XMLDecoder (Java SE 21 & JDK 21)
Description: declaration: module: java.desktop, package: java.beans, class: XMLDecoder
Keywords: java.beans.XMLDecoder class

Module java.desktop
Package java.beans

# Class XMLDecoder

java.lang.Object
java.beans.XMLDecoder

All Implemented Interfaces:
  `AutoCloseable`

public class XMLDecoder extends Object implements AutoCloseable
The `XMLDecoder` class is used to read XML documents created using the `XMLEncoder` and is used just like the `ObjectInputStream`. For example, one can use the following fragment to read the first object defined in an XML document written by the `XMLEncoder` class:

           XMLDecoder d = new XMLDecoder(
                              new BufferedInputStream(
                                  new FileInputStream("Test.xml")));
           Object result = d.readObject();
           d.close();

For more information you might also want to check out Long Term Persistence of JavaBeans Components: XML Schema, an article in The Swing Connection.

Since:
  1.4
See Also:
  - `XMLEncoder`
  - `ObjectInputStream`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `XMLDecoder(InputStream in)`
  Creates a new input stream for reading archives created by the `XMLEncoder` class.
  `XMLDecoder(InputStream in, Object owner)`
  Creates a new input stream for reading archives created by the `XMLEncoder` class.
  `XMLDecoder(InputStream in, Object owner, ExceptionListener exceptionListener)`
  Creates a new input stream for reading archives created by the `XMLEncoder` class.
  `XMLDecoder(InputStream in, Object owner, ExceptionListener exceptionListener, ClassLoader cl)`
  Creates a new input stream for reading archives created by the `XMLEncoder` class.
  `XMLDecoder(InputSource is)`
  Creates a new decoder to parse XML archives created by the `XMLEncoder` class.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `close()`
  This method closes the input stream associated with this stream.
  `static DefaultHandler`
  `createHandler(Object owner, ExceptionListener el, ClassLoader cl)`
  Creates a new handler for SAX parser that can be used to parse embedded XML archives created by the `XMLEncoder` class.
  `ExceptionListener`
  `getExceptionListener()`
  Gets the exception handler for this stream.
  `Object`
  `getOwner()`
  Gets the owner of this decoder.
  `Object`
  `readObject()`
  Reads the next object from the underlying input stream.
  `void`
  `setExceptionListener(ExceptionListener exceptionListener)`
  Sets the exception handler for this stream to `exceptionListener`.
  `void`
  `setOwner(Object owner)`
  Sets the owner of this decoder to `owner`.

  ### Methods declared in class java.lang.Object

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

- ## Constructor Details

  - ### XMLDecoder

    public XMLDecoder(InputStream in)
    Creates a new input stream for reading archives created by the `XMLEncoder` class.
    Parameters:
      `in` - The underlying stream.
    See Also:
      - `XMLEncoder(java.io.OutputStream)`

  - ### XMLDecoder

    public XMLDecoder(InputStream in, Object owner)
    Creates a new input stream for reading archives created by the `XMLEncoder` class.
    Parameters:
      `in` - The underlying stream.
      `owner` - The owner of this stream.

  - ### XMLDecoder

    public XMLDecoder(InputStream in, Object owner, ExceptionListener exceptionListener)
    Creates a new input stream for reading archives created by the `XMLEncoder` class.
    Parameters:
      `in` - the underlying stream.
      `owner` - the owner of this stream.
      `exceptionListener` - the exception handler for the stream; if `null` the default exception listener will be used.

  - ### XMLDecoder

    public XMLDecoder(InputStream in, Object owner, ExceptionListener exceptionListener, ClassLoader cl)
    Creates a new input stream for reading archives created by the `XMLEncoder` class.
    Parameters:
      `in` - the underlying stream. `null` may be passed without error, though the resulting XMLDecoder will be useless
      `owner` - the owner of this stream. `null` is a legal value
      `exceptionListener` - the exception handler for the stream, or `null` to use the default
      `cl` - the class loader used for instantiating objects. `null` indicates that the default class loader should be used
    Since:
      1.5

  - ### XMLDecoder

    public XMLDecoder(InputSource is)
    Creates a new decoder to parse XML archives created by the `XMLEncoder` class. If the input source `is` is `null`, no exception is thrown and no parsing is performed. This behavior is similar to behavior of other constructors that use `InputStream` as a parameter.
    Parameters:
      `is` - the input source to parse
    Since:
      1.7

- ## Method Details

  - ### close

    public void close()
    This method closes the input stream associated with this stream.
    Specified by:
      `close` in interface `AutoCloseable`

  - ### setExceptionListener

    public void setExceptionListener(ExceptionListener exceptionListener)
    Sets the exception handler for this stream to `exceptionListener`. The exception handler is notified when this stream catches recoverable exceptions.
    Parameters:
      `exceptionListener` - The exception handler for this stream; if `null` the default exception listener will be used.
    See Also:
      - `getExceptionListener()`

  - ### getExceptionListener

    public ExceptionListener getExceptionListener()
    Gets the exception handler for this stream.
    Returns:
      The exception handler for this stream. Will return the default exception listener if this has not explicitly been set.
    See Also:
      - `setExceptionListener(java.beans.ExceptionListener)`

  - ### readObject

    public Object readObject()
    Reads the next object from the underlying input stream.
    Returns:
      the next object read
    Throws:
      `ArrayIndexOutOfBoundsException` - if the stream contains no objects (or no more objects)
    See Also:
      - `XMLEncoder.writeObject(java.lang.Object)`

  - ### setOwner

    public void setOwner(Object owner)
    Sets the owner of this decoder to `owner`.
    Parameters:
      `owner` - The owner of this decoder.
    See Also:
      - `getOwner()`

  - ### getOwner

    public Object getOwner()
    Gets the owner of this decoder.
    Returns:
      The owner of this decoder.
    See Also:
      - `setOwner(java.lang.Object)`

  - ### createHandler

    public static DefaultHandler createHandler(Object owner, ExceptionListener el, ClassLoader cl)
    Creates a new handler for SAX parser that can be used to parse embedded XML archives created by the `XMLEncoder` class. The `owner` should be used if parsed XML document contains the method call within context of the <java> element. The `null` value may cause illegal parsing in such case. The same problem may occur, if the `owner` class does not contain expected method to call. See details here.
    Parameters:
      `owner` - the owner of the default handler that can be used as a value of <java> element
      `el` - the exception handler for the parser, or `null` to use the default exception handler
      `cl` - the class loader used for instantiating objects, or `null` to use the default class loader
    Returns:
      an instance of `DefaultHandler` for SAX parser
    Since:
      1.7