IValueVariable (Eclipse Platform API Specification)

All Superinterfaces:

IStringVariable
```
public interface IValueVariable
extends IStringVariable
```
A variable with a value that can be set and retrieved. The context in which a value variable is referenced does not affect the value of the variable. A value variable can be contributed by an extension or created programmatically. A contributor may optionally specify an initial value for a variable, or provide a delegate that will initialize the variable with a value.
Since 3.3, a variable can be specified as a "read only" preventing users from changing the value after it has been initialized. Furthermore, a read only variable that is contributed by an extension will always load the value from the extension.

Example of a value variable contribution with an initial value, the specified variable is created with the initial value "/usr/local/foo".
```
  <extension point="org.eclipse.core.variables.valueVariables">
   <variable
    name="FOO_HOME"
    initialValue="/usr/local/foo">
   </variable>
  </extension>
 
```
Example of a value variable contribution with an initializer class, the class "com.example.FooLocator" will be used to initialize the value the first time it's requested.
```
  <extension point="org.eclipse.core.variables.valueVariables">
   <variable
    name="FOO_HOME"
    initializerClass="com.example.FooLocator">
   </variable>
  </extension>
 
```
Since:

3.0

Restriction:

This interface is not intended to be implemented by clients.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`String`	`getValue()`	Returns the value of this variable, or `null` if none.
`boolean`	`isContributed()`	Returns whether this variable was contributed by an extension.
`boolean`	`isReadOnly()`	Returns whether this variable is read only.
`void`	`setDescription(String description)`	Sets the description of this variable to the given value.
`void`	`setValue(String value)`	Sets the value of this variable to the given value.

Methods inherited from interface org.eclipse.core.variables.IStringVariable
getDescription, getName

- Method Detail
  - setValue
```
void setValue(String value)
```
    Sets the value of this variable to the given value. Since 3.3, this has no effect if this variable is read only.
    
    Parameters:
    
    value - variable value
  - getValue
```
String getValue()
```
    Returns the value of this variable, or null if none.
    
    Returns:
    
    the value of this variable, or null if none
  - isContributed
```
boolean isContributed()
```
    Returns whether this variable was contributed by an extension.
    
    Returns:
    
    whether this variable was contributed by an extension
  - isReadOnly
```
boolean isReadOnly()
```
    Returns whether this variable is read only.
    
    Returns:
    
    whether this variable is read only
    
    Since:
    
    3.3
  - setDescription
```
void setDescription(String description)
```
    Sets the description of this variable to the given value.
    
    Parameters:
    
    description - variable description, possibly null