* The Property is a simple data object that contains one typed
* value. This interface contains methods to inspect and modify the stored value
* and its type, and the object's read-only state.
*
* The Property also defines the events
* ReadOnlyStatusChangeEvent and ValueChangeEvent, and
* the associated listener and notifier interfaces.
*
* The Property.Viewer interface should be used to attach the
* Property to an external data source. This way the value in the data source
* can be inspected using the Property interface.
*
* The Property.editor interface should be implemented if the value
* needs to be changed through the implementing class.
*
* Implementing this functionality is optional. If the functionality is
* missing, one should declare the Property to be in read-only mode and
* throw Property.ReadOnlyException in this function.
*
getValue and
* setValue must be compatible with this type: one must be able
* to safely cast the value returned from getValue to the given
* type and pass any variable assignable to this type as an argument to
* setValue.
*
* @return type of the Property
*/
public Class getType();
/**
* Tests if the Property is in read-only mode. In read-only mode calls to
* the method setValue will throw
* ReadOnlyException and will not modify the value of the
* Property.
*
* @return true if the Property is in read-only mode,
* false if it's not
*/
public boolean isReadOnly();
/**
* Sets the Property's read-only mode to the specified status.
*
* This functionality is optional, but all properties must implement the
* isReadOnly mode query correctly.
*
* @param newStatus
* new read-only status of the Property
*/
public void setReadOnly(boolean newStatus);
/**
* A Property that is capable of handle a transaction that can end in commit
* or rollback.
*
* Note that this does not refer to e.g. database transactions but rather
* two-phase commit that allows resetting old field values on a form etc. if
* the commit of one of the properties fails after others have already been
* committed. If
*
* @param * If the value is set during a transaction the value must not replace * the original value until {@link #commit()} is called. Still, * {@link #getValue()} must return the current value set in the * transaction. Calling {@link #rollback()} while in a transaction must * rollback the value to what it was before the transaction started. *
** {@link ValueChangeEvent}s must not be emitted for internal value * changes during a transaction. If the value changes as a result of * {@link #commit()}, a {@link ValueChangeEvent} should be emitted. *
*/ public void startTransaction(); /** * Commits and ends the transaction that is in progress. ** If the value is changed as a result of this operation, a * {@link ValueChangeEvent} is emitted if such are supported. *
* This method has no effect if there is no transaction is in progress. *
* This method must never throw an exception. */ public void commit(); /** * Aborts and rolls back the transaction that is in progress. *
* The value is reset to the value before the transaction started. No * {@link ValueChangeEvent} is emitted as a result of this. *
* This method has no effect if there is no transaction is in progress. *
* This method must never throw an exception.
*/
public void rollback();
}
/**
* Exception object that signals that a requested Property
* modification failed because it's in read-only mode.
*
* @author Vaadin Ltd.
* @since 3.0
*/
@SuppressWarnings("serial")
public class ReadOnlyException extends RuntimeException {
/**
* Constructs a new ReadOnlyException without a detail
* message.
*/
public ReadOnlyException() {
}
/**
* Constructs a new ReadOnlyException with the specified
* detail message.
*
* @param msg
* the detail message
*/
public ReadOnlyException(String msg) {
super(msg);
}
}
/**
* Interface implemented by the viewer classes capable of using a Property
* as a data source.
*
* @author Vaadin Ltd.
* @since 3.0
*/
public interface Viewer extends Serializable {
/**
* Sets the Property that serves as the data source of the viewer.
*
* @param newDataSource
* the new data source Property
*/
public void setPropertyDataSource(Property newDataSource);
/**
* Gets the Property serving as the data source of the viewer.
*
* @return the Property serving as the viewers data source
*/
public Property getPropertyDataSource();
}
/**
* Interface implemented by the editor classes capable of editing the
* Property.
*
* Implementing this interface means that the Property serving as the data
* source of the editor can be modified through the editor. It does not
* restrict the editor from editing the Property internally, though if the
* Property is in a read-only mode, attempts to modify it will result in the
* ReadOnlyException being thrown.
*
Event object specifying the Property whose value has been
* changed.
*
* @author Vaadin Ltd.
* @since 3.0
*/
public interface ValueChangeEvent extends Serializable {
/**
* Retrieves the Property that has been modified.
*
* @return source Property of the event
*/
public Property getProperty();
}
/**
* The listener interface for receiving
* ValueChangeEvent objects.
*
* @author Vaadin Ltd.
* @since 3.0
*/
public interface ValueChangeListener extends Serializable {
/**
* Notifies this listener that the Property's value has changed.
*
* @param event
* value change event object
*/
public void valueChange(Property.ValueChangeEvent event);
}
/**
* The interface for adding and removing ValueChangeEvent
* listeners. If a Property wishes to allow other objects to receive
* ValueChangeEvent generated by it, it must implement this
* interface.
*
* Note : The general Java convention is not to explicitly declare that a
* class generates events, but to directly define the
* addListener and removeListener methods. That
* way the caller of these methods has no real way of finding out if the
* class really will send the events, or if it just defines the methods to
* be able to implement an interface.
*
Event object specifying the Property whose read-only
* status has been changed.
*
* @author Vaadin Ltd.
* @since 3.0
*/
public interface ReadOnlyStatusChangeEvent extends Serializable {
/**
* Property whose read-only state has changed.
*
* @return source Property of the event.
*/
public Property getProperty();
}
/**
* The listener interface for receiving
* ReadOnlyStatusChangeEvent objects.
*
* @author Vaadin Ltd.
* @since 3.0
*/
public interface ReadOnlyStatusChangeListener extends Serializable {
/**
* Notifies this listener that a Property's read-only status has
* changed.
*
* @param event
* Read-only status change event object
*/
public void readOnlyStatusChange(
Property.ReadOnlyStatusChangeEvent event);
}
/**
* The interface for adding and removing
* ReadOnlyStatusChangeEvent listeners. If a Property wishes to
* allow other objects to receive ReadOnlyStatusChangeEvent
* generated by it, it must implement this interface.
*
* Note : The general Java convention is not to explicitly declare that a
* class generates events, but to directly define the
* addListener and removeListener methods. That
* way the caller of these methods has no real way of finding out if the
* class really will send the events, or if it just defines the methods to
* be able to implement an interface.
*