Enum DummyLookup
- java.lang.Object
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- java.lang.Enum<DummyLookup>
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- org.apache.commons.configuration2.interpol.DummyLookup
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- All Implemented Interfaces:
java.io.Serializable
,java.lang.Comparable<DummyLookup>
,Lookup
public enum DummyLookup extends java.lang.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
- Version:
- $Id: DummyLookup.java 1624601 2014-09-12 18:04:36Z oheger $
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Enum Constant Summary
Enum Constants Enum Constant Description INSTANCE
The single instance of this class.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description java.lang.Object
lookup(java.lang.String variable)
Looks up the value of the specified variable.static DummyLookup
valueOf(java.lang.String name)
Returns the enum constant of this type with the specified name.static DummyLookup[]
values()
Returns an array containing the constants of this enum type, in the order they are declared.
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Enum Constant Detail
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INSTANCE
public static final DummyLookup INSTANCE
The single instance of this class.
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Method Detail
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values
public static DummyLookup[] values()
Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:for (DummyLookup c : DummyLookup.values()) System.out.println(c);
- Returns:
- an array containing the constants of this enum type, in the order they are declared
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valueOf
public static DummyLookup valueOf(java.lang.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:
java.lang.IllegalArgumentException
- if this enum type has no constant with the specified namejava.lang.NullPointerException
- if the argument is null
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lookup
public java.lang.Object lookup(java.lang.String variable)
Looks up the value of the specified variable. This method is called byConfigurationInterpolator
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.
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