com.greenpepper.util.ClassUtils Maven / Gradle / Ivy
/*
* Copyright (c) 2006 Pyxis Technologies inc.
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA,
* or see the FSF site: http://www.fsf.org.
*/
package com.greenpepper.util;
import java.lang.reflect.Constructor;
import java.lang.reflect.Member;
import java.lang.reflect.Modifier;
/**
* ClassUtils class.
*
* @author oaouattara
* @version $Id: $Id
*/
public final class ClassUtils
{
/**
* loadClass.
*
* @param className a {@link java.lang.String} object.
* @param a T object.
* @return a {@link java.lang.Class} object.
* @throws java.lang.ClassNotFoundException if any.
*/
@SuppressWarnings("unchecked")
public static Class loadClass(String className)
throws ClassNotFoundException
{
return (Class) ClassUtils.class.getClassLoader().loadClass(className);
}
/**
* findBestTypedConstructor.
*
* @param klass a {@link java.lang.Class} object.
* @param args a {@link java.lang.Object} object.
* @param a T object.
* @return a {@link java.lang.reflect.Constructor} object.
* @throws java.lang.NoSuchMethodException if any.
*/
@SuppressWarnings("unchecked")
public static Constructor findBestTypedConstructor( Class klass, Object... args ) throws NoSuchMethodException
{
for (Constructor constructor : klass.getConstructors())
{
if (typesMatch( constructor, args )) return constructor;
}
throw noSuitableConstructorException(klass, args);
}
private static NoSuchMethodException noSuitableConstructorException(Class klass, Object... args)
{
return new NoSuchMethodException( klass.getName() + ".(" + toString( args ) + ")" );
}
/**
* findPossibleConstructor.
*
* @param klass a {@link java.lang.Class} object.
* @param args a {@link java.lang.Object} object.
* @param a T object.
* @return a {@link java.lang.reflect.Constructor} object.
* @throws java.lang.NoSuchMethodException if any.
*/
@SuppressWarnings({"unchecked"})
public static Constructor findPossibleConstructor( Class klass, Object... args ) throws NoSuchMethodException
{
for (Constructor constructor : klass.getConstructors())
{
if (arityMatches(constructor, args)) return constructor;
}
throw noSuitableConstructorException(klass, args);
}
private static boolean arityMatches(Constructor constructor, Object... args)
{
return constructor.getParameterTypes().length == args.length;
}
private static boolean typesMatch(Constructor constructor, Object[] args)
{
if (!arityMatches(constructor, args)) return false;
Class[] parameterTypes = constructor.getParameterTypes();
parameterTypes = changePrimitivesTypesToNonOnes(parameterTypes);
for (int i = 0; i < args.length; i++)
{
if (!parameterTypes[i].isInstance( args[i] )) return false;
}
return true;
}
private static Class[] changePrimitivesTypesToNonOnes(Class[] parameterTypes)
{
Class[] types = new Class[parameterTypes.length];
int cursor = 0;
for ( Class type : parameterTypes)
{
types[cursor] = getEquivalentNonPrimitiveType(type);
cursor++;
}
return types;
}
private static Class getEquivalentNonPrimitiveType(Class type)
{
if (type == null) return null;
if (type.isPrimitive())
{
Class resultType = null;
if ( type == int.class) resultType = Integer.class;
else if ( type == float.class) resultType = Float.class;
else if ( type == boolean.class) resultType = Boolean.class;
else if ( type == double.class) resultType = Double.class;
else if ( type == long.class) resultType = Long.class;
else if ( type == char.class) resultType = Character.class;
else if ( type == byte.class) resultType = Byte.class;
else if ( type == short.class) resultType = Short.class;
return resultType;
}
return type;
}
/**
* invoke.
*
* @param constructor a {@link java.lang.reflect.Constructor} object.
* @param args a {@link java.lang.Object} object.
* @param a T object.
* @return a T object.
* @throws java.lang.Throwable if any.
*/
public static T invoke( Constructor constructor, Object... args ) throws Throwable
{
try
{
return constructor.newInstance( args );
}
catch (InstantiationException e)
{
throw e.getCause();
}
}
/**
* isStatic.
*
* @param member a {@link java.lang.reflect.Member} object.
* @return a boolean.
*/
public static boolean isStatic( Member member )
{
return Modifier.isStatic( member.getModifiers() );
}
/**
* isPublic.
*
* @param member a {@link java.lang.reflect.Member} object.
* @return a boolean.
*/
public static boolean isPublic( Member member )
{
return Modifier.isPublic( member.getModifiers() );
}
private static String toString( Object... args )
{
if (args.length == 0) return "";
return "[" + CollectionUtil.joinAsString( args, ", " ) + "]";
}
private ClassUtils()
{
}
}