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From "Gerhard Maree (JIRA)" <j...@apache.org>
Subject [jira] Created: (LANG-352) New method replace(String text, Map replaceMap) in StringUtils
Date Thu, 16 Aug 2007 08:15:31 GMT
New method replace(String text, Map replaceMap) in StringUtils
--------------------------------------------------------------

                 Key: LANG-352
                 URL: https://issues.apache.org/jira/browse/LANG-352
             Project: Commons Lang
          Issue Type: New Feature
    Affects Versions: 2.3
            Reporter: Gerhard Maree
            Priority: Minor



Hi

I have a method that I would like to contribute to the StringUtils class. I unfortunately
can't access a CVS server on the internet, so I included the method and its test in this mail.
I'd appreciate it if someone can have a look and add the source if it is acceptable. 

The method basically replaces multiple strings in a String, but is very efficient. The description
of the method is in the Javadoc.

Regards,
Gerhard
 
Here is method to add to org.apache.commons.lang.StringUtils

    /**
     * <p>Replace all occurrences of multiple strings in a string.</p>
     * 
     * <p>It is functionally equivalent to calling 
     *  replaceAll(searchString, replaceString) repeatedly on <code>text</code>

     *  for all the strings you want to replace, but much faster </p>
     *  
     * <p><code>replaceMap</code> maps search strings to replacement strings.
     * Each key in the map will be replaced by its value in <code>text</code>.
     * </p>
     * 
     * @param text String to replace strings in. May be null
     * @param replaceMap Maps search strings to replacement strings.  
     * @return string with all values replaced. <code>null</code> if 
     *          text was null
     */
    public static String replace(String text, Map replaceMap) {
      if(isEmpty(text)) {
        return text;
      }
      StringBuffer buff = new StringBuffer(text.length());
      //map each replace string and it's next position in text
      TreeMap indexMap = new TreeMap();
      //populate indexMap with it's initial values
      for (Iterator iter = replaceMap.keySet().iterator(); iter.hasNext();) {
        String key = (String) iter.next();
        if(isBlank(key)) {
          continue;
        }
        int idx = text.indexOf(key);
        if(idx >= 0) {
          indexMap.put(new Integer(idx), key);
        }
      }
      
      //if there is nothing to replace
      if(indexMap.isEmpty()) return text;
      
      int prevIdx = 0;
      while(indexMap.size() > 0) {
        Integer idxI = (Integer)indexMap.firstKey();
        int idx = idxI.intValue();
        String keyS = (String)indexMap.remove(idxI);
        buff.append(text.substring(prevIdx, idx));
        buff.append((String)replaceMap.get(keyS));
        prevIdx = idx + keyS.length();
        idx = text.indexOf(keyS, prevIdx);
        if(idx > 0) {
          indexMap.put(new Integer(idx), keyS);
        }
      }
      buff.append(text.substring(prevIdx));
      return buff.toString();
    }


Here is the test method to add to StringUtilsTest.


    public void testReplace_StringMap() {
      Map replaceMapEmpty = new HashMap();
      Map replaceMap1 = new HashMap();
      replaceMap1.put("foo", "bar");
      replaceMap1.put("boo", "far");
      Map replaceMap2 = new HashMap();
      replaceMap2.put("foo", "");
      Map replaceMap3 = new HashMap();
      replaceMap3.put("", "foo");
      
      assertEquals(null, StringUtils.replace(null,  replaceMapEmpty));
      assertEquals(null, StringUtils.replace(null, replaceMap1));

      assertEquals("", StringUtils.replace("", replaceMapEmpty));
      assertEquals("", StringUtils.replace("", replaceMap1));

      assertEquals("foo", StringUtils.replace("foo", replaceMapEmpty));
      assertEquals("bar", StringUtils.replace("foo", replaceMap1));
      assertEquals("", StringUtils.replace("foo", replaceMap2));
      assertEquals("foo", StringUtils.replace("foo", replaceMap3));
      
      assertEquals("foobar", StringUtils.replace("foobar", replaceMapEmpty));
      assertEquals("barbar", StringUtils.replace("foobar", replaceMap1));
      assertEquals("bar", StringUtils.replace("bar", replaceMap2));

      assertEquals("fobar", StringUtils.replace("fobar", replaceMap1));
      assertEquals("barobar", StringUtils.replace("fooobar", replaceMap1));
      assertEquals("barbar", StringUtils.replace("foofoo", replaceMap1));
      assertEquals("barfar", StringUtils.replace("fooboo", replaceMap1));
      assertEquals("barfarbarfar", StringUtils.replace("fooboofooboo", replaceMap1));
      assertEquals("barbarfarfar", StringUtils.replace("foofoobooboo", replaceMap1));
     }



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