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
Constructor | Description |
---|---|
Statement(Object target,
String methodName,
Object[] arguments) | Creates a new |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
void | execute() | The |
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 declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Constructor Detail
Statement
@ConstructorProperties({"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
Expression
s rather thanStatement
s 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 theArray
class.
- Throws:
-
NullPointerException
- if the value of thetarget
ormethodName
property isnull
-
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.