package bboss.org.apache.velocity.util.introspection;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
/**
*
* @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
* @author <a href="mailto:bob@werken.com">Bob McWhirter</a>
* @author <a href="mailto:Christoph.Reck@dlr.de">Christoph Reck</a>
* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
* @author <a href="mailto:szegedia@freemail.hu">Attila Szegedi</a>
* @author Nathan Bubna
* @version $Id: IntrospectionUtils.java 476785 2006-11-19 10:06:21Z henning $
* @since 1.6
*/
public class IntrospectionUtils
{
/**
* 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.
* @param possibleVarArg whether or not we're dealing with the last parameter
* in the method declaration
* @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.
*/
public static boolean isMethodInvocationConvertible(Class formal,
Class actual,
boolean possibleVarArg)
{
/* 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;
}
/* Check for vararg conversion. */
if (possibleVarArg && formal.isArray())
{
if (actual.isArray())
{
actual = actual.getComponentType();
}
return isMethodInvocationConvertible(formal.getComponentType(),
actual, false);
}
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.
* @param possibleVarArg whether or not we're dealing with the last parameter
* in the method declaration
* @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.
*/
public static boolean isStrictMethodInvocationConvertible(Class formal,
Class actual,
boolean possibleVarArg)
{
/* 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;
}
/* Check for vararg conversion. */
if (possibleVarArg && formal.isArray())
{
if (actual.isArray())
{
actual = actual.getComponentType();
}
return isStrictMethodInvocationConvertible(formal.getComponentType(),
actual, false);
}
return false;
}
}