Package weka.core

Class 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

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

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      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