Class CompositeDataInvocationHandler

java.lang.Object

javax.management.openmbean.CompositeDataInvocationHandler

All Implemented Interfaces:

InvocationHandler

public class CompositeDataInvocationHandler
extends Object
implements InvocationHandler

An InvocationHandler that forwards getter methods to a CompositeData. If you have an interface that contains only getter methods (such as String getName() or boolean isActive()) then you can use this class in conjunction with the Proxy class to produce an implementation of the interface where each getter returns the value of the corresponding item in a CompositeData.

For example, suppose you have an interface like this:

public interface NamedNumber {
    public int getNumber();
    public String getName();
}

and a CompositeData constructed like this:

CompositeData cd =
    new CompositeDataSupport(
        someCompositeType,
        new String[] {"number", "name"},
        new Object[] {5, "five"}
    );

then you can construct an object implementing NamedNumber and backed by the object cd like this:

InvocationHandler handler =
    new CompositeDataInvocationHandler(cd);
NamedNumber nn = (NamedNumber)
    Proxy.newProxyInstance(NamedNumber.class.getClassLoader(),
                           new Class[] {NamedNumber.class},
                           handler);

A call to nn.getNumber() will then return 5.

If the first letter of the property defined by a getter is a capital, then this handler will look first for an item in the CompositeData beginning with a capital, then, if that is not found, for an item beginning with the corresponding lowercase letter or code point. For a getter called getNumber(), the handler will first look for an item called Number, then for number. If the getter is called getnumber(), then the item must be called number.

If the method given to invoke is the method boolean equals(Object) inherited from Object, then it will return true if and only if the argument is a Proxy whose InvocationHandler is also a CompositeDataInvocationHandler and whose backing CompositeData is equal (not necessarily identical) to this object's. If the method given to invoke is the method int hashCode() inherited from Object, then it will return a value that is consistent with this definition of equals: if two objects are equal according to equals, then they will have the same hashCode.

Since:

1.6

Constructor Summary

Constructors

Constructor	Description
CompositeDataInvocationHandler(CompositeData compositeData)	Construct a handler backed by the given CompositeData.

Method Summary

Modifier and Type	Method	Description
CompositeData	getCompositeData()	Return the CompositeData that was supplied to the constructor.
Object	invoke(Object proxy, Method method, Object[] args)	Processes a method invocation on a proxy instance and returns the result.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

CompositeDataInvocationHandler

public CompositeDataInvocationHandler(CompositeData compositeData)

Construct a handler backed by the given CompositeData.

Parameters:

compositeData - the CompositeData that will supply information to getters.

Throws:

IllegalArgumentException - if compositeData is null.

Method Details

getCompositeData

public CompositeData getCompositeData()

Return the CompositeData that was supplied to the constructor.

Returns:

the CompositeData that this handler is backed by. This is never null.

invoke

public Object invoke(Object proxy,
 Method method,
 Object[] args)
              throws Throwable

Description copied from interface: InvocationHandler

Processes a method invocation on a proxy instance and returns the result. This method will be invoked on an invocation handler when a method is invoked on a proxy instance that it is associated with.

Specified by:

invoke in interface InvocationHandler

Parameters:

proxy - the proxy instance that the method was invoked on

method - the Method instance corresponding to the method invoked on the proxy instance; the declaring class of the Method object may be a proxy interface, one of their superinterfaces, or the Object class

args - an array of objects containing the values of the arguments passed in the method invocation on the proxy instance, or null if the invoked method takes no arguments. Arguments of primitive types are wrapped in instances of the appropriate primitive wrapper class, such as java.lang.Integer or java.lang.Boolean.

Returns:

the value to return from the method invocation on the proxy instance. If the declared return type of the invoked method is a primitive type, then the value returned by this method must be an instance of the corresponding primitive wrapper class; otherwise, it must be a type assignable to the declared return type. If the value returned by this method is null and the invoked method's return type is primitive, then a NullPointerException will be thrown by the method invocation on the proxy instance. If the value returned by this method is otherwise not compatible with the invoked method's declared return type as described above, a ClassCastException will be thrown by the method invocation on the proxy instance.

Throws:

Throwable - the exception to throw from the method invocation on the proxy instance. The exception's type must be assignable either to any of the exception types declared in the throws clause of the invoked method or to the unchecked exception types java.lang.RuntimeException or java.lang.Error. If a checked exception is thrown by this method that is not assignable to any of the exception types declared in the throws clause of the invoked method, then an UndeclaredThrowableException containing the exception that was thrown by this method will be thrown by the method invocation on the proxy instance.

See Also:

• UndeclaredThrowableException