/*
 * 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.lang3;

import java.nio.charset.Charset;
import java.nio.charset.UnsupportedCharsetException;

/**
 * Internal use only.
 * <p>
 * Provides utilities for {@link Charset}.
 * </p>
 * <p>
 * Package private since Apache Commons IO already provides a Charsets because {@link Charset} is in
 * {@code java.nio.charset}.
 * </p>
 *
 * @since 3.10
 */
final class Charsets {

    /**
     * Returns the given {@code charset} or the default Charset if {@code charset} is null.
     *
     * @param charset a Charset or null.
     * @return the given {@code charset} or the default Charset if {@code charset} is null.
     */
    static Charset toCharset(final Charset charset) {
        return charset == null ? Charset.defaultCharset() : charset;
    }

    /**
     * Returns the given {@code charset} or the default Charset if {@code charset} is null.
     *
     * @param charsetName a Charset or null.
     * @return the given {@code charset} or the default Charset if {@code charset} is null.
     * @throws UnsupportedCharsetException If no support for the named charset is available in this instance of the Java
     *                                     virtual machine
     */
    static Charset toCharset(final String charsetName) {
        return charsetName == null ? Charset.defaultCharset() : Charset.forName(charsetName);
    }

    /**
     * Returns the given {@code charset} or the default Charset if {@code charset} is null.
     *
     * @param charsetName a Charset or null.
     * @return the given {@code charset} or the default Charset if {@code charset} is null.
     */
    static String toCharsetName(final String charsetName) {
        return charsetName == null ? Charset.defaultCharset().name() : charsetName;
    }

}
