java.beans

Class Statement

java.lang.Object

java.beans.Statement

Direct Known Subclasses:

Expression

public class Statement
extends Object

A 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)". Note that where this example uses names to denote the target and its argument, a statement object does not require a name space and is constructed with the values themselves. The statement object associates the named method with its environment as a simple set of values: the target and an array of argument values.

Since:

1.4

Constructor Summary

Constructors

Constructor and Description
Statement(Object target, String methodName, Object[] arguments) Creates a new Statement object for the specified target object to invoke the method specified by the name and by the array of arguments.

Method Summary

Modifier and Type	Method and Description
void	execute() The execute method finds a method whose name is the same as the methodName property, and invokes the method on the target.
Object[]	getArguments() Returns the arguments for the method to invoke.
String	getMethodName() Returns the name of the method to invoke.
Object	getTarget() Returns the target object of this statement.
String	toString() Prints the value of this statement using a Java-style syntax.

Methods inherited from class java.lang.Object

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

Constructor Detail

Statement

@ConstructorProperties(value={"target","methodName","arguments"})
public Statement(Object target,
                                                                                   String methodName,
                                                                                   Object[] arguments)

Creates a new Statement object for the specified target object to invoke the method specified by the name and by the array of arguments.

The target and the methodName values should not be null. Otherwise an attempt to execute this Expression will result in a NullPointerException. If the arguments value is null, an empty array is used as the value of the arguments property.

Parameters:

target - the target object of this statement

methodName - the name of the method to invoke on the specified target

arguments - the array of arguments to invoke the specified method

Method Detail

getTarget

public Object getTarget()

Returns the target object of this statement. If this method returns null, the execute() method throws a NullPointerException.

Returns:

the target object of this statement

getMethodName

public String getMethodName()

Returns the name of the method to invoke. If this method returns null, the execute() method throws a NullPointerException.

Returns:

the name of the method

getArguments

public Object[] getArguments()

Returns the arguments for the method to invoke. The number of arguments and their types must match the method being called. null can be used as a synonym of an empty array.

Returns:

the array of arguments

execute

public void execute()
             throws Exception

The execute method finds a method whose name is the same as the methodName property, and invokes the method on the target. When the target's class defines many methods with the given name the implementation should choose the most specific method using the algorithm specified in the Java Language Specification (15.11). The dynamic class of the target and arguments are used in place of the compile-time type information and, like the Method class itself, conversion between primitive values and their associated wrapper classes is handled internally.

The following method types are handled as special cases:

• Static methods may be called by using a class object as the target.
• The reserved method name "new" may be used to call a class's constructor as if all classes defined static "new" methods. Constructor invocations are typically considered Expressions rather than Statements as they return a value.
• The method names "get" and "set" defined in the List interface may also be applied to array instances, mapping to the static methods of the same name in the Array class.

Throws:

NullPointerException - if the value of the target or methodName property is null

NoSuchMethodException - if a matching method is not found

SecurityException - if a security manager exists and it denies the method invocation

Exception - that is thrown by the invoked method

See Also:

Method

toString

public String toString()

Prints the value of this statement using a Java-style syntax.

Overrides:

toString in class Object

Returns:

a string representation of the object.