nl.nn.xmldecoder.finder.ConstructorFinder Maven / Gradle / Ivy
/*
* Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package nl.nn.xmldecoder.finder;
import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;
/**
* This utility class provides {@code static} methods
* to find a public constructor with specified parameter types
* in specified class.
*
* @since 1.7
*
* @author Sergey A. Malenkov
*/
public final class ConstructorFinder extends AbstractFinder> {
private static final WeakCache> CACHE = new WeakCache>();
/**
* Finds public constructor
* that is declared in public class.
*
* @param type the class that can have constructor
* @param args parameter types that is used to find constructor
* @return object that represents found constructor
* @throws NoSuchMethodException if constructor could not be found
* or some constructors are found
*/
public static Constructor findConstructor(Class type, Class...args) throws NoSuchMethodException {
if (type.isPrimitive()) {
throw new NoSuchMethodException("Primitive wrapper does not contain constructors");
}
if (type.isInterface()) {
throw new NoSuchMethodException("Interface does not contain constructors");
}
if (Modifier.isAbstract(type.getModifiers())) {
throw new NoSuchMethodException("Abstract class cannot be instantiated");
}
if (!Modifier.isPublic(type.getModifiers())) {
throw new NoSuchMethodException("Class is not accessible");
}
PrimitiveWrapperMap.replacePrimitivesWithWrappers(args);
Signature signature = new Signature(type, args);
Constructor constructor = CACHE.get(signature);
if (constructor != null) {
return constructor;
}
constructor = new ConstructorFinder(args).find(type.getConstructors());
CACHE.put(signature, constructor);
return constructor;
}
/**
* Creates constructor finder with specified array of parameter types.
*
* @param args the array of parameter types
*/
private ConstructorFinder(Class[] args) {
super(args);
}
/**
* Returns an array of {@code Class} objects
* that represent the formal parameter types of the constructor
* Returns an empty array if the constructor takes no parameters.
*
* @param constructor the object that represents constructor
* @return the parameter types of the constructor
*/
@Override
protected Class[] getParameters(Constructor constructor) {
return constructor.getParameterTypes();
}
/**
* Returns {@code true} if and only if the constructor
* was declared to take a variable number of arguments.
*
* @param constructor the object that represents constructor
* @return {@code true} if the constructor was declared
* to take a variable number of arguments;
* {@code false} otherwise
*/
@Override
protected boolean isVarArgs(Constructor constructor) {
return constructor.isVarArgs();
}
/**
* Checks validness of the constructor.
* The valid constructor should be public.
*
* @param constructor the object that represents constructor
* @return {@code true} if the constructor is valid,
* {@code false} otherwise
*/
@Override
protected boolean isValid(Constructor constructor) {
return Modifier.isPublic(constructor.getModifiers());
}
}