128 lines
4.6 KiB
Java
128 lines
4.6 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.commons.lang3.text.translate;
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import java.io.IOException;
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import java.io.StringWriter;
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import java.io.Writer;
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import java.util.Locale;
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/**
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* An API for translating text. Its core use is to escape and unescape text.
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* Because escaping and unescaping is completely contextual, the API does not
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* present two separate signatures.
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*
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* @since 3.0
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* @version $Id: CharSequenceTranslator.java 1146844 2011-07-14 18:49:51Z
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* mbenson $
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*/
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public abstract class CharSequenceTranslator {
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/**
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* Helper for non-Writer usage.
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*
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* @param input CharSequence to be translated
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* @return String output of translation
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*/
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public final String translate(final CharSequence input) {
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if (input == null) return null;
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try {
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final StringWriter writer = new StringWriter(input.length() * 2);
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translate(input, writer);
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return writer.toString();
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} catch (final IOException ioe) {
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// this should never ever happen while writing to a StringWriter
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throw new RuntimeException(ioe);
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}
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}
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/**
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* Translate a set of codepoints, represented by an int index into a
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* CharSequence, into another set of codepoints. The number of codepoints
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* consumed must be returned, and the only IOExceptions thrown must be from
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* interacting with the Writer so that the top level API may reliable ignore
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* StringWriter IOExceptions.
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*
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* @param input CharSequence that is being translated
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* @param index int representing the current point of translation
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* @param out Writer to translate the text to
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* @return int count of codepoints consumed
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* @throws IOException if and only if the Writer produces an IOException
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*/
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public abstract int translate(CharSequence input, int index, Writer out) throws IOException;
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/**
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* Translate an input onto a Writer. This is intentionally final as its
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* algorithm is tightly coupled with the abstract method of this class.
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*
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* @param input CharSequence that is being translated
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* @param out Writer to translate the text to
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* @throws IOException if and only if the Writer produces an IOException
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*/
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public final void translate(final CharSequence input, final Writer out) throws IOException {
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if (out == null) throw new IllegalArgumentException("The Writer must not be null");
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if (input == null) return;
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int pos = 0;
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final int len = input.length();
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while (pos < len) {
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final int consumed = translate(input, pos, out);
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if (consumed == 0) {
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final char[] c = Character.toChars(Character.codePointAt(input, pos));
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out.write(c);
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pos += c.length;
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continue;
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}
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// // contract with translators is that they have to understand
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// codepoints
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// // and they just took care of a surrogate pair
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for (int pt = 0; pt < consumed; pt++) {
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pos += Character.charCount(Character.codePointAt(input, pos));
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}
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}
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}
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/**
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* Helper method to create a merger of this translator with another set of
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* translators. Useful in customizing the standard functionality.
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*
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* @param translators CharSequenceTranslator array of translators to merge
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* with this one
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* @return CharSequenceTranslator merging this translator with the others
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*/
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public final CharSequenceTranslator with(final CharSequenceTranslator... translators) {
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final CharSequenceTranslator[] newArray = new CharSequenceTranslator[translators.length + 1];
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newArray[0] = this;
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System.arraycopy(translators, 0, newArray, 1, translators.length);
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return new AggregateTranslator(newArray);
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}
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/**
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* <p>
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* Returns an upper case hexadecimal <code>String</code> for the given
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* character.
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* </p>
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*
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* @param codepoint The codepoint to convert.
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* @return An upper case hexadecimal <code>String</code>
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*/
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public static String hex(final int codepoint) {
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return Integer.toHexString(codepoint).toUpperCase(Locale.ENGLISH);
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}
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}
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