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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.collections.functors;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import org.apache.commons.collections.FunctorException;
import org.apache.commons.collections.Transformer;

/**
 *  Transformer implementation that creates a new object instance by reflection.
 *  
 *  WARNING: from v3.2.2 onwards this class will throw an
 *  {@link UnsupportedOperationException} when trying to serialize or
 *  de-serialize an instance to prevent potential remote code execution exploits.
 *  

 *  In order to re-enable serialization support for {@code InstantiateTransformer}
 *  the following system property can be used (via -Dproperty=true):
 *  
 *  org.apache.commons.collections.enableUnsafeSerialization
 *  
 *
 *  @since Commons Collections 3.0
 *  @version $Revision$ $Date$
 *
 *  @author Stephen Colebourne
 *
 * @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
 */
@Deprecated(since = "2021-04-30")
public class InstantiateTransformer implements Transformer, Serializable {

    /**
     * The serial version
     */
    private static final long serialVersionUID = 3786388740793356347L;

    /**
     * Singleton instance that uses the no arg constructor
     */
    public static final Transformer NO_ARG_INSTANCE = new InstantiateTransformer();

    /**
     * The constructor parameter types
     */
    private final Class[] iParamTypes;

    /**
     * The constructor arguments
     */
    private final Object[] iArgs;

    /**
     * Transformer method that performs validation.
     *
     * @param paramTypes  the constructor parameter types
     * @param args  the constructor arguments
     * @return an instantiate transformer
     */
    public static Transformer getInstance(Class[] paramTypes, Object[] args) {
        if (((paramTypes == null) && (args != null)) || ((paramTypes != null) && (args == null)) || ((paramTypes != null) && (args != null) && (paramTypes.length != args.length))) {
            throw new IllegalArgumentException("Parameter types must match the arguments");
        }
        if (paramTypes == null || paramTypes.length == 0) {
            return NO_ARG_INSTANCE;
        } else {
            paramTypes = (Class[]) paramTypes.clone();
            args = (Object[]) args.clone();
        }
        return new InstantiateTransformer(paramTypes, args);
    }

    /**
     * Constructor for no arg instance.
     */
    private InstantiateTransformer() {
        super();
        iParamTypes = null;
        iArgs = null;
    }

    /**
     * Constructor that performs no validation.
     * Use getInstance if you want that.
     *
     * @param paramTypes  the constructor parameter types, not cloned
     * @param args  the constructor arguments, not cloned
     */
    public InstantiateTransformer(Class[] paramTypes, Object[] args) {
        super();
        iParamTypes = paramTypes;
        iArgs = args;
    }

    /**
     * Transforms the input Class object to a result by instantiation.
     *
     * @param input  the input object to transform
     * @return the transformed result
     */
    public Object transform(Object input) {
        try {
            if (input instanceof Class == false) {
                throw new FunctorException("InstantiateTransformer: Input object was not an instanceof Class, it was a " + (input == null ? "null object" : input.getClass().getName()));
            }
            Constructor con = ((Class) input).getConstructor(iParamTypes);
            return con.newInstance(iArgs);
        } catch (NoSuchMethodException ex) {
            throw new FunctorException("InstantiateTransformer: The constructor must exist and be public ");
        } catch (InstantiationException ex) {
            throw new FunctorException("InstantiateTransformer: InstantiationException", ex);
        } catch (IllegalAccessException ex) {
            throw new FunctorException("InstantiateTransformer: Constructor must be public", ex);
        } catch (InvocationTargetException ex) {
            throw new FunctorException("InstantiateTransformer: Constructor threw an exception", ex);
        }
    }

    /**
     * Overrides the default writeObject implementation to prevent
     * serialization (see COLLECTIONS-580).
     */
    private void writeObject(ObjectOutputStream os) throws IOException {
        FunctorUtils.checkUnsafeSerialization(InstantiateTransformer.class);
        os.defaultWriteObject();
    }

    /**
     * Overrides the default readObject implementation to prevent
     * de-serialization (see COLLECTIONS-580).
     */
    private void readObject(ObjectInputStream is) throws ClassNotFoundException, IOException {
        FunctorUtils.checkUnsafeSerialization(InstantiateTransformer.class);
        is.defaultReadObject();
    }
}