ComponentResourceDelegate.java

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package com.sun.faces.facelets.tag.jsf.html;

import com.sun.faces.facelets.tag.jsf.ComponentSupport;
import com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl;

import javax.faces.component.UIComponent;
import javax.faces.component.UIViewRoot;
import javax.faces.context.FacesContext;
import javax.faces.view.facelets.ComponentHandler;
import javax.faces.view.facelets.FaceletContext;
import javax.faces.view.facelets.TagAttribute;
import javax.faces.view.facelets.TagAttributes;
import java.util.List;

import static com.sun.faces.facelets.tag.jsf.ComponentSupport.MARK_CREATED;

/**
 * This class overrides key methods from <code>ComponentTagHandlerDelegateImpl</code>
 * in order to properly find existing component resources as well as properly handling
 * the case when this concrete implementations of this class are applied more than
 * once for a particular request.
 */
public abstract class ComponentResourceDelegate extends ComponentTagHandlerDelegateImpl {

    private TagAttributes attributes;

    // ------------------------------------------------------------ Constructors


    public ComponentResourceDelegate(ComponentHandler owner) {

        super(owner);
        this.attributes = owner.getTag().getAttributes();

    }


    // ----------------------------------------- Methods from TagHandlerDelegate


    @Override
    protected UIComponent findChild(FaceletContext ctx,
                                    UIComponent parent,
                                    String tagId) {

        // If we have a target for this particular component, we need to
        // query the UIViewRoot's component resources, otherwise defer
        // to our super class.
        String target = getLocationTarget(ctx);
        if (target != null) {
            final UIViewRoot root = ctx.getFacesContext().getViewRoot();
            List<UIComponent> resources =
                  root.getComponentResources(ctx.getFacesContext(), target);
            for (UIComponent c : resources) {
                String cid = (String) c.getAttributes().get(MARK_CREATED);
                if (tagId.equals(cid)) {
                    return c;
                }
            }
            return null;
        } else {
            return super.findChild(ctx, parent, tagId);
        }

    }


    @Override protected void addComponentToView(FaceletContext ctx,
                                                UIComponent parent,
                                                UIComponent c,
                                                boolean componentFound) {

        if (!componentFound) {
            // default to the existing logic which will add the component
            // in-place.  An event will be fired to move the component
            // as a UIViewRoot component resource
            super.addComponentToView(ctx, parent, c, componentFound);
        } else {
            // when re-applying we supress events for existing components,
            // so if we simply relied on the default logic, the resources
            // wouldn't be be moved.  We'll do it manually instead.
            String target = getLocationTarget(ctx);
            if (target != null) {
                final UIViewRoot root = ctx.getFacesContext().getViewRoot();
                root.addComponentResource(ctx.getFacesContext(), c, target);
            } else {
                super.addComponentToView(ctx, parent, c, componentFound);
            }
        }

    }




    @Override
    protected void doOrphanedChildCleanup(FaceletContext ctx,
                                          UIComponent parent,
                                          UIComponent c) {

        FacesContext context = ctx.getFacesContext();
        boolean suppressEvents =
              ComponentSupport.suppressViewModificationEvents(context);
        if (suppressEvents) {
            // if the component has already been found, it will be removed
            // and added back to the view.  We don't want to publish events
            // for this case.
            context.setProcessingEvents(false);
        }

        ComponentSupport.finalizeForDeletion(c);
        UIViewRoot root = context.getViewRoot();
        root.removeComponentResource(context, c, getLocationTarget(ctx));

        if (suppressEvents) {
            // restore the original state
            context.setProcessingEvents(true);
        }

    }


    // ------------------------------------------------------- Protected Methods


    protected abstract String getLocationTarget(FaceletContext ctx);


    protected TagAttribute getAttribute(String name) {

        return attributes.get(name);

    }

}