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package com.sun.faces.context;
import com.sun.faces.RIConstants;
import com.sun.faces.application.ApplicationAssociate;
import com.sun.faces.application.ApplicationStateInfo;
import com.sun.faces.util.ComponentStruct;
import javax.faces.component.UIComponent;
import javax.faces.component.UIViewRoot;
import javax.faces.context.FacesContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.PostAddToViewEvent;
import javax.faces.event.PreRemoveFromViewEvent;
import javax.faces.event.SystemEvent;
import javax.faces.event.SystemEventListener;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
/**
* Context for dealing with partial state saving mechanics.
*/
public class StateContext {
private static final String KEY = StateContext.class.getName() + "_KEY";
private static final String DYNAMIC_COMPONENT =
StateContext.class.getName() + "_DYNAMIC_COMPONENT";
private static final String HAS_ONE_OR_MORE_DYNAMIC_CHILD =
StateContext.class.getName() + "_HAS_ONE_OR_MORE_DYNAMIC_CHILD";
private boolean partial;
private boolean partialLocked;
private boolean trackMods = true;
private AddRemoveListener modListener;
private ApplicationStateInfo stateInfo;
private WeakReference<UIViewRoot> viewRootRef = new WeakReference<UIViewRoot>(null);
// ------------------------------------------------------------ Constructors
private StateContext(ApplicationStateInfo stateInfo) {
this.stateInfo = stateInfo;
}
// ---------------------------------------------------------- Public Methods
/**
* @param ctx the <code>FacesContext</code> for the current request
* @return <code>StateContext</code> for this request
*/
public static StateContext getStateContext(FacesContext ctx) {
StateContext stateCtx = (StateContext) ctx.getAttributes().get(KEY);
if (stateCtx == null) {
ApplicationAssociate associate = ApplicationAssociate.getCurrentInstance();
ApplicationStateInfo info = associate.getApplicationStateInfo();
stateCtx = new StateContext(info);
ctx.getAttributes().put(KEY, stateCtx);
}
return stateCtx;
}
/**
* @param current FacesContext.
* @param viewId the view ID to check or null if viewId is unknown.
* @return <code>true</code> if partial state saving should be used for the
* specified view ID, otherwise <code>false</code>
*/
public boolean partialStateSaving(FacesContext ctx, String viewId) {
// track UIViewRoot changes
UIViewRoot root = ctx.getViewRoot();
UIViewRoot refRoot = viewRootRef.get();
if (root != refRoot) {
// set weak reference to current viewRoot
this.viewRootRef = new WeakReference<UIViewRoot>(root);
// On first call in restore phase, viewRoot is null, so we treat the first
// change to not null not as a changing viewRoot.
if (refRoot != null) {
// view root changed in request processing - force usage of a
// new AddRemoveListener instance for the new viewId ...
modListener = null;
// ... and also force check for partial state saving for the new viewId
partialLocked = false;
}
}
if (!partialLocked) {
if (viewId == null) {
if (root != null) {
viewId = root.getViewId();
} else {
// View root has not yet been initialized. Check to see whether
// the target view id has been stashed away for us.
viewId = (String)ctx.getAttributes().get(RIConstants.VIEWID_KEY_NAME);
}
}
partial = stateInfo.usePartialStateSaving(viewId);
partialLocked = true;
}
return partial;
}
/**
* @return <code>true</code> if view modifications outside of the initial
* construction of the view are being tracked.
*/
public boolean trackViewModifications() {
return trackMods;
}
/**
* Installs a <code>SystemEventListener</code> on the <code>UIViewRoot</code>
* to track components added to or removed from the view.
*/
public void startTrackViewModifications() {
if (modListener == null) {
FacesContext ctx = FacesContext.getCurrentInstance();
modListener = new AddRemoveListener(ctx);
UIViewRoot root = ctx.getViewRoot();
root.subscribeToViewEvent(PostAddToViewEvent.class, modListener);
root.subscribeToViewEvent(PreRemoveFromViewEvent.class, modListener);
}
setTrackViewModifications(true);
}
/**
* Toggles the current modification tracking status.
* @param trackMods if <code>true</code> and the listener installed by
* {@link #startTrackViewModifications()} is present, then view modifications
* will be tracked. If <code>false</code>, then modification events
* will be ignored.
*/
public void setTrackViewModifications(boolean trackMods) {
this.trackMods = trackMods;
}
/**
* @param c the UIComponent to check
* @return <code>true</code> if the component was added after the initial
* view construction
*/
public boolean componentAddedDynamically(UIComponent c) {
return c.getAttributes().containsKey(DYNAMIC_COMPONENT);
}
public int getIndexOfDynamicallyAddedChildInParent(UIComponent c) {
int result = -1;
Map<String, Object> attrs = c.getAttributes();
if (attrs.containsKey(DYNAMIC_COMPONENT)) {
result = (Integer) attrs.get(DYNAMIC_COMPONENT);
}
return result;
}
public boolean hasOneOrMoreDynamicChild(UIComponent parent) {
return parent.getAttributes().containsKey(HAS_ONE_OR_MORE_DYNAMIC_CHILD);
}
private int incrementDynamicChildCount(UIComponent parent) {
int result = 0;
Map<String, Object> attrs = parent.getAttributes();
Integer cur = (Integer) attrs.get(HAS_ONE_OR_MORE_DYNAMIC_CHILD);
if (null != cur) {
result = cur++;
} else {
result = 1;
}
attrs.put(HAS_ONE_OR_MORE_DYNAMIC_CHILD, (Integer) result);
return result;
}
private int decrementDynamicChildCount(UIComponent parent) {
int result = 0;
Map<String, Object> attrs = parent.getAttributes();
Integer cur = (Integer) attrs.get(HAS_ONE_OR_MORE_DYNAMIC_CHILD);
if (null != cur) {
result = (0 < cur) ? cur-- : 0;
}
if (0 == result && null != cur){
attrs.remove(HAS_ONE_OR_MORE_DYNAMIC_CHILD);
}
return result;
}
/**
* @return a <code>Map</code> containing information about all components
* added after the initial view construction.
*/
public Map<String,ComponentStruct> getDynamicAdds() {
return ((modListener != null) ? modListener.getDynamicAdds() : null);
}
/**
* @return a <code>List</code> of client IDs that have been removed after
* the initial view construction.
*/
public List<String> getDynamicRemoves() {
return ((modListener != null) ? modListener.dynamicRemoves : null);
}
// ---------------------------------------------------------- Nested Classes
public class AddRemoveListener implements SystemEventListener {
private StateContext stateCtx;
private LinkedHashMap<String, ComponentStruct> dynamicAdds;
private List<String> dynamicRemoves;
// -------------------------------------------------------- Constructors
public AddRemoveListener(FacesContext ctx) {
stateCtx = StateContext.getStateContext(ctx);
}
// -------------------------------------------------------- Getters
public Map<String, ComponentStruct> getDynamicAdds() {
if (null == dynamicAdds) {
dynamicAdds = new LinkedHashMap<String, ComponentStruct>();
}
return dynamicAdds;
}
// ------------------------------------ Methods From SystemEventListener
public void processEvent(SystemEvent event)
throws AbortProcessingException {
FacesContext ctx = FacesContext.getCurrentInstance();
if (event instanceof PreRemoveFromViewEvent) {
if (stateCtx.trackViewModifications()) {
handleRemoveEvent(ctx, (PreRemoveFromViewEvent) event);
}
} else {
if (stateCtx.trackViewModifications()) {
handleAddEvent(ctx, (PostAddToViewEvent) event);
}
}
}
public boolean isListenerForSource(Object source) {
return (source instanceof UIComponent);
}
// ----------------------------------------------------- Private Methods
private void handleRemoveEvent(FacesContext context,
PreRemoveFromViewEvent event) {
UIComponent removed = event.getComponent();
if (removed.isTransient()) {
return;
}
if (dynamicRemoves == null) {
dynamicRemoves = new ArrayList<String>();
}
String clientId = event.getComponent().getClientId(context);
if (dynamicAdds != null && dynamicAdds.containsKey(clientId)) {
dynamicAdds.remove(clientId);
}
StateContext.this.decrementDynamicChildCount(removed.getParent());
dynamicRemoves.add(clientId);
}
private void handleAddEvent(FacesContext context,
PostAddToViewEvent event) {
// if the root is transient, then no action is ever needed here
if (context.getViewRoot().isTransient()) {
return;
}
UIComponent added = event.getComponent();
if (added.isTransient() || added instanceof UIViewRoot) {
return;
}
// this component, while not transient may be a child or facet
// of component that is. We'll have to search the parent hierarchy
// to the root to confirm.
UIComponent parent = added.getParent();
while (parent != null) {
if (parent.isTransient()) {
return;
}
parent = parent.getParent();
}
parent = added.getParent();
StateContext.this.incrementDynamicChildCount(parent);
ComponentStruct toAdd = new ComponentStruct();
toAdd.absorbComponent(context, added);
if (dynamicRemoves != null) {
dynamicRemoves.remove(toAdd.clientId);
}
added.getAttributes().put(DYNAMIC_COMPONENT, new Integer(toAdd.indexOfChildInParent));
getDynamicAdds().put(toAdd.clientId, toAdd);
}
} // END AddRemoveListener
} // END StateContext