Trail: JavaBeans(TM)
Lesson: Long Term Persistence

Long-term persistence is a model that enables beans to be saved in XML format.

Information on the XML format and on how to implement long-term persistence for non-beans can be found in XML Schema and Using XMLEncoder .

Encoder and Decoder

The XMLEncoder class is assigned to write output files for textual representation of Serializable objects. The following code fragment is an example of writing a Java bean and its properties in XML format:

     XMLEncoder encoder = new XMLEncoder(
                new BufferedOutputStream(
                        new FileOutputStream( "Beanarchive.xml" ) ) );

        encoder.writeObject( object );

The XMLDecoder class reads an XML document that was created with XMLEncoder:

      XMLDecoder decoder = new XMLDecoder(
                new BufferedInputStream(
                        new FileInputStream( "Beanarchive.xml" ) ) );

        Object object = decoder.readObject();

What's in XML?

An XML bean archive has its own specific syntax, which includes the following tags to represent each bean element:

The following code represents an XML archive that will be generated for the SimpleBean component:

<?xml version="1.0" encoding="UTF-8" ?>
  <object class="javax.swing.JFrame">
    <void method="add">
      <object class="java.awt.BorderLayout" field="CENTER"/>
      <object class="SimpleBean"/>
    <void property="defaultCloseOperation">
      <object class="javax.swing.WindowConstants" field="DISPOSE_ON_CLOSE"/>
    <void method="pack"/>
    <void property="visible">
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