if the class or one of its ancestors implements the Serializable interface, otherwise false (also if the class cannot be loaded)

isSerializable

public static boolean isSerializable(java.lang.Class c)
checks whether a class is serializable.

Parameters:
c - the class to check
Returns:
true if the class or one of its ancestors implements the Serializable interface, otherwise false

hasUID

public static boolean hasUID(java.lang.String classname)
checks whether the given class contains a serialVersionUID.

Parameters:
classname - the class to check
Returns:
true if the class contains a serialVersionUID, otherwise false (also if the class is not implementing serializable or cannot be loaded)

hasUID

public static boolean hasUID(java.lang.Class c)
checks whether the given class contains a serialVersionUID.

Parameters:
c - the class to check
Returns:
true if the class contains a serialVersionUID, otherwise false (also if the class is not implementing serializable)

needsUID

public static boolean needsUID(java.lang.String classname)
checks whether a class needs to declare a serialVersionUID, i.e., it implements the java.io.Serializable interface but doesn't declare a serialVersionUID.

Parameters:
classname - the class to check
Returns:
true if the class needs to declare one, false otherwise (also if the class cannot be loaded!)

needsUID

public static boolean needsUID(java.lang.Class c)
checks whether a class needs to declare a serialVersionUID, i.e., it implements the java.io.Serializable interface but doesn't declare a serialVersionUID.

Parameters:
c - the class to check
Returns:
true if the class needs to declare one, false otherwise

getUID

public static long getUID(java.lang.String classname)
reads or creates the serialVersionUID for the given class.

Parameters:
classname - the class to get the serialVersionUID for
Returns:
the UID, 0L for non-serializable classes (or if the class cannot be loaded)

getUID

public static long getUID(java.lang.Class c)
reads or creates the serialVersionUID for the given class.

Parameters:
c - the class to get the serialVersionUID for
Returns:
the UID, 0L for non-serializable classes

write

public static void write(java.lang.String filename,
                         java.lang.Object o)
                  throws java.lang.Exception
serializes the given object to the specified file.

Parameters:
filename - the file to write the object to
o - the object to serialize
Throws:
java.lang.Exception - if serialization fails

write

public static void write(java.io.OutputStream stream,
                         java.lang.Object o)
                  throws java.lang.Exception
serializes the given object to the specified stream.

Parameters:
stream - the stream to write the object to
o - the object to serialize
Throws:
java.lang.Exception - if serialization fails

writeAll

public static void writeAll(java.lang.String filename,
                            java.lang.Object[] o)
                     throws java.lang.Exception
serializes the given objects to the specified file.

Parameters:
filename - the file to write the object to
o - the objects to serialize
Throws:
java.lang.Exception - if serialization fails

writeAll

public static void writeAll(java.io.OutputStream stream,
                            java.lang.Object[] o)
                     throws java.lang.Exception
serializes the given objects to the specified stream.

Parameters:
stream - the stream to write the object to
o - the objects to serialize
Throws:
java.lang.Exception - if serialization fails

read

public static java.lang.Object read(java.lang.String filename)
                             throws java.lang.Exception
deserializes the given file and returns the object from it.

Parameters:
filename - the file to deserialize from
Returns:
the deserialized object
Throws:
java.lang.Exception - if deserialization fails

read

public static java.lang.Object read(java.io.InputStream stream)
                             throws java.lang.Exception
deserializes from the given stream and returns the object from it.

Parameters:
stream - the stream to deserialize from
Returns:
the deserialized object
Throws:
java.lang.Exception - if deserialization fails

readAll

public static java.lang.Object[] readAll(java.lang.String filename)
                                  throws java.lang.Exception
deserializes the given file and returns the objects from it.

Parameters:
filename - the file to deserialize from
Returns:
the deserialized objects
Throws:
java.lang.Exception - if deserialization fails

readAll

public static java.lang.Object[] readAll(java.io.InputStream stream)
                                  throws java.lang.Exception
deserializes from the given stream and returns the object from it.

Parameters:
stream - the stream to deserialize from
Returns:
the deserialized object
Throws:
java.lang.Exception - if deserialization fails

getRevision

public java.lang.String getRevision()
Returns the revision string.

Specified by:
getRevision in interface RevisionHandler
Returns:
the revision

main

public static void main(java.lang.String[] args)
                 throws java.lang.Exception
Outputs information about a class on the commandline, takes class name as arguments.

Parameters:
args - the classnames to check
Throws:
java.lang.Exception - if something goes wrong