/*

 * 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.text.translate;

import java.io.IOException;

import java.io.Writer;

/**

 * Abstract translator for processing whole input in single pass.

 * Handles initial index checking and counting of returned code points.

 */

abstract class SinglePassTranslator extends CharSequenceTranslator {

    @Override

    public int translate(final CharSequence input, final int index, final Writer out) throws IOException {

        if (index != 0) {

            throw new IllegalArgumentException(getClassName() + ".translate(final CharSequence input, final int "

                    + "index, final Writer out) can not handle a non-zero index.");

        }

        translateWhole(input, out);

        return Character.codePointCount(input, index, input.length());

    }

    /**

     * A utility method to be used in the {@link #translate(CharSequence, int, Writer)} method.

     *

     * @return The name of this or the extending class.

     */

    private String getClassName() {

        final Class<? extends SinglePassTranslator> clazz = this.getClass();

        return clazz.isAnonymousClass() ?  clazz.getName() : clazz.getSimpleName();

    }

    /**

     * Translate whole set of code points passed in input.

     *

     * @param input CharSequence that is being translated

     * @param out Writer to translate the text to

     * @throws IOException if and only if the Writer produces an IOException

     */

    abstract void translateWhole(CharSequence input, Writer out) throws IOException;

}