Package weka.core

Class SerializationHelper

java.lang.Object
weka.core.SerializationHelper
All Implemented Interfaces:
RevisionHandler
public class SerializationHelper extends 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 from files or streams.
Version:
$Revision: 14293 $
Author:
fracpete (fracpete at waikato dot ac dot nz)

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    SERIAL_VERSION_UID
    the field name of serialVersionUID.

  • Constructor Summary

    Constructors
    Constructor
    Description
    SerializationHelper()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static ClassLoader
    checkForThirdPartyClass(String className, WekaPackageLibIsolatingClassLoader l)
    Checks to see if the supplied package class loader (or any of its dependent package class loaders) has the given third party class.
    static ObjectInputStream
    getObjectInputStream(InputStream stream)
    Get a (Weka package classloader aware) ObjectInputStream instance for reading objects from the supplied input stream
    String
    getRevision()
    Returns the revision string.
    static long
    getUID(Class<?> c)
    reads or creates the serialVersionUID for the given class.
    static long
    getUID(String classname)
    reads or creates the serialVersionUID for the given class.
    static boolean
    hasUID(Class<?> c)
    checks whether the given class contains a serialVersionUID.
    static boolean
    hasUID(String classname)
    checks whether the given class contains a serialVersionUID.
    static boolean
    isSerializable(Class<?> c)
    checks whether a class is serializable.
    static boolean
    isSerializable(String classname)
    checks whether a class is serializable.
    static void
    main(String[] args)
    Outputs information about a class on the commandline, takes class name as arguments.
    static boolean
    needsUID(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(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 Object
    read(InputStream stream)
    deserializes from the given stream and returns the object from it.
    static Object
    read(String filename)
    deserializes the given file and returns the object from it.
    static Object[]
    readAll(InputStream stream)
    deserializes from the given stream and returns the object from it.
    static Object[]
    readAll(String filename)
    deserializes the given file and returns the objects from it.
    static void
    write(OutputStream stream, Object o)
    serializes the given object to the specified stream.
    static void
    write(String filename, Object o)
    serializes the given object to the specified file.
    static void
    writeAll(OutputStream stream, Object[] o)
    serializes the given objects to the specified stream.
    static void
    writeAll(String filename, 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 Details

    • SERIAL_VERSION_UID

      public static final String SERIAL_VERSION_UID
      the field name of serialVersionUID.
      See Also:

  • Constructor Details

    • SerializationHelper

      public SerializationHelper()

  • Method Details

    • isSerializable

      public static boolean isSerializable(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(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(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(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(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(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(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(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(String filename, Object o) throws Exception
      serializes the given object to the specified file.
      Parameters:
      filename - the file to write the object to
      o - the object to serialize
      Throws:
      Exception - if serialization fails

    • write

      public static void write(OutputStream stream, Object o) throws Exception
      serializes the given object to the specified stream.
      Parameters:
      stream - the stream to write the object to
      o - the object to serialize
      Throws:
      Exception - if serialization fails

    • writeAll

      public static void writeAll(String filename, Object[] o) throws Exception
      serializes the given objects to the specified file.
      Parameters:
      filename - the file to write the object to
      o - the objects to serialize
      Throws:
      Exception - if serialization fails

    • writeAll

      public static void writeAll(OutputStream stream, Object[] o) throws Exception
      serializes the given objects to the specified stream.
      Parameters:
      stream - the stream to write the object to
      o - the objects to serialize
      Throws:
      Exception - if serialization fails

    • read

      public static Object read(String filename) throws Exception
      deserializes the given file and returns the object from it.
      Parameters:
      filename - the file to deserialize from
      Returns:
      the deserialized object
      Throws:
      Exception - if deserialization fails

    • read

      public static Object read(InputStream stream) throws Exception
      deserializes from the given stream and returns the object from it.
      Parameters:
      stream - the stream to deserialize from
      Returns:
      the deserialized object
      Throws:
      Exception - if deserialization fails

    • checkForThirdPartyClass

      public static ClassLoader checkForThirdPartyClass(String className, WekaPackageLibIsolatingClassLoader l)
      Checks to see if the supplied package class loader (or any of its dependent package class loaders) has the given third party class.
      Parameters:
      className - the name of the third-party class to check for
      l - the third party class loader
      Returns:
      the class loader that owns the named third-party class, or null if not found.

    • getObjectInputStream

      public static ObjectInputStream getObjectInputStream(InputStream stream) throws IOException
      Get a (Weka package classloader aware) ObjectInputStream instance for reading objects from the supplied input stream
      Parameters:
      stream - the stream to wrap
      Returns:
      an ObjectInputStream instance that is aware of of Weka package classloaders
      Throws:
      IOException - if a problem occurs

    • readAll

      public static Object[] readAll(String filename) throws Exception
      deserializes the given file and returns the objects from it.
      Parameters:
      filename - the file to deserialize from
      Returns:
      the deserialized objects
      Throws:
      Exception - if deserialization fails

    • readAll

      public static Object[] readAll(InputStream stream) throws Exception
      deserializes from the given stream and returns the object from it.
      Parameters:
      stream - the stream to deserialize from
      Returns:
      the deserialized object
      Throws:
      Exception - if deserialization fails

    • getRevision

      public String getRevision()
      Returns the revision string.
      Specified by:
      getRevision in interface RevisionHandler
      Returns:
      the revision

    • main

      public static void main(String[] args) throws Exception
      Outputs information about a class on the commandline, takes class name as arguments.
      Parameters:
      args - the classnames to check
      Throws:
      Exception - if something goes wrong