Class StrLookup.SystemPropertiesStrLookup

java.lang.Object
org.apache.commons.text.StrLookup<String>
org.apache.commons.text.StrLookup.SystemPropertiesStrLookup
All Implemented Interfaces:
Function<String,String>, UnaryOperator<String>, StringLookup
Enclosing class:
StrLookup<V>
private static final class StrLookup.SystemPropertiesStrLookup extends StrLookup<String>
Lookup implementation based on system properties.
Since:
1.0

  • Constructor Details

    • SystemPropertiesStrLookup

      private SystemPropertiesStrLookup()
      Private for Spotbugs SING_SINGLETON_GETTER_NOT_SYNCHRONIZED.

  • Method Details

    • lookup

      public String lookup(String key)
      Looks up a String key to provide a String value.

      The internal implementation may use any mechanism to return the value. The simplest implementation is to use a Map. However, virtually any implementation is possible.

      For example, it would be possible to implement a lookup that used the key as a primary key, and looked up the value on demand from the database Or, a numeric based implementation could be created that treats the key as an integer, increments the value and return the result as a string - converting 1 to 2, 15 to 16 etc.

      This method always returns a String, regardless of the underlying data, by converting it as necessary. For example: 

      Map<String, Object> map = new HashMap<String, Object>();
map.put("number", Integer.valueOf(2));
assertEquals("2", StringLookupFactory.mapStringLookup(map).lookup("number"));
      This implementation directly accesses system properties.
      Parameters:
      key - the key to look up, may be null.
      Returns:
      The matching value, null if no match.