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Spring Cloud Contract Shaded Dependencies
package org.codehaus.plexus.util.introspection;
/*
* Copyright The Codehaus Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
/**
* @author Jason van Zyl
* @author Bob McWhirter
* @author Christoph Reck
* @author Geir Magnusson Jr.
* @author Attila Szegedi
*
*/
public class MethodMap
{
private static final int MORE_SPECIFIC = 0;
private static final int LESS_SPECIFIC = 1;
private static final int INCOMPARABLE = 2;
/**
* Keep track of all methods with the same name.
*/
Map> methodByNameMap = new Hashtable>();
/**
* 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.
*
* @param method The method
*/
public void add( Method method )
{
String methodName = method.getName();
List l = get( methodName );
if ( l == null )
{
l = new ArrayList();
methodByNameMap.put( methodName, l );
}
l.add( method );
}
/**
* Return a list of methods with the same name.
*
* @param key The name of the method.
* @return List list of methods
*/
public List get( String key )
{
return methodByNameMap.get( key );
}
/**
*
* 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.
*
*
* @param methodName name of method
* @param args the actual arguments with which the method is called
* @return the most specific applicable method, or null if no method is applicable.
* @throws AmbiguousException if there is more than one maximally specific applicable method
*/
public Method find( String methodName, Object[] args )
throws AmbiguousException
{
List methodList = get( methodName );
if ( methodList == null )
{
return null;
}
int l = args.length;
Class[] classes = new Class[l];
for ( int i = 0; i < l; ++i )
{
Object arg = args[i];
/*
* if we are careful down below, a null argument goes in there so we can know that the null was passed to
* the method
*/
classes[i] = arg == null ? null : arg.getClass();
}
return getMostSpecific( methodList, classes );
}
/**
* simple distinguishable exception, used when we run across ambiguous overloading
*/
public static class AmbiguousException
extends Exception
{
}
private static Method getMostSpecific( List methods, Class[] classes )
throws AmbiguousException
{
LinkedList applicables = getApplicables( methods, classes );
if ( applicables.isEmpty() )
{
return null;
}
if ( applicables.size() == 1 )
{
return applicables.getFirst();
}
/*
* This list will contain the maximally specific methods. Hopefully at the end of the below loop, the list will
* contain exactly one method, (the most specific method) otherwise we have ambiguity.
*/
LinkedList maximals = new LinkedList();
for ( Method app : applicables )
{
Class[] appArgs = app.getParameterTypes();
boolean lessSpecific = false;
for ( Iterator maximal = maximals.iterator(); !lessSpecific && maximal.hasNext(); )
{
Method max = maximal.next();
switch ( moreSpecific( appArgs, max.getParameterTypes() ) )
{
case MORE_SPECIFIC:
{
/*
* This method is more specific than the previously known maximally specific, so remove the old
* maximum.
*/
maximal.remove();
break;
}
case LESS_SPECIFIC:
{
/*
* This method is less specific than some of the currently known maximally specific methods, so
* we won't add it into the set of maximally specific methods
*/
lessSpecific = true;
break;
}
}
}
if ( !lessSpecific )
{
maximals.addLast( app );
}
}
if ( maximals.size() > 1 )
{
// We have more than one maximally specific method
throw new AmbiguousException();
}
return maximals.getFirst();
}
/**
* Determines which method signature (represented by a class array) is more specific. This defines a partial
* ordering on the method signatures.
*
* @param c1 first signature to compare
* @param c2 second signature to compare
* @return MORE_SPECIFIC if c1 is more specific than c2, LESS_SPECIFIC if c1 is less specific than c2, INCOMPARABLE
* if they are incomparable.
*/
private static int moreSpecific( Class[] c1, Class[] c2 )
{
boolean c1MoreSpecific = false;
boolean c2MoreSpecific = false;
for ( int i = 0; i < c1.length; ++i )
{
if ( c1[i] != c2[i] )
{
c1MoreSpecific = c1MoreSpecific || isStrictMethodInvocationConvertible( c2[i], c1[i] );
c2MoreSpecific = c2MoreSpecific || isStrictMethodInvocationConvertible( c1[i], c2[i] );
}
}
if ( c1MoreSpecific )
{
if ( c2MoreSpecific )
{
/*
* Incomparable due to cross-assignable arguments (i.e. foo(String, Object) vs. foo(Object, String))
*/
return INCOMPARABLE;
}
return MORE_SPECIFIC;
}
if ( c2MoreSpecific )
{
return LESS_SPECIFIC;
}
/*
* Incomparable due to non-related arguments (i.e. foo(Runnable) vs. foo(Serializable))
*/
return INCOMPARABLE;
}
/**
* Returns all methods that are applicable to actual argument types.
*
* @param methods list of all candidate methods
* @param classes the actual types of the arguments
* @return a list that contains only applicable methods (number of formal and actual arguments matches, and argument
* types are assignable to formal types through a method invocation conversion).
*/
private static LinkedList getApplicables( List methods, Class[] classes )
{
LinkedList list = new LinkedList();
for ( Object method1 : methods )
{
Method method = (Method) method1;
if ( isApplicable( method, classes ) )
{
list.add( method );
}
}
return list;
}
/**
* Returns true if the supplied method is applicable to actual argument types.
*
* @param method The method to check for applicability
* @param classes The arguments
* @return true if the method applies to the parameter types
*/
private static boolean isApplicable( Method method, Class[] classes )
{
Class[] methodArgs = method.getParameterTypes();
if ( methodArgs.length != classes.length )
{
return false;
}
for ( int i = 0; i < classes.length; ++i )
{
if ( !isMethodInvocationConvertible( methodArgs[i], classes[i] ) )
{
return false;
}
}
return true;
}
/**
* Determines whether a type represented by a class object is convertible to another type represented by a class
* object using a method invocation conversion, treating object types of primitive types as if they were primitive
* types (that is, a Boolean actual parameter type matches boolean primitive formal type). This behavior is because
* this method is used to determine applicable methods for an actual parameter list, and primitive types are
* represented by their object duals in reflective method calls.
*
* @param formal the formal parameter type to which the actual parameter type should be convertible
* @param actual the actual parameter type.
* @return true if either formal type is assignable from actual type, or formal is a primitive type and actual is
* its corresponding object type or an object type of a primitive type that can be converted to the formal
* type.
*/
private static boolean isMethodInvocationConvertible( Class formal, Class actual )
{
/*
* if it's a null, it means the arg was null
*/
if ( actual == null && !formal.isPrimitive() )
{
return true;
}
/*
* Check for identity or widening reference conversion
*/
if ( actual != null && formal.isAssignableFrom( actual ) )
{
return true;
}
/*
* Check for boxing with widening primitive conversion. Note that actual parameters are never primitives.
*/
if ( formal.isPrimitive() )
{
if ( formal == Boolean.TYPE && actual == Boolean.class )
return true;
if ( formal == Character.TYPE && actual == Character.class )
return true;
if ( formal == Byte.TYPE && actual == Byte.class )
return true;
if ( formal == Short.TYPE && ( actual == Short.class || actual == Byte.class ) )
return true;
if ( formal == Integer.TYPE
&& ( actual == Integer.class || actual == Short.class || actual == Byte.class ) )
return true;
if ( formal == Long.TYPE && ( actual == Long.class || actual == Integer.class || actual == Short.class
|| actual == Byte.class ) )
return true;
if ( formal == Float.TYPE && ( actual == Float.class || actual == Long.class || actual == Integer.class
|| actual == Short.class || actual == Byte.class ) )
return true;
if ( formal == Double.TYPE && ( actual == Double.class || actual == Float.class || actual == Long.class
|| actual == Integer.class || actual == Short.class || actual == Byte.class ) )
return true;
}
return false;
}
/**
* Determines whether a type represented by a class object is convertible to another type represented by a class
* object using a method invocation conversion, without matching object and primitive types. This method is used to
* determine the more specific type when comparing signatures of methods.
*
* @param formal the formal parameter type to which the actual parameter type should be convertible
* @param actual the actual parameter type.
* @return true if either formal type is assignable from actual type, or formal and actual are both primitive types
* and actual can be subject to widening conversion to formal.
*/
private static boolean isStrictMethodInvocationConvertible( Class formal, Class actual )
{
/*
* we shouldn't get a null into, but if so
*/
if ( actual == null && !formal.isPrimitive() )
{
return true;
}
/*
* Check for identity or widening reference conversion
*/
if ( formal.isAssignableFrom( actual ) )
{
return true;
}
/*
* Check for widening primitive conversion.
*/
if ( formal.isPrimitive() )
{
if ( formal == Short.TYPE && ( actual == Byte.TYPE ) )
return true;
if ( formal == Integer.TYPE && ( actual == Short.TYPE || actual == Byte.TYPE ) )
return true;
if ( formal == Long.TYPE && ( actual == Integer.TYPE || actual == Short.TYPE || actual == Byte.TYPE ) )
return true;
if ( formal == Float.TYPE
&& ( actual == Long.TYPE || actual == Integer.TYPE || actual == Short.TYPE || actual == Byte.TYPE ) )
return true;
if ( formal == Double.TYPE && ( actual == Float.TYPE || actual == Long.TYPE || actual == Integer.TYPE
|| actual == Short.TYPE || actual == Byte.TYPE ) )
return true;
}
return false;
}
}