org.unix4j.variable

Class DefaultVariableContext

java.lang.Object

org.unix4j.variable.DefaultVariableContext

All Implemented Interfaces:

VariableContext, VariableResolver

public class DefaultVariableContext
extends Object
implements VariableContext

Default implementation of VariableContext.

Constructor Summary

Constructors

Constructor and Description
DefaultVariableContext()

Method Summary

Modifier and Type	Method and Description
void	addVariableResolver(VariableResolver resolver) Adds a variable resolver to this variable context.
Object	getValue(String name) Returns the value currently set for the variable given by its name, or null if no such variable exists.
<V> V	getValue(String name, ValueConverter<V> converter) Returns the value of the variable given by name and converts it into the target type <V> using the given converter.
void	removeVariableResolver(VariableResolver resolver) Removes the specified variable resolver if it exists and does nothing otherwise.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DefaultVariableContext

public DefaultVariableContext()

Method Detail

addVariableResolver

public void addVariableResolver(VariableResolver resolver)

Description copied from interface: VariableContext

Adds a variable resolver to this variable context. The last recently added resolver has preference over previously added resolvers. This allows hiding of variables for instance to support different variable scopes with the same variable names.

Specified by:

addVariableResolver in interface VariableContext

Parameters:

resolver - the resolver to add

removeVariableResolver

public void removeVariableResolver(VariableResolver resolver)

Description copied from interface: VariableContext

Removes the specified variable resolver if it exists and does nothing otherwise. If this resolver exists multiple times, the most recently added object is removed.

Specified by:

removeVariableResolver in interface VariableContext

Parameters:

resolver - the resolver to remove

getValue

public Object getValue(String name)

Description copied from interface: VariableResolver

Returns the value currently set for the variable given by its name, or null if no such variable exists.

Specified by:

getValue in interface VariableResolver

Parameters:

name - the variable name

Returns:

the value of the variable, or null if the variable does not exist

getValue

public <V> V getValue(String name,
                      ValueConverter<V> converter)
               throws IllegalArgumentException

Description copied from interface: VariableContext

Returns the value of the variable given by name and converts it into the target type <V> using the given converter. Returns null if no such variable exists. An exception is thrown if the conversion fails, or which is indicated by a null value returned by the converter for a non-null input value.

Specified by:

getValue in interface VariableContext

Type Parameters:

V - the target value type

Parameters:

name - the variable name

converter - a converter suitable to convert values into the target type <V>

Returns:

the converted value, or null if the variable does not exist

Throws:

IllegalArgumentException - if the value conversion fails, that is, if the converter returns null for the non-null input value

toString

public String toString()

Overrides:

toString in class Object