* Loads a subclass of an ACSObject from the database. * By default, uses a BigDecimal state parameter in order to * store and retrieve the item ID. * *
The getSelectedKey(PageState state) method will
* return the BigDecimal ID of the currently selected object. This
* method will return the ID even if the object with this ID does not
* actually exist.
The getSelectedObject(PageState state) method will
* return the object whose ID is getSelectedKey(PageState state). If
* the object does not actually exist, the method will return
* null.
Thus, it is possible to implement the following pattern:
* ** *ACSObjectSelectionModel model = new ACSObjectSelectionModel(....); * // .... * ACSObject obj; * if(model.isSelected(state)) { * obj = (ACSObject) model.getSelectedObject(state); * if (obj == null) { * // Create a new object * obj = model.createObject(model.getSelectedKey(state)); * model.setSelectedObject(state, obj); * } * }
The createObject method is merely a convenience
* method for instantiating the right subclass of
* ACSObject.
Advanced Usage: The ACSObjectSelectionModel
* is actually just a wrapper for a {@link SingleSelectionModel} which
* maintains the currently selected object's ID as a {@link
* BigDecimal}. By default, a new {@link
* ParameterSingleSelectionModel} is wrapped in this way; however, any
* {@link SingleSelectionModel} may be wrapped. Thus, it becomes
* possible to use the ACSObjectSelectionModel even if
* the currently selected ID is not stored in a state parameter.
ACSObjectSelectionModel
*
* @param javaClass The name of the Java class which represents
* the object. Must be a subclass of {@link ACSObject}. In
* addition, the class must have a constructor with a single
* {@link OID} parameter.
* @param objectType The name of the persistence metadata object type
* which represents the ACS object. In practice, will often be
* the same as the javaClass.
* @param parameterName The name of the state parameter which will
* be used to store the object ID.
* @deprecated
*/
public ACSObjectSelectionModel(
String javaClass, String objectType, String parameterName
) {
this(javaClass, objectType, new BigDecimalParameter(parameterName));
}
/**
* Construct a new ACSObjectSelectionModel
*
* @param javaClass The name of the Java class which represents
* the object. Must be a subclass of {@link ACSObject}. In
* addition, the class must have a constructor with a single
* {@link OID} parameter.
* @param objectType The name of the persistence metadata object type
* which represents the ACS object. In practice, will often be
* the same as the javaClass.
* @param parameter The state parameter which should be used to store
* the object ID
*/
public ACSObjectSelectionModel(
String javaClass, String objectType, BigDecimalParameter parameter
) {
this(javaClass, objectType,
new ParameterSingleSelectionModel(parameter));
}
/**
* Construct a new ACSObjectSelectionModel
*
* @param javaClass The name of the Java class which represents
* the object. Must be a subclass of {@link ACSObject}. In
* addition, the class must have a constructor with a single
* {@link OID} parameter.
* @param objectType The name of the persistence metadata object type
* which represents the ACS object. In practice, will often be
* the same as the javaClass.
* @param model The {@link SingleSelectionModel} which will supply
* a {@link BigDecimal} ID of the currently selected object
* @deprecated
*/
public ACSObjectSelectionModel(
String javaClass, String objectType, SingleSelectionModel model
) {
m_object = new RequestLocal();
m_loaded = new RequestLocal() {
protected Object initialValue(PageState state) {
return Boolean.FALSE;
}
};
try {
m_javaClass = Class.forName(javaClass);
m_constructor = m_javaClass.getConstructor (
new Class[]{OID.class}
);
} catch (Exception e) {
s_log.error("Problem loading class " + javaClass, e);
throw new UncheckedWrapperException
("Problem loading class " + javaClass);
}
m_objectType = objectType;
m_model = model;
}
/**
* Set the ID of the current object
*
* @param state The page state
* @param key A {@link BigDecimal} primary key for the object,
* or a String representation of a BigDecimal, such as "42".
* @deprecated
*/
public void setSelectedKey(PageState state, Object key) {
// Support both strings and BigDecimals
BigDecimal id = null;
if(key != null) {
id = new BigDecimal(key.toString());
}
m_object.set(state, null);
m_loaded.set(state, Boolean.FALSE);
m_model.setSelectedKey(state, id);
}
/**
* Return the object which was selected and loaded from the database,
* using the values supplied in the page state. May return null
* if no object was selected, or if the item was not found.
*
* @param state The page state
* @return The item domain object, or null if no item is
* selected.
*
* @deprecated
*/
public DomainObject getSelectedObject(PageState state) {
if(! isInitialized(state)) {
m_loaded.set(state, Boolean.TRUE);
BigDecimal id = (BigDecimal)getSelectedKey(state);
if(id == null) {
return null;
}
// Load the item from the database
try {
OID oid = new OID(m_objectType, id);
ACSObject item = (ACSObject)m_constructor.newInstance(
new OID[]{oid}
);
m_object.set(state, item);
return item;
} catch (Exception ex) {
s_log.warn("ACSObject " + id + " not found.", ex);
return null;
}
} else {
return (ACSObject)m_object.get(state);
}
}
/**
* Select the specified object.
*
* @param state The page state
* @param object The content item to set
* @deprecated
*/
public void setSelectedObject(PageState state, DomainObject object) {
ACSObject item = (ACSObject)object;
m_object.set(state, item);
if(item == null) {
m_loaded.set(state, Boolean.FALSE);
m_model.setSelectedKey(state, null);
} else {
m_loaded.set(state, Boolean.TRUE);
m_model.setSelectedKey(state, item.getID());
}
//fireStateChanged(state);
}
/**
* Determine if the attempt to load the selected object has
* been made yet. Child classes may use this method to
* perform request-local initialization.
*
* @param state the page state
* @return true if the attempt to load the selected object has
* already been made, false otherwise
* @deprecated
*/
public boolean isInitialized(PageState state) {
return ((Boolean)m_loaded.get(state)).booleanValue();
}
/**
* A utility function which creates a new object with the given ID.
* Uses reflection to create the instance of the class supplied
* in the constructor to this ACSObjectSelectionModel.
*
* @param id The id of the new item
* @return The newly created item
* @post return != null
* @deprecated
*/
public ACSObject createACSObject(BigDecimal id) throws ServletException {
s_log.debug ("Creating a new object: " + id);
try {
ACSObject item = (ACSObject)m_javaClass.newInstance();
s_log.info("XXXXXXXX creating new object with id " + item.getID() + ";;; id should be " + id);
// TODO item.setID(id);
return item;
} catch (Exception e) {
s_log.error("Error creating ACSObject with id = " + id, e);
throw new ServletException(e);
}
}
/**
* @return the Class of the content items which are produced
* by this model
* @deprecated
*/
public Class getJavaClass() {
return m_javaClass;
}
/**
* @return The name of the object type of the
* content items which are produced by this model
* @deprecated
*/
public String getObjectType() {
return m_objectType;
}
/**
* @return the underlying {@link SingleSelectionModel} which
* maintains the ID of the selected object
* @deprecated
*/
public SingleSelectionModel getSingleSelectionModel() {
return m_model;
}
////////////////////////
//
// Passthrough methods
/**
* Return true if there is a selected object.
*
* @param state represents the state of the current request
* @return true if there is a selected component.
* @deprecated
*/
public boolean isSelected(PageState state) {
return m_model.isSelected(state);
}
/**
* Return the key that identifies the selected object.
*
* @param state the current page state
* @return the {@link BigDecimal} ID of the currently selected
* object, or null if no object is selected
* @deprecated
*/
public Object getSelectedKey(PageState state) {
return m_model.getSelectedKey(state);
}
/**
* Clear the selection.
*
* @param state the current page state.
* @post ! isSelected(state)
* @post ! isInitialized(state)
* @deprecated
*/
public void clearSelection(PageState state) {
m_model.clearSelection(state);
m_object.set(state, null);
m_loaded.set(state, Boolean.FALSE);
}
/**
* Add a change listener to the model. The listener's
* stateChanged is called whenever the selected key changes.
*
* @param l a listener to notify when the selected key changes
* @deprecated
*/
public void addChangeListener(ChangeListener l) {
m_model.addChangeListener(l);
}
/**
* Remove a change listener from the model.
*
* @param l the listener to remove.
* @deprecated
*/
public void removeChangeListener(ChangeListener l) {
m_model.removeChangeListener(l);
}
/**
* Return the state parameter which will be used to keep track
* of the currently selected key. Most likely, the parameter will
* be a {@link BigDecimalParameter}.
*
* @return The state parameter which should be used to keep
* track of the ID of the currently selected object, or null
* if the ID is computed in some other way
* @see SingleSelectionModel#getStateParameter()
* @deprecated
*/
public ParameterModel getStateParameter() {
return m_model.getStateParameter();
}
}