cdmlib-services/src/main/java/eu/etaxonomy/cdm/api/service/AbstractStringComparator.java

   1 // $Id$
   2 /**
   3  * Copyright (C) 2009 EDIT
   4  * European Distributed Institute of Taxonomy
   5  * http://www.e-taxonomy.eu
   6  *
   7  * The contents of this file are subject to the Mozilla Public License Version 1.1
   8  * See LICENSE.TXT at the top of this package for the full license terms.
   9  */
  10 package eu.etaxonomy.cdm.api.service;
  11
  12 import java.util.Comparator;
  13 import java.util.HashMap;
  14 import java.util.Map;
  15 import java.util.regex.Matcher;
  16 import java.util.regex.Pattern;
  17
  18 import org.springframework.stereotype.Component;
  19
  20 import eu.etaxonomy.cdm.model.taxon.TaxonNode;
  21
  22 /**
  23  * Abstract Comparator for Strings which allows define substitution rules which
  24  * are applied to the String to be compared before the actual comparison takes
  25  * place. By this it is e.g. possible to influence the position of objects in sorted lists etc.
  26  * <p>
  27  * <b>Intended usage</b>: To allow maximum flexibility the property
  28  * {@link #setSubstitutionRules(Map)} should be set in the spring application
  29  * context.
  30  *
  31  * @author a.kohlbecker
  32  * @date 24.06.2009
  33  */
  34 @Component
  35 public abstract class AbstractStringComparator implements Comparator<TaxonNode> {
  36
  37         protected Map<Pattern, String> substitutionRules = null;
  38
  39         /**
  40          * Set the private field substitutionRules. The substitutionRules consist of
  41          * a regular expression as key and a string to be prepended as value.
  42          *
  43          * @param rules
  44          */
  45         public void setSubstitutionRules(Map<String, String> substitutionRules) {
  46                 this.substitutionRules = new HashMap<Pattern, String>(substitutionRules.size());
  47                 for (String regex : substitutionRules.keySet()) {
  48                         this.substitutionRules.put(Pattern.compile(regex), substitutionRules.get(regex));
  49                 }
  50
  51         }
  52
  53         /**
  54          * Applies the first matching <code>substitutionRules</code> set by
  55          * {@link #setSubstitutionRules()} to the given String. A rules is applied
  56          * in the following way: If the regular expression matches the given string
  57          * <code>s</code> the String mapped by the regular expression is prepended
  58          * to <code>s</code>.
  59          *
  60          * @param s
  61          * @return
  62          */
  63         protected String applySubstitutionRules(String s) {
  64                 if (substitutionRules == null) {
  65                         return s;
  66                 }
  67                 StringBuffer sb = new StringBuffer();
  68                 for (Pattern pattern : substitutionRules.keySet()) {
  69                         if (pattern.matcher(s).matches()) {
  70                                 sb.append(substitutionRules.get(pattern)).append(s);
  71                                 return sb.toString();
  72                         }
  73
  74                 }
  75                 return s;
  76         }
  77
  78 }