org.springframework.core

Class BridgeMethodResolver

java.lang.Object

org.springframework.core.BridgeMethodResolver

public abstract class BridgeMethodResolver
extends java.lang.Object

Helper for resolving synthetic bridge Methods to the Method being bridged.

Given a synthetic bridge Method returns the Method being bridged. A bridge method may be created by the compiler when extending a parameterized type whose methods have parameterized arguments. During runtime invocation the bridge Method may be invoked and/or used via reflection. When attempting to locate annotations on Methods, it is wise to check for bridge Methods as appropriate and find the bridged Method.

See The Java Language Specification for more details on the use of bridge methods.

Since:

2.0

Author:

Rob Harrop, Juergen Hoeller, Phillip Webb

Constructor Summary

Constructors

Constructor and Description
BridgeMethodResolver()

Method Summary

Modifier and Type	Method and Description
static java.lang.reflect.Method	findBridgedMethod(java.lang.reflect.Method bridgeMethod) Find the original method for the supplied bridge Method.
private static java.lang.reflect.Method	findGenericDeclaration(java.lang.reflect.Method bridgeMethod) Searches for the generic Method declaration whose erased signature matches that of the supplied bridge method.
private static boolean	isBridgedCandidateFor(java.lang.reflect.Method candidateMethod, java.lang.reflect.Method bridgeMethod) Returns true if the supplied 'candidateMethod' can be consider a validate candidate for the Method that is bridged by the supplied bridge Method.
(package private) static boolean	isBridgeMethodFor(java.lang.reflect.Method bridgeMethod, java.lang.reflect.Method candidateMethod, java.lang.Class<?> declaringClass) Determines whether or not the bridge Method is the bridge for the supplied candidate Method.
private static boolean	isResolvedTypeMatch(java.lang.reflect.Method genericMethod, java.lang.reflect.Method candidateMethod, java.lang.Class<?> declaringClass) Returns true if the Type signature of both the supplied generic Method and concrete Method are equal after resolving all types against the declaringType, otherwise returns false.
static boolean	isVisibilityBridgeMethodPair(java.lang.reflect.Method bridgeMethod, java.lang.reflect.Method bridgedMethod) Compare the signatures of the bridge method and the method which it bridges.
private static java.lang.reflect.Method	searchCandidates(java.util.List<java.lang.reflect.Method> candidateMethods, java.lang.reflect.Method bridgeMethod) Searches for the bridged method in the given candidates.
private static java.lang.reflect.Method	searchForMatch(java.lang.Class<?> type, java.lang.reflect.Method bridgeMethod) If the supplied Class has a declared Method whose signature matches that of the supplied Method, then this matching Method is returned, otherwise null is returned.

Methods inherited from class java.lang.Object

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

Constructor Detail

BridgeMethodResolver

public BridgeMethodResolver()

Method Detail

findBridgedMethod

public static java.lang.reflect.Method findBridgedMethod(java.lang.reflect.Method bridgeMethod)

Find the original method for the supplied bridge Method.

It is safe to call this method passing in a non-bridge Method instance. In such a case, the supplied Method instance is returned directly to the caller. Callers are not required to check for bridging before calling this method.

Parameters:

bridgeMethod - the method to introspect

Returns:

the original method (either the bridged method or the passed-in method if no more specific one could be found)

isBridgedCandidateFor

private static boolean isBridgedCandidateFor(java.lang.reflect.Method candidateMethod,
                                             java.lang.reflect.Method bridgeMethod)

Returns true if the supplied 'candidateMethod' can be consider a validate candidate for the Method that is bridged by the supplied bridge Method. This method performs inexpensive checks and can be used quickly filter for a set of possible matches.

searchCandidates

private static java.lang.reflect.Method searchCandidates(java.util.List<java.lang.reflect.Method> candidateMethods,
                                                         java.lang.reflect.Method bridgeMethod)

Searches for the bridged method in the given candidates.

Parameters:

candidateMethods - the List of candidate Methods

bridgeMethod - the bridge method

Returns:

the bridged method, or null if none found

isBridgeMethodFor

static boolean isBridgeMethodFor(java.lang.reflect.Method bridgeMethod,
                                 java.lang.reflect.Method candidateMethod,
                                 java.lang.Class<?> declaringClass)

Determines whether or not the bridge Method is the bridge for the supplied candidate Method.

findGenericDeclaration

private static java.lang.reflect.Method findGenericDeclaration(java.lang.reflect.Method bridgeMethod)

Searches for the generic Method declaration whose erased signature matches that of the supplied bridge method.

Throws:

java.lang.IllegalStateException - if the generic declaration cannot be found

isResolvedTypeMatch

private static boolean isResolvedTypeMatch(java.lang.reflect.Method genericMethod,
                                           java.lang.reflect.Method candidateMethod,
                                           java.lang.Class<?> declaringClass)

Returns true if the Type signature of both the supplied generic Method and concrete Method are equal after resolving all types against the declaringType, otherwise returns false.

searchForMatch

private static java.lang.reflect.Method searchForMatch(java.lang.Class<?> type,
                                                       java.lang.reflect.Method bridgeMethod)

If the supplied Class has a declared Method whose signature matches that of the supplied Method, then this matching Method is returned, otherwise null is returned.

isVisibilityBridgeMethodPair

public static boolean isVisibilityBridgeMethodPair(java.lang.reflect.Method bridgeMethod,
                                                   java.lang.reflect.Method bridgedMethod)

Compare the signatures of the bridge method and the method which it bridges. If the parameter and return types are the same, it is a 'visibility' bridge method introduced in Java 6 to fix http://bugs.sun.com/view_bug.do?bug_id=6342411. See also http://stas-blogspot.blogspot.com/2010/03/java-bridge-methods-explained.html

Returns:

whether signatures match as described