See: Description
BeanInfo interface to create a
BeanInfo class and provide explicit information about the methods, properties, events, and other features of your beans.
DefaultPersistenceDelegate is a concrete implementation of the abstract
PersistenceDelegate class and is the delegate used by default for classes about which no information is available.
Encoder is a class which can be used to create files or streams that encode the state of a collection of JavaBeans in terms of their public APIs.
EventHandler class provides support for dynamically generating event listeners whose methods execute a simple statement involving an incoming event object and a target object.
Expression object represents a primitive expression in which a single method is applied to a target and a set of arguments to return a result - as in
"a.getFoo()".
EventListenerProxy specifically for adding a
PropertyChangeListener with a "bound" property.
Statement object represents a primitive statement in which a single method is applied to a target and a set of arguments - as in
"a.setFoo(b)".
EventListenerProxy specifically for adding a
VetoableChangeListener with a "constrained" property.
XMLDecoder class is used to read XML documents created using the
XMLEncoder and is used just like the
ObjectInputStream.
XMLEncoder class is a complementary alternative to the
ObjectOutputStream and can used to generate a textual representation of a
JavaBean in the same way that the
ObjectOutputStream can be used to create binary representation of
Serializable objects.
value when the
Introspector constructs a
PropertyDescriptor or
EventSetDescriptor classes associated with the annotated code element.
PropertyChangeEvent). However, most of the classes in this package are meant to be used by a bean editor (that is, a development environment for customizing and putting together beans to create an application). In particular, these classes help the bean editor create a user interface that the user can use to customize the bean. For example, a bean may contain a property of a special type that a bean editor may not know how to handle. By using the
PropertyEditor interface, a bean developer can provide an editor for this special type.
To minimize the resources used by a bean, the classes used by bean editors are loaded only when the bean is being edited. They are not needed while the bean is running in an application and therefore not loaded. This information is kept in what's called a bean-info (see BeanInfo).
Unless explicitly stated, null values or empty Strings are not valid parameters for the methods in this package. You may expect to see exceptions if these parameters are used.
java.beans package provides support for
long-term persistence -- reading and writing a bean as a textual representation of its property values. The property values are treated as beans, and are recursively read or written to capture their publicly available state. This approach is suitable for long-term storage because it relies only on public API, rather than the likely-to-change private implementation.
Note: The persistence scheme cannot automatically instantiate custom inner classes, such as you might use for event handlers. By using theEventHandlerclass instead of inner classes for custom event handlers, you can avoid this problem.
You read and write beans in XML format using the XMLDecoder and XMLEncoder classes, respectively. One notable feature of the persistence scheme is that reading in a bean requires no special knowledge of the bean.
Writing out a bean, on the other hand, sometimes requires special knowledge of the bean's type. If the bean's state can be expressed using only the no-argument constructor and public getter and setter methods for properties, no special knowledge is required. Otherwise, the bean requires a custom persistence delegate -- an object that is in charge of writing out beans of a particular type. All classes provided in the JDK that descend from java.awt.Component, as well as all their properties, automatically have persistence delegates.
If you need (or choose) to provide a persistence delegate for a bean, you can do so either by using a DefaultPersistenceDelegate instance or by creating your own subclass of PersistenceDelegate. If the only reason a bean needs a persistence delegate is because you want to invoke the bean's constructor with property values as arguments, you can create the bean's persistence delegate with the one-argument DefaultPersistenceDelegate constructor. Otherwise, you need to implement your own persistence delegate, for which you're likely to need the following classes:
PersistenceDelegate
Statements and
Expressions are necessary to create the bean and restore its state.
Statement
Expression
Statement used for methods that return a value.
Once you create a persistence delegate, you register it using the setPersistenceDelegate method of XMLEncoder.