1 /*
   2  * Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.xml.bind.annotation.adapters;
  27 
  28 
  29 
  30 /**
  31  * Built-in {@link XmlAdapter} to handle <tt>xs:token</tt> and its derived types.
  32  *
  33  * <p>
  34  * This adapter removes leading and trailing whitespaces, then truncate any
  35  * sequnce of tab, CR, LF, and SP by a single whitespace character ' '.
  36  *
  37  * @author Kohsuke Kawaguchi
  38  * @since JAXB 2.0
  39  */
  40 public class CollapsedStringAdapter extends XmlAdapter<String,String> {
  41     /**
  42      * Removes leading and trailing whitespaces of the string
  43      * given as the parameter, then truncate any
  44      * sequnce of tab, CR, LF, and SP by a single whitespace character ' '.
  45      */
  46     public String unmarshal(String text) {
  47         if(text==null)  return null;        // be defensive
  48 
  49         int len = text.length();
  50 
  51         // most of the texts are already in the collapsed form.
  52         // so look for the first whitespace in the hope that we will
  53         // never see it.
  54         int s=0;
  55         while(s<len) {
  56             if(isWhiteSpace(text.charAt(s)))
  57                 break;
  58             s++;
  59         }
  60         if(s==len)
  61             // the input happens to be already collapsed.
  62             return text;
  63 
  64         // we now know that the input contains spaces.
  65         // let's sit down and do the collapsing normally.
  66 
  67         StringBuilder result = new StringBuilder(len /*allocate enough size to avoid re-allocation*/ );
  68 
  69         if(s!=0) {
  70             for( int i=0; i<s; i++ )
  71                 result.append(text.charAt(i));
  72             result.append(' ');
  73         }
  74 
  75         boolean inStripMode = true;
  76         for (int i = s+1; i < len; i++) {
  77             char ch = text.charAt(i);
  78             boolean b = isWhiteSpace(ch);
  79             if (inStripMode && b)
  80                 continue; // skip this character
  81 
  82             inStripMode = b;
  83             if (inStripMode)
  84                 result.append(' ');
  85             else
  86                 result.append(ch);
  87         }
  88 
  89         // remove trailing whitespaces
  90         len = result.length();
  91         if (len > 0 && result.charAt(len - 1) == ' ')
  92             result.setLength(len - 1);
  93         // whitespaces are already collapsed,
  94         // so all we have to do is to remove the last one character
  95         // if it's a whitespace.
  96 
  97         return result.toString();
  98     }
  99 
 100     /**
 101      * No-op.
 102      *
 103      * Just return the same string given as the parameter.
 104      */
 105     public String marshal(String s) {
 106         return s;
 107     }
 108 
 109 
 110     /** returns true if the specified char is a white space character. */
 111     protected static boolean isWhiteSpace(char ch) {
 112         // most of the characters are non-control characters.
 113         // so check that first to quickly return false for most of the cases.
 114         if( ch>0x20 )   return false;
 115 
 116         // other than we have to do four comparisons.
 117         return ch == 0x9 || ch == 0xA || ch == 0xD || ch == 0x20;
 118     }
 119 }