org.eigenbase.util
Class ReflectUtil

java.lang.Object
  org.eigenbase.util.ReflectUtil

public abstract class ReflectUtil
extends Object

Static utilities for Java reflection.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/util/ReflectUtil.java#21 $

Author:

John V. Sichi

Field Summary

private static Map<Class,Class>	primitiveToBoxingMap
private static Map<Class,Method>	primitiveToByteBufferReadMethod
private static Map<Class,Method>	primitiveToByteBufferWriteMethod

Constructor Summary

ReflectUtil()

Method Summary

static <R extends ReflectiveVisitor,E> ReflectiveVisitDispatcher<R,E>	createDispatcher(Class<R> visitorBaseClazz, Class<E> visiteeBaseClazz) Creates a dispatcher for calls to lookupVisitMethod(java.lang.Class, java.lang.Class, java.lang.String).
static Class	getBoxingClass(Class primitiveClass) Gets the Java boxing class for a primitive class.
static Method	getByteBufferReadMethod(Class clazz) Uses reflection to find the correct java.nio.ByteBuffer "absolute get" method for a given primitive type.
static Method	getByteBufferWriteMethod(Class clazz) Uses reflection to find the correct java.nio.ByteBuffer "absolute put" method for a given primitive type.
static Class<?>	getClassForName(String name) Looks up a class by name.
static String	getUnmangledMethodName(Class declaringClass, String methodName, Class[] paramTypes) Composes a string representing a human-readable method name (with neither exception nor return type information).
static String	getUnmangledMethodName(Method method) Composes a string representing a human-readable method name (with neither exception nor return type information).
static String	getUnqualifiedClassName(Class c) Gets the name of a class with no package qualifiers; if it's an inner class, it will still be qualified by the containing class (X$Y).
static boolean	invokeVisitor(ReflectiveVisitor visitor, Object visitee, Class hierarchyRoot, String visitMethodName) Implements the Glossary.VisitorPattern via reflection.
private static boolean	invokeVisitorInternal(Object visitor, Object visitee, Class hierarchyRoot, String visitMethodName) Shared implementation of the two forms of invokeVisitor.
static Method	lookupVisitMethod(Class<?> visitorClass, Class<?> visiteeClass, String visitMethodName) Looks up a visit method.
private static Method	lookupVisitMethod(Class<?> visitorClass, Class<?> visiteeClass, String visitMethodName, Class<?>[] paramTypes, Map<Class<?>,Method> cache)
static Method	lookupVisitMethod(Class<?> visitorClass, Class<?> visiteeClass, String visitMethodName, List<Class> additionalParameterTypes) Looks up a visit method taking additional parameters beyond the overloaded visitee type.

Methods inherited from class java.lang.Object

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

Field Detail

primitiveToBoxingMap

private static Map<Class,Class> primitiveToBoxingMap

primitiveToByteBufferReadMethod

private static Map<Class,Method> primitiveToByteBufferReadMethod

primitiveToByteBufferWriteMethod

private static Map<Class,Method> primitiveToByteBufferWriteMethod

Constructor Detail

ReflectUtil

public ReflectUtil()

Method Detail

getByteBufferReadMethod

public static Method getByteBufferReadMethod(Class clazz)

Uses reflection to find the correct java.nio.ByteBuffer "absolute get" method for a given primitive type.

Parameters:

clazz - the Class object representing the primitive type

Returns:

corresponding method

getByteBufferWriteMethod

public static Method getByteBufferWriteMethod(Class clazz)

Uses reflection to find the correct java.nio.ByteBuffer "absolute put" method for a given primitive type.

Parameters:

clazz - the Class object representing the primitive type

Returns:

corresponding method

getBoxingClass

public static Class getBoxingClass(Class primitiveClass)

Gets the Java boxing class for a primitive class.

Parameters:

primitiveClass - representative class for primitive (e.g. java.lang.Integer.TYPE)

Returns:

corresponding boxing Class (e.g. java.lang.Integer)

getUnqualifiedClassName

public static String getUnqualifiedClassName(Class c)

Gets the name of a class with no package qualifiers; if it's an inner class, it will still be qualified by the containing class (X$Y).

Parameters:

c - the class of interest

Returns:

the unqualified name

getUnmangledMethodName

public static String getUnmangledMethodName(Class declaringClass,
                                            String methodName,
                                            Class[] paramTypes)

Composes a string representing a human-readable method name (with neither exception nor return type information).

Parameters:

declaringClass - class on which method is defined

methodName - simple name of method without signature

paramTypes - method parameter types

Returns:

unmangled method name

getUnmangledMethodName

public static String getUnmangledMethodName(Method method)

Composes a string representing a human-readable method name (with neither exception nor return type information).

Parameters:

method - method whose name is to be generated

Returns:

unmangled method name

invokeVisitor

public static boolean invokeVisitor(ReflectiveVisitor visitor,
                                    Object visitee,
                                    Class hierarchyRoot,
                                    String visitMethodName)

Implements the Glossary.VisitorPattern via reflection. The basic technique is taken from a Javaworld article. For an example of how to use it, see ReflectVisitorTest. Visit method lookup follows the same rules as if compile-time resolution for VisitorClass.visit(VisiteeClass) were performed. An ambiguous match due to multiple interface inheritance results in an IllegalArgumentException. A non-match is indicated by returning false.

Parameters:

visitor - object whose visit method is to be invoked

visitee - object to be passed as a parameter to the visit method

hierarchyRoot - if non-null, visitor method will only be invoked if it takes a parameter whose type is a subtype of hierarchyRoot

visitMethodName - name of visit method, e.g. "visit"

Returns:

true if a matching visit method was found and invoked

invokeVisitorInternal

private static boolean invokeVisitorInternal(Object visitor,
                                             Object visitee,
                                             Class hierarchyRoot,
                                             String visitMethodName)

Shared implementation of the two forms of invokeVisitor.

Parameters:

visitor - object whose visit method is to be invoked

visitee - object to be passed as a parameter to the visit method

hierarchyRoot - if non-null, visitor method will only be invoked if it takes a parameter whose type is a subtype of hierarchyRoot

visitMethodName - name of visit method, e.g. "visit"

Returns:

true if a matching visit method was found and invoked

lookupVisitMethod

public static Method lookupVisitMethod(Class<?> visitorClass,
                                       Class<?> visiteeClass,
                                       String visitMethodName)

Looks up a visit method.

Parameters:

visitorClass - class of object whose visit method is to be invoked

visiteeClass - class of object to be passed as a parameter to the visit method

visitMethodName - name of visit method

Returns:

method found, or null if none found

lookupVisitMethod

public static Method lookupVisitMethod(Class<?> visitorClass,
                                       Class<?> visiteeClass,
                                       String visitMethodName,
                                       List<Class> additionalParameterTypes)

Looks up a visit method taking additional parameters beyond the overloaded visitee type.

Parameters:

visitorClass - class of object whose visit method is to be invoked

visiteeClass - class of object to be passed as a parameter to the visit method

visitMethodName - name of visit method

additionalParameterTypes - list of additional parameter types

Returns:

method found, or null if none found

See Also:

createDispatcher(Class,Class)

lookupVisitMethod

private static Method lookupVisitMethod(Class<?> visitorClass,
                                        Class<?> visiteeClass,
                                        String visitMethodName,
                                        Class<?>[] paramTypes,
                                        Map<Class<?>,Method> cache)

createDispatcher

public static <R extends ReflectiveVisitor,E> ReflectiveVisitDispatcher<R,E> createDispatcher(Class<R> visitorBaseClazz,
                                                                                              Class<E> visiteeBaseClazz)

Creates a dispatcher for calls to lookupVisitMethod(java.lang.Class, java.lang.Class, java.lang.String). The dispatcher caches methods between invocations.

Parameters:

visitorBaseClazz - Visitor base class

visiteeBaseClazz - Visitee base class

Returns:

cache of methods

getClassForName

public static Class<?> getClassForName(String name)
                                throws Exception

Looks up a class by name. This is like Class.forName, except that it handles primitive type names.

Parameters:

name - fully-qualified name of class to look up

Returns:

class

Throws:

Exception