Package org.apache.commons.configuration2.interpol

Enum DummyLookup

java.lang.Object
java.lang.Enum<DummyLookup>
org.apache.commons.configuration2.interpol.DummyLookup
All Implemented Interfaces:
Serializable, Comparable<DummyLookup>, Lookup
public enum DummyLookup extends Enum<DummyLookup> implements Lookup

A simple dummy Lookup implementation.

This implementation always returns null for a passed in variable indicating that it cannot resolve that variable. This is useful for instance as an application of the null object pattern.

This class does not define any state, therefore a single instance can be shared. To enforce usage of only a single instance this class is actually an enumeration.

Since:
2.0

  • Enum Constant Details

  • Method Details

    • values

      public static DummyLookup[] values()
      Returns an array containing the constants of this enum type, in the order they are declared.
      Returns:
      an array containing the constants of this enum type, in the order they are declared

    • valueOf

      public static DummyLookup valueOf(String name)
      Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum type has no constant with the specified name
      NullPointerException - if the argument is null

    • lookup

      public Object lookup(String variable)
      Looks up the value of the specified variable. This method is called by ConfigurationInterpolator with the variable name extracted from the expression to interpolate (i.e. the prefix name has already been removed). A concrete implementation has to return the value of this variable or null if the variable name is unknown. This implementation always returns null.
      Specified by:
      lookup in interface Lookup
      Parameters:
      variable - the name of the variable to be resolved
      Returns:
      the value of this variable or null