    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.lang3.text.translate;
    018
    019import java.io.IOException;
    020import java.io.StringWriter;
    021import java.io.UncheckedIOException;
    022import java.io.Writer;
    023import java.util.Locale;
    024import java.util.Objects;
    025
    026/**
    027 * An API for translating text.
    028 * Its core use is to escape and unescape text. Because escaping and unescaping
    029 * is completely contextual, the API does not present two separate signatures.
    030 *
    031 * @since 3.0
    032 * @deprecated As of 3.6, use Apache Commons Text
    033 * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/translate/CharSequenceTranslator.html">
    034 * CharSequenceTranslator</a> instead
    035 */
    036@Deprecated
    037public abstract class CharSequenceTranslator {
    038
    039    static final char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
    040
    041    /**
    042     * Translate a set of code points, represented by an int index into a CharSequence,
    043     * into another set of code points. The number of code points consumed must be returned,
    044     * and the only IOExceptions thrown must be from interacting with the Writer so that
    045     * the top level API may reliably ignore StringWriter IOExceptions.
    046     *
    047     * @param input CharSequence that is being translated
    048     * @param index int representing the current point of translation
    049     * @param out Writer to translate the text to
    050     * @return int count of code points consumed
    051     * @throws IOException if and only if the Writer produces an IOException
    052     */
    053    public abstract int translate(CharSequence input, int index, Writer out) throws IOException;
    054
    055    /**
    056     * Helper for non-Writer usage.
    057     * @param input CharSequence to be translated
    058     * @return String output of translation
    059     */
    060    public final String translate(final CharSequence input) {
    061        if (input == null) {
    062            return null;
    063        }
    064        try {
    065            final StringWriter writer = new StringWriter(input.length() * 2);
    066            translate(input, writer);
    067            return writer.toString();
    068        } catch (final IOException ioe) {
    069            // this should never ever happen while writing to a StringWriter
    070            throw new UncheckedIOException(ioe);
    071        }
    072    }
    073
    074    /**
    075     * Translate an input onto a Writer. This is intentionally final as its algorithm is
    076     * tightly coupled with the abstract method of this class.
    077     *
    078     * @param input CharSequence that is being translated
    079     * @param writer Writer to translate the text to
    080     * @throws IOException if and only if the Writer produces an IOException
    081     */
    082    public final void translate(final CharSequence input, final Writer writer) throws IOException {
    083        Objects.requireNonNull(writer, "writer");
    084        if (input == null) {
    085            return;
    086        }
    087        int pos = 0;
    088        final int len = input.length();
    089        while (pos < len) {
    090            final int consumed = translate(input, pos, writer);
    091            if (consumed == 0) {
    092                // inlined implementation of Character.toChars(Character.codePointAt(input, pos))
    093                // avoids allocating temp char arrays and duplicate checks
    094                final char c1 = input.charAt(pos);
    095                writer.write(c1);
    096                pos++;
    097                if (Character.isHighSurrogate(c1) && pos < len) {
    098                    final char c2 = input.charAt(pos);
    099                    if (Character.isLowSurrogate(c2)) {
    100                      writer.write(c2);
    101                      pos++;
    102                    }
    103                }
    104                continue;
    105            }
    106            // contract with translators is that they have to understand code points
    107            // and they just took care of a surrogate pair
    108            for (int pt = 0; pt < consumed; pt++) {
    109                pos += Character.charCount(Character.codePointAt(input, pos));
    110            }
    111        }
    112    }
    113
    114    /**
    115     * Helper method to create a merger of this translator with another set of
    116     * translators. Useful in customizing the standard functionality.
    117     *
    118     * @param translators CharSequenceTranslator array of translators to merge with this one
    119     * @return CharSequenceTranslator merging this translator with the others
    120     */
    121    public final CharSequenceTranslator with(final CharSequenceTranslator... translators) {
    122        final CharSequenceTranslator[] newArray = new CharSequenceTranslator[translators.length + 1];
    123        newArray[0] = this;
    124        System.arraycopy(translators, 0, newArray, 1, translators.length);
    125        return new AggregateTranslator(newArray);
    126    }
    127
    128    /**
    129     * Returns an upper case hexadecimal {@link String} for the given
    130     * character.
    131     *
    132     * @param codePoint The code point to convert.
    133     * @return An upper case hexadecimal {@link String}
    134     */
    135    public static String hex(final int codePoint) {
    136        return Integer.toHexString(codePoint).toUpperCase(Locale.ENGLISH);
    137    }
    138
    139}