Eclipse Platform
Release 3.6

org.eclipse.ui.handlers
Class RadioState

java.lang.Object
  extended by org.eclipse.core.commands.common.EventManager
      extended by org.eclipse.core.commands.State
          extended by org.eclipse.jface.commands.PersistentState
              extended by org.eclipse.ui.handlers.RadioState
All Implemented Interfaces:
IExecutableExtension

public final class RadioState
extends PersistentState
implements IExecutableExtension

This state supports a radio-button like command, where the value of the parameterized command is stored as state. The command must define a state using the STATE_ID id and a string commandParameter using the PARAMETER_ID id. Menu contributions supplied by org.eclipse.ui.menus can then set the PARAMETER_ID.

When parsing from the registry, this state understands two parameters: default, which is the default value for this item; and persisted, which is whether the state should be persisted between sessions. The default parameter has no default value and must be specified in one of its forms, and the persisted parameter defaults to true. If only one parameter is passed (i.e., using the class name followed by a colon), then it is assumed to be the default parameter.

Since:
3.5
See Also:
HandlerUtil.updateRadioState(org.eclipse.core.commands.Command, String), HandlerUtil.matchesRadioState(org.eclipse.core.commands.ExecutionEvent)

Field Summary
static String PARAMETER_ID
          The parameter ID for a radio state understood by the system.
static String STATE_ID
          The state ID for a radio state understood by the system.
 
Constructor Summary
RadioState()
           
 
Method Summary
 void load(IPreferenceStore store, String preferenceKey)
          Loads this state from the preference store, given the location at which to look.
 void save(IPreferenceStore store, String preferenceKey)
          Saves this state to the preference store, given the location at which to write.
 void setInitializationData(IConfigurationElement config, String propertyName, Object data)
          This method is called by the implementation of the method IConfigurationElement.createExecutableExtension on a newly constructed extension, passing it its relevant configuration information.
 void setValue(Object value)
          Sets the value for this state object.
 
Methods inherited from class org.eclipse.jface.commands.PersistentState
setShouldPersist, shouldPersist
 
Methods inherited from class org.eclipse.core.commands.State
addListener, dispose, fireStateChanged, getId, getValue, removeListener, setId
 
Methods inherited from class org.eclipse.core.commands.common.EventManager
addListenerObject, clearListeners, getListeners, isListenerAttached, removeListenerObject
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

STATE_ID

public static final String STATE_ID
The state ID for a radio state understood by the system.

See Also:
Constant Field Values

PARAMETER_ID

public static final String PARAMETER_ID
The parameter ID for a radio state understood by the system.

See Also:
Constant Field Values
Constructor Detail

RadioState

public RadioState()
Method Detail

setInitializationData

public void setInitializationData(IConfigurationElement config,
                                  String propertyName,
                                  Object data)
Description copied from interface: IExecutableExtension
This method is called by the implementation of the method IConfigurationElement.createExecutableExtension on a newly constructed extension, passing it its relevant configuration information. Most executable extensions only make use of the first two call arguments.

Regular executable extensions specify their Java implementation class name as an attribute of the configuration element for the extension. For example

     <action run="com.example.BaseAction"/>
 
In the above example, this method would be called with a reference to the <action> element (first argument), and "run" as the name of the attribute that defined this executable extension (second argument).

The last parameter is for the specific use of extension adapters and is typically not used by regular executable extensions.

There are two supported ways of associating additional adapter-specific data with the configuration in a way that is transparent to the extension point implementor:

(1) by specifying adapter data as part of the implementation class attribute value. The Java class name can be followed by a ":" separator, followed by any adapter data in string form. For example, if the extension point specifies an attribute "run" to contain the name of the extension implementation, an adapter can be configured as

     <action run="com.example.ExternalAdapter:./cmds/util.exe -opt 3"/>
 

(2) by converting the attribute used to specify the executable extension to a child element of the original configuration element, and specifying the adapter data in the form of xml markup. Using this form, the example above would become

     <action>
         <run class="com.xyz.ExternalAdapter">
             <parameter name="exec" value="./cmds/util.exe"/>
             <parameter name="opt"  value="3"/>
         </run>
     </action>
 

Form (2) will typically only be used for extension points that anticipate the majority of extensions configured into it will in fact be in the form of adapters.

In either case, the specified adapter class is instantiated using its 0-argument public constructor. The adapter data is passed as the last argument of this method. The data argument is defined as Object. It can have the following values:

Specified by:
setInitializationData in interface IExecutableExtension
Parameters:
config - the configuration element used to trigger this execution. It can be queried by the executable extension for specific configuration properties
propertyName - the name of an attribute of the configuration element used on the createExecutableExtension(String) call. This argument can be used in the cases where a single configuration element is used to define multiple executable extensions.
data - adapter data in the form of a String, a Hashtable, or null.
See Also:
IConfigurationElement.createExecutableExtension(String)

load

public void load(IPreferenceStore store,
                 String preferenceKey)
Description copied from class: PersistentState
Loads this state from the preference store, given the location at which to look. This method must be symmetric with a call to PersistentState.save(IPreferenceStore, String).

Specified by:
load in class PersistentState
Parameters:
store - The store from which to read; must not be null.
preferenceKey - The key at which the state is stored; must not be null.

save

public void save(IPreferenceStore store,
                 String preferenceKey)
Description copied from class: PersistentState
Saves this state to the preference store, given the location at which to write. This method must be symmetric with a call to PersistentState.load(IPreferenceStore, String).

Specified by:
save in class PersistentState
Parameters:
store - The store to which the state should be written; must not be null.
preferenceKey - The key at which the state should be stored; must not be null.

setValue

public void setValue(Object value)
Description copied from class: State
Sets the value for this state object.

Overrides:
setValue in class State
Parameters:
value - The value to set; may be anything.

Eclipse Platform
Release 3.6

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