Coverage Report - org.apache.commons.lang3.text.StrLookup
 
Classes in this File Line Coverage Branch Coverage Complexity
StrLookup
86%
13/15
N/A
N/A
1.571
StrLookup$MapStrLookup
100%
9/9
100%
4/4
1.571
 
 1   
 /*
 2   
  * Licensed to the Apache Software Foundation (ASF) under one or more
 3   
  * contributor license agreements.  See the NOTICE file distributed with
 4   
  * this work for additional information regarding copyright ownership.
 5   
  * The ASF licenses this file to You under the Apache License, Version 2.0
 6   
  * (the "License"); you may not use this file except in compliance with
 7   
  * the License.  You may obtain a copy of the License at
 8   
  *
 9   
  *      http://www.apache.org/licenses/LICENSE-2.0
 10   
  *
 11   
  * Unless required by applicable law or agreed to in writing, software
 12   
  * distributed under the License is distributed on an "AS IS" BASIS,
 13   
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14   
  * See the License for the specific language governing permissions and
 15   
  * limitations under the License.
 16   
  */
 17   
 package org.apache.commons.lang3.text;
 18   
 
 19   
 import java.util.Map;
 20   
 
 21   
 /**
 22   
  * Lookup a String key to a String value.
 23   
  * <p>
 24   
  * This class represents the simplest form of a string to string map.
 25   
  * It has a benefit over a map in that it can create the result on
 26   
  * demand based on the key.
 27   
  * <p>
 28   
  * This class comes complete with various factory methods.
 29   
  * If these do not suffice, you can subclass and implement your own matcher.
 30   
  * <p>
 31   
  * For example, it would be possible to implement a lookup that used the
 32   
  * key as a primary key, and looked up the value on demand from the database
 33   
  *
 34   
  * @since 2.2
 35   
  * @version $Id: StrLookup.java 1436770 2013-01-22 07:09:45Z ggregory $
 36   
  */
 37   
 public abstract class StrLookup<V> {
 38   
 
 39   
     /**
 40   
      * Lookup that always returns null.
 41   
      */
 42   
     private static final StrLookup<String> NONE_LOOKUP;
 43   
     /**
 44   
      * Lookup that uses System properties.
 45   
      */
 46   
     private static final StrLookup<String> SYSTEM_PROPERTIES_LOOKUP;
 47   
     static {
 48  1 
         NONE_LOOKUP = new MapStrLookup<String>(null);
 49  1 
         StrLookup<String> lookup = null;
 50   
         try {
 51  1 
             final Map<?, ?> propMap = System.getProperties();
 52   
             @SuppressWarnings("unchecked") // System property keys and values are always Strings
 53  1 
             final Map<String, String> properties = (Map<String, String>) propMap;
 54  1 
             lookup = new MapStrLookup<String>(properties);
 55  0 
         } catch (final SecurityException ex) {
 56  0 
             lookup = NONE_LOOKUP;
 57  1 
         }
 58  1 
         SYSTEM_PROPERTIES_LOOKUP = lookup;
 59  1 
     }
 60   
 
 61   
     //-----------------------------------------------------------------------
 62   
     /**
 63   
      * Returns a lookup which always returns null.
 64   
      *
 65   
      * @return a lookup that always returns null, not null
 66   
      */
 67   
     public static StrLookup<?> noneLookup() {
 68  3 
         return NONE_LOOKUP;
 69   
     }
 70   
 
 71   
     /**
 72   
      * Returns a lookup which uses {@link System#getProperties() System properties}
 73   
      * to lookup the key to value.
 74   
      * <p>
 75   
      * If a security manager blocked access to system properties, then null will
 76   
      * be returned from every lookup.
 77   
      * <p>
 78   
      * If a null key is used, this lookup will throw a NullPointerException.
 79   
      *
 80   
      * @return a lookup using system properties, not null
 81   
      */
 82   
     public static StrLookup<String> systemPropertiesLookup() {
 83  5 
         return SYSTEM_PROPERTIES_LOOKUP;
 84   
     }
 85   
 
 86   
     /**
 87   
      * Returns a lookup which looks up values using a map.
 88   
      * <p>
 89   
      * If the map is null, then null will be returned from every lookup.
 90   
      * The map result object is converted to a string using toString().
 91   
      *
 92   
      * @param <V> the type of the values supported by the lookup
 93   
      * @param map  the map of keys to values, may be null
 94   
      * @return a lookup using the map, not null
 95   
      */
 96   
     public static <V> StrLookup<V> mapLookup(final Map<String, V> map) {
 97  56 
         return new MapStrLookup<V>(map);
 98   
     }
 99   
 
 100   
     //-----------------------------------------------------------------------
 101   
     /**
 102   
      * Constructor.
 103   
      */
 104   
     protected StrLookup() {
 105  58 
         super();
 106  58 
     }
 107   
 
 108   
     /**
 109   
      * Looks up a String key to a String value.
 110   
      * <p>
 111   
      * The internal implementation may use any mechanism to return the value.
 112   
      * The simplest implementation is to use a Map. However, virtually any
 113   
      * implementation is possible.
 114   
      * <p>
 115   
      * For example, it would be possible to implement a lookup that used the
 116   
      * key as a primary key, and looked up the value on demand from the database
 117   
      * Or, a numeric based implementation could be created that treats the key
 118   
      * as an integer, increments the value and return the result as a string -
 119   
      * converting 1 to 2, 15 to 16 etc.
 120   
      * <p>
 121   
      * The {@link #lookup(String)} method always returns a String, regardless of
 122   
      * the underlying data, by converting it as necessary. For example:
 123   
      * <pre>
 124   
      * Map<String, Object> map = new HashMap<String, Object>();
 125   
      * map.put("number", Integer.valueOf(2));
 126   
      * assertEquals("2", StrLookup.mapLookup(map).lookup("number"));
 127   
      * </pre>
 128   
      * @param key  the key to be looked up, may be null
 129   
      * @return the matching value, null if no match
 130   
      */
 131   
     public abstract String lookup(String key);
 132   
 
 133   
     //-----------------------------------------------------------------------
 134   
     /**
 135   
      * Lookup implementation that uses a Map.
 136   
      */
 137   
     static class MapStrLookup<V> extends StrLookup<V> {
 138   
 
 139   
         /** Map keys are variable names and value. */
 140   
         private final Map<String, V> map;
 141   
 
 142   
         /**
 143   
          * Creates a new instance backed by a Map.
 144   
          *
 145   
          * @param map  the map of keys to values, may be null
 146   
          */
 147  58 
         MapStrLookup(final Map<String, V> map) {
 148  58 
             this.map = map;
 149  58 
         }
 150   
 
 151   
         /**
 152   
          * Looks up a String key to a String value using the map.
 153   
          * <p>
 154   
          * If the map is null, then null is returned.
 155   
          * The map result object is converted to a string using toString().
 156   
          *
 157   
          * @param key  the key to be looked up, may be null
 158   
          * @return the matching value, null if no match
 159   
          */
 160   
         @Override
 161   
         public String lookup(final String key) {
 162  392 
             if (map == null) {
 163  6 
                 return null;
 164   
             }
 165  386 
             final Object obj = map.get(key);
 166  385 
             if (obj == null) {
 167  69 
                 return null;
 168   
             }
 169  316 
             return obj.toString();
 170   
         }
 171   
     }
 172   
 }
Report generated by Cobertura 1.9.4.1 on 3/1/13 5:28 AM.