Package org.apache.tools.ant.util

Class ReflectUtil

java.lang.Object

org.apache.tools.ant.util.ReflectUtil

public class ReflectUtil
extends Object

Utility class to handle reflection on java objects. The class contains static methods to call reflection methods, catch any exceptions, converting them to BuildExceptions.

Method Summary

Modifier and Type	Method	Description
static <T> T	getField(Object obj, String fieldName)	Get the value of a field in an object.
static <T> T	invoke(Object obj, String methodName)	Call a method on the object with no parameters.
static <T> T	invoke(Object obj, String methodName, Class<?> argType, Object arg)	Call a method on the object with one argument.
static <T> T	invoke(Object obj, String methodName, Class<?> argType1, Object arg1, Class<?> argType2, Object arg2)	Call a method on the object with two argument.
static <T> T	invokeStatic(Object obj, String methodName)	Call a method on the object with no parameters.
static <T> T	newInstance(Class<T> ofClass, Class<?>[] argTypes, Object[] args)	Create an instance of a class using the constructor matching the given arguments.
static boolean	respondsTo(Object o, String methodName)	A method to test if an object responds to a given message (method call)
static void	throwBuildException(Exception t)	A method to convert an invocationTargetException to a BuildException and throw it.
static BuildException	toBuildException(Exception t)	A method to convert an invocationTargetException to a BuildException.

Methods inherited from class java.lang.Object

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

Method Details

newInstance

public static <T> T newInstance(Class<T> ofClass,
 Class<?>[] argTypes,
 Object[] args)

Create an instance of a class using the constructor matching the given arguments.

Type Parameters:

T - desired type

Parameters:

ofClass - Class<T>

argTypes - Class<?>[]

args - Object[]

Returns:

class instance

Since:

Ant 1.8.0

invoke

public static <T> T invoke(Object obj,
 String methodName)

Call a method on the object with no parameters.

Type Parameters:

T - desired type

Parameters:

obj - the object to invoke the method on.

methodName - the name of the method to call

Returns:

the object returned by the method

invokeStatic

public static <T> T invokeStatic(Object obj,
 String methodName)

Call a method on the object with no parameters. Note: Unlike the invoke method above, this calls class or static methods, not instance methods.

Type Parameters:

T - desired type

Parameters:

obj - the object to invoke the method on.

methodName - the name of the method to call

Returns:

the object returned by the method

invoke

public static <T> T invoke(Object obj,
 String methodName,
 Class<?> argType,
 Object arg)

Call a method on the object with one argument.

Type Parameters:

T - desired type

Parameters:

obj - the object to invoke the method on.

methodName - the name of the method to call

argType - the type of argument.

arg - the value of the argument.

Returns:

the object returned by the method

invoke

public static <T> T invoke(Object obj,
 String methodName,
 Class<?> argType1,
 Object arg1,
 Class<?> argType2,
 Object arg2)

Call a method on the object with two argument.

Type Parameters:

T - desired type

Parameters:

obj - the object to invoke the method on.

methodName - the name of the method to call

argType1 - the type of the first argument.

arg1 - the value of the first argument.

argType2 - the type of the second argument.

arg2 - the value of the second argument.

Returns:

the object returned by the method

getField

public static <T> T getField(Object obj,
 String fieldName)
                      throws BuildException

Get the value of a field in an object.

Type Parameters:

T - desired type

Parameters:

obj - the object to look at.

fieldName - the name of the field in the object.

Returns:

the value of the field.

Throws:

BuildException - if there is an error.

throwBuildException

public static void throwBuildException(Exception t)
                                throws BuildException

A method to convert an invocationTargetException to a BuildException and throw it.

Parameters:

t - the invocation target exception.

Throws:

BuildException - the converted exception.

toBuildException

public static BuildException toBuildException(Exception t)

A method to convert an invocationTargetException to a BuildException.

Parameters:

t - the invocation target exception.

Returns:

the converted exception.

Since:

ant 1.7.1

respondsTo

public static boolean respondsTo(Object o,
 String methodName)
                          throws BuildException

A method to test if an object responds to a given message (method call)

Parameters:

o - the object

methodName - the method to check for

Returns:

true if the object has the method.

Throws:

BuildException - if there is a problem.