ReflectUtil (Apache Ant API)
Description: declaration: package: org.apache.tools.ant.util, class: ReflectUtil

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.