entities.java

利用SyncML开发客户端程序的中间件

/*
 * Copyright (C) 2003-2007 Funambol
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
package com.funambol.util;

import java.util.Hashtable;

/**
 * This class supplies some methods
 * to escape / unescape special chars according XML specifications
 *
 */
class Entities {

    private static final String[][] BASIC_ARRAY = {
        {"quot" , "34"}, // " - double-quote
        {"amp"  , "38"}, // & - ampersand
        {"lt"   , "60"}, // < - less-than
        {"gt"   , "62"}, // > - greater-than
        {"apos" , "39"}, // XML apostrophe
    };

    /**
     * <p>The set of entities supported by standard XML.</p>
     */
    public static final Entities XML;

    static {
        XML = new Entities();
        XML.addEntities(BASIC_ARRAY);
    }


    static interface EntityMap {
        void add(String name, int value);

        String name(int value);

        int value(String name);
    }

    static class PrimitiveEntityMap implements EntityMap {
        private Hashtable mapNameToValue = new Hashtable();
        private Hashtable mapValueToName = new Hashtable();

        public void add(String name, int value) {
            mapNameToValue.put(name, new Integer(value));
            mapValueToName.put(new Integer(value), name);
        }

        public String name(int value) {
            return (String) mapValueToName.get(new Integer(value));
        }

        public int value(String name) {
            Object value = mapNameToValue.get(name);
            if (value == null) {
                return -1;
            }
            return ((Integer) value).intValue();
        }
    }

    static class LookupEntityMap extends PrimitiveEntityMap {

        private String[] lookupTable;
        private int      LOOKUP_TABLE_SIZE = 256;

        public String name(int value) {

            if (value < LOOKUP_TABLE_SIZE) {
                return lookupTable()[value];
            }

            return super.name(value);
        }

        private String[] lookupTable() {
            if (lookupTable == null) {
                createLookupTable();
            }
            return lookupTable;
        }

        private void createLookupTable() {
            lookupTable = new String[LOOKUP_TABLE_SIZE];
            for (int i = 0, l = LOOKUP_TABLE_SIZE; i < l; ++i) {
                lookupTable[i] = super.name(i);
            }
        }
    }

    EntityMap map = new Entities.LookupEntityMap();

    public void addEntities(String[][] entityArray) {
        for (int i = 0; i < entityArray.length; ++i) {
            addEntity(entityArray[i][0], Integer.parseInt(entityArray[i][1]));
        }
    }

    public void addEntity(String name, int value) {
        map.add(name, value);
    }

    public String entityName(int value) {
        return map.name(value);
    }


    public int entityValue(String name) {
        return map.value(name);
    }

    /**
     * <p>Escapes special characters in a <code>String</code>.</p>
     *
     *
     * @param str The <code>String</code> to escape.
     * @return A escaped <code>String</code>.
     */
    public String escape(String str) {

        char          ch          = ' '  ;

        String        entityName  = null ;
        StringBuffer  buf         = null ;

        int           intValue    = 0    ;

        buf = new StringBuffer(str.length() * 2);

        for (int i = 0, l = str.length(); i < l; ++i) {

            ch = str.charAt(i);
            entityName = this.entityName(ch);

            if (entityName == null) {

                if (ch > 0x7F) {

                    intValue = ch;
                    buf.append("&#");
                    buf.append(intValue);
                    buf.append(';');

                } else {
                    buf.append(ch);
                }
            } else {

                buf.append('&');
                buf.append(entityName);
                buf.append(';');

            }
        }

        return buf.toString();
    }

    /**
     * <p>Unescapes special characters in a <code>String</code>.</p>
     *
     * @param str The <code>String</code> to escape.
     * @return A un-escaped <code>String</code>.
     */
    public String unescape(String str) {

        StringBuffer  buf          = null ;
        String        entityName   = null ;

        char          ch           = ' '  ;
        char          charAt1      = ' '  ;

        int           entityValue  = 0    ;

        buf = new StringBuffer(str.length());

        for (int i = 0, l = str.length(); i < l; ++i) {

            ch = str.charAt(i);

            if (ch == '&') {

                int semi = str.indexOf(';', i + 1);

                if (semi == -1) {
                    buf.append(ch);
                    continue;
                }

                entityName = str.substring(i + 1, semi);

                if (entityName.charAt(0) == '#') {
                    charAt1 = entityName.charAt(1);
                    if (charAt1 == 'x' || charAt1=='X') {
                        entityValue = Integer.valueOf(entityName.substring(2), 16).intValue();
                    } else {
                        entityValue = Integer.parseInt(entityName.substring(1));
                    }
                } else {
                    entityValue = this.entityValue(entityName);
                } if (entityValue == -1) {
                    buf.append('&');
                    buf.append(entityName);
                    buf.append(';');
                } else {
                    buf.append((char) (entityValue));
                }

                i = semi;

            } else {

                buf.append(ch);

            }
        }

        return buf.toString();
    }

}