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	/*
	* 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.
	*/
	package org.apache.commons.collections4;

	import org.apache.commons.collections4.functors.ConstantFactory;
	import org.apache.commons.collections4.functors.ExceptionFactory;
	import org.apache.commons.collections4.functors.InstantiateFactory;
	import org.apache.commons.collections4.functors.PrototypeFactory;

	/**
	* <code>FactoryUtils</code> provides reference implementations and utilities
	* for the Factory functor interface. The supplied factories are:
	* <ul>
	* <li>Prototype - clones a specified object
	* <li>Instantiate - creates objects using reflection
	* <li>Constant - always returns the same object
	* <li>Null - always returns null
	* <li>Exception - always throws an exception
	* </ul>
	* <p>
	* Since v4.1 only factories which are considered to be safe are
	* Serializable. Factories considered to be unsafe for serialization are:
	* <ul>
	* <li>Prototype
	* <li>Instantiate
	* </ul>
	*
	* @since 3.0
	*/
	public class FactoryUtils {

	/**
	* This class is not normally instantiated.
	*/
	private FactoryUtils() {}

	/**
	* Gets a Factory that always throws an exception.
	* This could be useful during testing as a placeholder.
	*
	* @see org.apache.commons.collections4.functors.ExceptionFactory
	*
	* @param <T> the type that the factory creates
	* @return the factory
	*/
	public static <T> Factory<T> exceptionFactory() {
	return ExceptionFactory.<T>exceptionFactory();
	}

	/**
	* Gets a Factory that will return null each time the factory is used.
	* This could be useful during testing as a placeholder.
	*
	* @see org.apache.commons.collections4.functors.ConstantFactory
	* @param <T> the "type" of null object the factory should return.
	* @return the factory
	*/
	public static <T> Factory<T> nullFactory() {
	return ConstantFactory.<T>constantFactory(null);
	}

	/**
	* Creates a Factory that will return the same object each time the factory
	* is used. No check is made that the object is immutable. In general, only
	* immutable objects should use the constant factory. Mutable objects should
	* use the prototype factory.
	*
	* @see org.apache.commons.collections4.functors.ConstantFactory
	*
	* @param <T> the type that the factory creates
	* @param constantToReturn the constant object to return each time in the factory
	* @return the <code>constant</code> factory.
	*/
	public static <T> Factory<T> constantFactory(final T constantToReturn) {
	return ConstantFactory.constantFactory(constantToReturn);
	}

	/**
	* Creates a Factory that will return a clone of the same prototype object
	* each time the factory is used. The prototype will be cloned using one of these
	* techniques (in order):
	*
	* <ul>
	* <li>public clone method</li>
	* <li>public copy constructor</li>
	* <li>serialization clone</li>
	* </ul>
	*
	* @see org.apache.commons.collections4.functors.PrototypeFactory
	*
	* @param <T> the type that the factory creates
	* @param prototype the object to clone each time in the factory
	* @return the <code>prototype</code> factory, or a {@link ConstantFactory#NULL_INSTANCE} if
	* the {@code prototype} is {@code null}
	* @throws IllegalArgumentException if the prototype cannot be cloned
	*/
	public static <T> Factory<T> prototypeFactory(final T prototype) {
	return PrototypeFactory.<T>prototypeFactory(prototype);
	}

	/**
	* Creates a Factory that can create objects of a specific type using
	* a no-args constructor.
	*
	* @see org.apache.commons.collections4.functors.InstantiateFactory
	*
	* @param <T> the type that the factory creates
	* @param classToInstantiate the Class to instantiate each time in the factory
	* @return the <code>reflection</code> factory
	* @throws NullPointerException if the classToInstantiate is null
	*/
	public static <T> Factory<T> instantiateFactory(final Class<T> classToInstantiate) {
	return InstantiateFactory.instantiateFactory(classToInstantiate, null, null);
	}

	/**
	* Creates a Factory that can create objects of a specific type using
	* the arguments specified to this method.
	*
	* @see org.apache.commons.collections4.functors.InstantiateFactory
	*
	* @param <T> the type that the factory creates
	* @param classToInstantiate the Class to instantiate each time in the factory
	* @param paramTypes parameter types for the constructor, can be null
	* @param args the arguments to pass to the constructor, can be null
	* @return the <code>reflection</code> factory
	* @throws NullPointerException if the classToInstantiate is null
	* @throws IllegalArgumentException if the paramTypes and args don't match
	* @throws IllegalArgumentException if the constructor doesn't exist
	*/
	public static <T> Factory<T> instantiateFactory(final Class<T> classToInstantiate, final Class<?>[] paramTypes,
	final Object[] args) {
	return InstantiateFactory.instantiateFactory(classToInstantiate, paramTypes, args);
	}

	}

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