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Java example source code file (REUtil.java)

This example Java source code file (REUtil.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

cachesize, match, matched, option, other, parseexception, regularexpression, reutil, skips, string, stringbuffer, strips, text, unknown

The REUtil.java Java example source code

/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 *
 * Licensed 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 com.sun.org.apache.xerces.internal.impl.xpath.regex;

import java.text.CharacterIterator;

/**
 * @xerces.internal
 *
 */
public final class REUtil {
    private REUtil() {
    }

    static final int composeFromSurrogates(int high, int low) {
        return 0x10000 + ((high-0xd800)<<10) + low-0xdc00;
    }

    static final boolean isLowSurrogate(int ch) {
        return (ch & 0xfc00) == 0xdc00;
    }

    static final boolean isHighSurrogate(int ch) {
        return (ch & 0xfc00) == 0xd800;
    }

    static final String decomposeToSurrogates(int ch) {
        char[] chs = new char[2];
        ch -= 0x10000;
        chs[0] = (char)((ch>>10)+0xd800);
        chs[1] = (char)((ch&0x3ff)+0xdc00);
        return new String(chs);
    }

    static final String substring(CharacterIterator iterator, int begin, int end) {
        char[] src = new char[end-begin];
        for (int i = 0;  i < src.length;  i ++)
            src[i] = iterator.setIndex(i+begin);
        return new String(src);
    }

    // ================================================================

    static final int getOptionValue(int ch) {
        int ret = 0;
        switch (ch) {
          case 'i':
            ret = RegularExpression.IGNORE_CASE;
            break;
          case 'm':
            ret = RegularExpression.MULTIPLE_LINES;
            break;
          case 's':
            ret = RegularExpression.SINGLE_LINE;
            break;
          case 'x':
            ret = RegularExpression.EXTENDED_COMMENT;
            break;
          case 'u':
            ret = RegularExpression.USE_UNICODE_CATEGORY;
            break;
          case 'w':
            ret = RegularExpression.UNICODE_WORD_BOUNDARY;
            break;
          case 'F':
            ret = RegularExpression.PROHIBIT_FIXED_STRING_OPTIMIZATION;
            break;
          case 'H':
            ret = RegularExpression.PROHIBIT_HEAD_CHARACTER_OPTIMIZATION;
            break;
          case 'X':
            ret = RegularExpression.XMLSCHEMA_MODE;
            break;
          case ',':
            ret = RegularExpression.SPECIAL_COMMA;
            break;
          default:
        }
        return ret;
    }

    static final int parseOptions(String opts) throws ParseException {
        if (opts == null)  return 0;
        int options = 0;
        for (int i = 0;  i < opts.length();  i ++) {
            int v = getOptionValue(opts.charAt(i));
            if (v == 0)
                throw new ParseException("Unknown Option: "+opts.substring(i), -1);
            options |= v;
        }
        return options;
    }

    static final String createOptionString(int options) {
        StringBuffer sb = new StringBuffer(9);
        if ((options & RegularExpression.PROHIBIT_FIXED_STRING_OPTIMIZATION) != 0)
            sb.append((char)'F');
        if ((options & RegularExpression.PROHIBIT_HEAD_CHARACTER_OPTIMIZATION) != 0)
            sb.append((char)'H');
        if ((options & RegularExpression.XMLSCHEMA_MODE) != 0)
            sb.append((char)'X');
        if ((options & RegularExpression.IGNORE_CASE) != 0)
            sb.append((char)'i');
        if ((options & RegularExpression.MULTIPLE_LINES) != 0)
            sb.append((char)'m');
        if ((options & RegularExpression.SINGLE_LINE) != 0)
            sb.append((char)'s');
        if ((options & RegularExpression.USE_UNICODE_CATEGORY) != 0)
            sb.append((char)'u');
        if ((options & RegularExpression.UNICODE_WORD_BOUNDARY) != 0)
            sb.append((char)'w');
        if ((options & RegularExpression.EXTENDED_COMMENT) != 0)
            sb.append((char)'x');
        if ((options & RegularExpression.SPECIAL_COMMA) != 0)
            sb.append((char)',');
        return sb.toString().intern();
    }

    // ================================================================

    static String stripExtendedComment(String regex) {
        int len = regex.length();
        StringBuffer buffer = new StringBuffer(len);
        int offset = 0;
        while (offset < len) {
            int ch = regex.charAt(offset++);
                                                // Skips a white space.
            if (ch == '\t' || ch == '\n' || ch == '\f' || ch == '\r' || ch == ' ')
                continue;

            if (ch == '#') {                    // Skips chracters between '#' and a line end.
                while (offset < len) {
                    ch = regex.charAt(offset++);
                    if (ch == '\r' || ch == '\n')
                        break;
                }
                continue;
            }

            int next;                           // Strips an escaped white space.
            if (ch == '\\' && offset < len) {
                if ((next = regex.charAt(offset)) == '#'
                    || next == '\t' || next == '\n' || next == '\f'
                    || next == '\r' || next == ' ') {
                    buffer.append((char)next);
                    offset ++;
                } else {                        // Other escaped character.
                    buffer.append((char)'\\');
                    buffer.append((char)next);
                    offset ++;
                }
            } else                              // As is.
                buffer.append((char)ch);
        }
        return buffer.toString();
    }

    // ================================================================

    /**
     * Sample entry.
     * <div>Usage: com.sun.org.apache.xerces.internal.utils.regex.REUtil <regex> <string>
*/ public static void main(String[] argv) { String pattern = null; try { String options = ""; String target = null; if( argv.length == 0 ) { System.out.println( "Error:Usage: java REUtil -i|-m|-s|-u|-w|-X regularExpression String" ); System.exit( 0 ); } for (int i = 0; i < argv.length; i ++) { if (argv[i].length() == 0 || argv[i].charAt(0) != '-') { if (pattern == null) pattern = argv[i]; else if (target == null) target = argv[i]; else System.err.println("Unnecessary: "+argv[i]); } else if (argv[i].equals("-i")) { options += "i"; } else if (argv[i].equals("-m")) { options += "m"; } else if (argv[i].equals("-s")) { options += "s"; } else if (argv[i].equals("-u")) { options += "u"; } else if (argv[i].equals("-w")) { options += "w"; } else if (argv[i].equals("-X")) { options += "X"; } else { System.err.println("Unknown option: "+argv[i]); } } RegularExpression reg = new RegularExpression(pattern, options); System.out.println("RegularExpression: "+reg); Match match = new Match(); reg.matches(target, match); for (int i = 0; i < match.getNumberOfGroups(); i ++) { if (i == 0 ) System.out.print("Matched range for the whole pattern: "); else System.out.print("["+i+"]: "); if (match.getBeginning(i) < 0) System.out.println("-1"); else { System.out.print(match.getBeginning(i)+", "+match.getEnd(i)+", "); System.out.println("\""+match.getCapturedText(i)+"\""); } } } catch (ParseException pe) { if (pattern == null) { pe.printStackTrace(); } else { System.err.println("com.sun.org.apache.xerces.internal.utils.regex.ParseException: "+pe.getMessage()); String indent = " "; System.err.println(indent+pattern); int loc = pe.getLocation(); if (loc >= 0) { System.err.print(indent); for (int i = 0; i < loc; i ++) System.err.print("-"); System.err.println("^"); } } } catch (Exception e) { e.printStackTrace(); } } static final int CACHESIZE = 20; static final RegularExpression[] regexCache = new RegularExpression[CACHESIZE]; /** * Creates a RegularExpression instance. * This method caches created instances. * * @see RegularExpression#RegularExpression(java.lang.String, java.lang.String) */ public static RegularExpression createRegex(String pattern, String options) throws ParseException { RegularExpression re = null; int intOptions = REUtil.parseOptions(options); synchronized (REUtil.regexCache) { int i; for (i = 0; i < REUtil.CACHESIZE; i ++) { RegularExpression cached = REUtil.regexCache[i]; if (cached == null) { i = -1; break; } if (cached.equals(pattern, intOptions)) { re = cached; break; } } if (re != null) { if (i != 0) { System.arraycopy(REUtil.regexCache, 0, REUtil.regexCache, 1, i); REUtil.regexCache[0] = re; } } else { re = new RegularExpression(pattern, options); System.arraycopy(REUtil.regexCache, 0, REUtil.regexCache, 1, REUtil.CACHESIZE-1); REUtil.regexCache[0] = re; } } return re; } /** * * @see RegularExpression#matches(java.lang.String) */ public static boolean matches(String regex, String target) throws ParseException { return REUtil.createRegex(regex, null).matches(target); } /** * * @see RegularExpression#matches(java.lang.String) */ public static boolean matches(String regex, String options, String target) throws ParseException { return REUtil.createRegex(regex, options).matches(target); } // ================================================================ /** * */ public static String quoteMeta(String literal) { int len = literal.length(); StringBuffer buffer = null; for (int i = 0; i < len; i ++) { int ch = literal.charAt(i); if (".*+?{[()|\\^$".indexOf(ch) >= 0) { if (buffer == null) { buffer = new StringBuffer(i+(len-i)*2); if (i > 0) buffer.append(literal.substring(0, i)); } buffer.append((char)'\\'); buffer.append((char)ch); } else if (buffer != null) buffer.append((char)ch); } return buffer != null ? buffer.toString() : literal; } // ================================================================ static void dumpString(String v) { for (int i = 0; i < v.length(); i ++) { System.out.print(Integer.toHexString(v.charAt(i))); System.out.print(" "); } System.out.println(); } }

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