| /* |
| * 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.StringWriter; |
| import java.io.Writer; |
| import java.util.Locale; |
| |
| import org.apache.commons.lang3.Validate; |
| |
| /** |
| * An API for translating text. |
| * Its core use is to escape and unescape text. Because escaping and unescaping |
| * is completely contextual, the API does not present two separate signatures. |
| * |
| * @since 1.0 |
| */ |
| public abstract class CharSequenceTranslator { |
| |
| /** |
| * Array containing the hexadecimal alphabet. |
| */ |
| static final char[] HEX_DIGITS = new char[] {'0', '1', '2', '3', |
| '4', '5', '6', '7', |
| '8', '9', 'A', 'B', |
| 'C', 'D', 'E', 'F'}; |
| |
| /** |
| * Translate a set of codepoints, represented by an int index into a CharSequence, |
| * into another set of codepoints. The number of codepoints consumed must be returned, |
| * and the only IOExceptions thrown must be from interacting with the Writer so that |
| * the top level API may reliably ignore StringWriter IOExceptions. |
| * |
| * @param input CharSequence that is being translated |
| * @param index int representing the current point of translation |
| * @param out Writer to translate the text to |
| * @return int count of codepoints consumed |
| * @throws IOException if and only if the Writer produces an IOException |
| */ |
| public abstract int translate(CharSequence input, int index, Writer out) throws IOException; |
| |
| /** |
| * Helper for non-Writer usage. |
| * @param input CharSequence to be translated |
| * @return String output of translation |
| */ |
| public final String translate(final CharSequence input) { |
| if (input == null) { |
| return null; |
| } |
| try { |
| final StringWriter writer = new StringWriter(input.length() * 2); |
| translate(input, writer); |
| return writer.toString(); |
| } catch (final IOException ioe) { |
| // this should never ever happen while writing to a StringWriter |
| throw new RuntimeException(ioe); |
| } |
| } |
| |
| /** |
| * Translate an input onto a Writer. This is intentionally final as its algorithm is |
| * tightly coupled with the abstract method of this class. |
| * |
| * @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 |
| */ |
| public final void translate(final CharSequence input, final Writer out) throws IOException { |
| Validate.isTrue(out != null, "The Writer must not be null"); |
| if (input == null) { |
| return; |
| } |
| int pos = 0; |
| final int len = input.length(); |
| while (pos < len) { |
| final int consumed = translate(input, pos, out); |
| if (consumed == 0) { |
| // inlined implementation of Character.toChars(Character.codePointAt(input, pos)) |
| // avoids allocating temp char arrays and duplicate checks |
| final char c1 = input.charAt(pos); |
| out.write(c1); |
| pos++; |
| if (Character.isHighSurrogate(c1) && pos < len) { |
| final char c2 = input.charAt(pos); |
| if (Character.isLowSurrogate(c2)) { |
| out.write(c2); |
| pos++; |
| } |
| } |
| continue; |
| } |
| // contract with translators is that they have to understand codepoints |
| // and they just took care of a surrogate pair |
| for (int pt = 0; pt < consumed; pt++) { |
| pos += Character.charCount(Character.codePointAt(input, pos)); |
| } |
| } |
| } |
| |
| /** |
| * Helper method to create a merger of this translator with another set of |
| * translators. Useful in customizing the standard functionality. |
| * |
| * @param translators CharSequenceTranslator array of translators to merge with this one |
| * @return CharSequenceTranslator merging this translator with the others |
| */ |
| public final CharSequenceTranslator with(final CharSequenceTranslator... translators) { |
| final CharSequenceTranslator[] newArray = new CharSequenceTranslator[translators.length + 1]; |
| newArray[0] = this; |
| System.arraycopy(translators, 0, newArray, 1, translators.length); |
| return new AggregateTranslator(newArray); |
| } |
| |
| /** |
| * <p>Returns an upper case hexadecimal <code>String</code> for the given |
| * character.</p> |
| * |
| * @param codepoint The codepoint to convert. |
| * @return An upper case hexadecimal <code>String</code> |
| */ |
| public static String hex(final int codepoint) { |
| return Integer.toHexString(codepoint).toUpperCase(Locale.ENGLISH); |
| } |
| |
| } |