Package org.apache.velocity.util.introspection

Class MethodMap

java.lang.Object

org.apache.velocity.util.introspection.MethodMap

public class MethodMap
extends Object

Version:

$Id$

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	MethodMap.AmbiguousException	Simple distinguishable exception, used when we run across ambiguous overloading.
private class	MethodMap.Match

Field Summary

Fields

Modifier and Type	Field	Description
(package private) TypeConversionHandler	conversionHandler
private static final int	EQUIVALENT
private static final int	EXPLICITLY_CONVERTIBLE
private static final int	IMPLCITLY_CONVERTIBLE
private static final int	INCOMPARABLE
private static final int	LESS_SPECIFIC
(package private) Map<String,List<Method>>	methodByNameMap	Keep track of all methods with the same name.
private static final int	MORE_SPECIFIC
private static final int	NOT_CONVERTIBLE
private static final int	STRICTLY_CONVERTIBLE

Constructor Summary

Constructors

Constructor	Description
MethodMap()	Default constructor
MethodMap(TypeConversionHandler conversionHandler)	Constructor with provided conversion handler

Method Summary

Modifier and Type	Method	Description
void	add(Method method)	Add a method to a list of methods by name.
private int	compare(Type[] t1, Type[] t2)	Determines which method signature (represented by a class array) is more specific.
Method	find(String methodName, Object[] args)	Find a method.
List<Method>	get(String key)	Return a list of methods with the same name.
private int	getApplicability(Method method, Class<?>[] classes)	Returns the applicability of the supplied method against actual argument types.
private Method	getBestMatch(List<Method> methods, Class<?>[] args)
private boolean	isConvertible(Type formal, Class<?> actual, boolean possibleVarArg)	Returns true if actual is convertible to formal by implicit Java method call conversions
private boolean	isExplicitlyConvertible(Type formal, Class<?> actual, boolean possibleVarArg)	Returns true if actual is convertible to formal using an explicit converter
private static boolean	isStrictConvertible(Type formal, Class<?> actual, boolean possibleVarArg)	Returns true if actual is strictly convertible to formal (aka without implicit boxing/unboxing)
private static boolean	onlyNullOrObjects(Class<?>[] args)

Methods inherited from class java.lang.Object

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

Field Details

INCOMPARABLE

private static final int INCOMPARABLE

See Also:

• Constant Field Values

MORE_SPECIFIC

private static final int MORE_SPECIFIC

See Also:

• Constant Field Values

EQUIVALENT

private static final int EQUIVALENT

See Also:

• Constant Field Values

LESS_SPECIFIC

private static final int LESS_SPECIFIC

See Also:

• Constant Field Values

NOT_CONVERTIBLE

private static final int NOT_CONVERTIBLE

See Also:

• Constant Field Values

EXPLICITLY_CONVERTIBLE

private static final int EXPLICITLY_CONVERTIBLE

See Also:

• Constant Field Values

IMPLCITLY_CONVERTIBLE

private static final int IMPLCITLY_CONVERTIBLE

See Also:

• Constant Field Values

STRICTLY_CONVERTIBLE

private static final int STRICTLY_CONVERTIBLE

See Also:

• Constant Field Values

conversionHandler

TypeConversionHandler conversionHandler

methodByNameMap

Map<String,List<Method>> methodByNameMap

Keep track of all methods with the same name.

Constructor Details

MethodMap

public MethodMap()

Default constructor

MethodMap

public MethodMap(TypeConversionHandler conversionHandler)

Constructor with provided conversion handler

Parameters:

conversionHandler - conversion handler

Since:

2.0

Method Details

add

public void add(Method method)

Add a method to a list of methods by name. For a particular class we are keeping track of all the methods with the same name.

Parameters:

method -

get

public List<Method> get(String key)

Return a list of methods with the same name.

Parameters:

key -

Returns:

List list of methods

find

public Method find(String methodName,
 Object[] args)
            throws MethodMap.AmbiguousException

Find a method. Attempts to find the most specific applicable method using the algorithm described in the JLS section 15.12.2 (with the exception that it can't distinguish a primitive type argument from an object type argument, since in reflection primitive type arguments are represented by their object counterparts, so for an argument of type (say) java.lang.Integer, it will not be able to decide between a method that takes int and a method that takes java.lang.Integer as a parameter.

This turns out to be a relatively rare case where this is needed - however, functionality like this is needed.

Parameters:

methodName - name of method

args - the actual arguments with which the method is called

Returns:

the most specific applicable method, or null if no method is applicable.

Throws:

MethodMap.AmbiguousException - if there is more than one maximally specific applicable method

onlyNullOrObjects

private static boolean onlyNullOrObjects(Class<?>[] args)

getBestMatch

private Method getBestMatch(List<Method> methods,
 Class<?>[] args)

compare

private int compare(Type[] t1,
 Type[] t2)

Determines which method signature (represented by a class array) is more specific. This defines a partial ordering on the method signatures.

Parameters:

t1 - first signature to compare

t2 - second signature to compare

Returns:

MORE_SPECIFIC if c1 is more specific than c2, LESS_SPECIFIC if c1 is less specific than c2, INCOMPARABLE if they are incomparable.

getApplicability

private int getApplicability(Method method,
 Class<?>[] classes)

Returns the applicability of the supplied method against actual argument types.

Parameters:

method - method that will be called

classes - arguments to method

Returns:

the level of applicability: 0 = not applicable 1 = explicitly applicable (i.e. using stock or custom conversion handlers) 2 = implicitly applicable (i.e. using JAva implicit boxing/unboxing and primitive types widening) 3 = strictly applicable

isConvertible

private boolean isConvertible(Type formal,
 Class<?> actual,
 boolean possibleVarArg)

Returns true if actual is convertible to formal by implicit Java method call conversions

Parameters:

formal -

actual -

possibleVarArg -

Returns:

convertible

isStrictConvertible

private static boolean isStrictConvertible(Type formal,
 Class<?> actual,
 boolean possibleVarArg)

Returns true if actual is strictly convertible to formal (aka without implicit boxing/unboxing)

Parameters:

formal -

actual -

possibleVarArg -

Returns:

convertible

isExplicitlyConvertible

private boolean isExplicitlyConvertible(Type formal,
 Class<?> actual,
 boolean possibleVarArg)

Returns true if actual is convertible to formal using an explicit converter

Parameters:

formal -

actual -

possibleVarArg -

Returns: