/*

 * 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.functors;

import java.io.Serializable;

import org.apache.commons.collections4.Transformer;

/**

 * Transformer implementation that returns the result of calling

 * <code>String.valueOf</code> on the input object.

 *

 * @since 3.0

 */

public final class StringValueTransformer<T> implements Transformer<T, String>, Serializable {

    /** Serial version UID */

    private static final long serialVersionUID = 7511110693171758606L;

    /** Singleton predicate instance */

    private static final Transformer<Object, String> INSTANCE = new StringValueTransformer<>();

    /**

     * Factory returning the singleton instance.

     *

     * @param <T>  the input type

     * @return the singleton instance

     * @since 3.1

     */

    @SuppressWarnings("unchecked")

    public static <T> Transformer<T, String> stringValueTransformer() {

        return (Transformer<T, String>) INSTANCE;

    }

    /**

     * Restricted constructor.

     */

    private StringValueTransformer() {

        super();

    }

    /**

     * Transforms the input to result by calling <code>String.valueOf</code>.

     *

     * @param input  the input object to transform

     * @return the transformed result

     */

    @Override

    public String transform(final T input) {

        return String.valueOf(input);

    }

    private Object readResolve() {

        return INSTANCE;

    }

}