CommandLinkRenderer.java

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// CommandLinkRenderer.java

package com.sun.faces.renderkit.html_basic;

import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;

import javax.faces.component.UICommand;
import javax.faces.component.UIComponent;
import javax.faces.component.behavior.ClientBehaviorContext;
import javax.faces.component.behavior.ClientBehavior;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.event.ActionEvent;

import com.sun.faces.RIConstants;
import com.sun.faces.renderkit.Attribute;
import com.sun.faces.renderkit.AttributeManager;
import com.sun.faces.renderkit.RenderKitUtils;
import com.sun.faces.util.MessageUtils;


/**
 * <B>CommandLinkRenderer</B> is a class that renders the current value of
 * <code>UICommand<code> as a HyperLink that acts like a Button.
 */

public class CommandLinkRenderer extends LinkRenderer {

    private static final Attribute[] ATTRIBUTES =
          AttributeManager.getAttributes(AttributeManager.Key.COMMANDLINK);


    private static final String SCRIPT_STATE = RIConstants.FACES_PREFIX +
                                               "scriptState";

    // ---------------------------------------------------------- Public Methods


    @Override
    public void decode(FacesContext context, UIComponent component) {

        rendererParamsNotNull(context, component);

        if (!shouldDecode(component)) {
            return;
        }

        String clientId = decodeBehaviors(context, component);

        if (wasClicked(context, component, clientId)) {
            component.queueEvent(new ActionEvent(component));
            if (logger.isLoggable(Level.FINE)) {
                logger.fine("This commandLink resulted in form submission " +
                            " ActionEvent queued.");

            }
        }

    }


    @Override
    public void encodeBegin(FacesContext context, UIComponent component)
          throws IOException {

        rendererParamsNotNull(context, component);

        if (!shouldEncode(component)) {
            return;
        }

        boolean componentDisabled =
              Boolean.TRUE.equals(component.getAttributes().get("disabled"));

        String formClientId = RenderKitUtils.getFormClientId(component, context);

        if (componentDisabled || formClientId == null) {
            renderAsDisabled(context, component);
        } else {
            RenderKitUtils.renderJsfJs(context);
            renderAsActive(context, component);
        }

    }


    @Override
    public void encodeChildren(FacesContext context, UIComponent component)
          throws IOException {

        rendererParamsNotNull(context, component);

        if (!shouldEncodeChildren(component)) {
            return;
        }

        if (component.getChildCount() > 0) {
            for (UIComponent kid : component.getChildren()) {
                encodeRecursive(context, kid);
            }
        }
        
    }


    @Override
    public void encodeEnd(FacesContext context, UIComponent component)
          throws IOException {

        rendererParamsNotNull(context, component);

        if (!shouldEncode(component)) {
            return;
        }

        ResponseWriter writer = context.getResponseWriter();
        assert(writer != null);
        String formClientId = RenderKitUtils.getFormClientId(component, context);
        if (formClientId == null) {
            writer.write(MessageUtils.getExceptionMessageString(
                  MessageUtils.COMMAND_LINK_NO_FORM_MESSAGE_ID));
            writer.endElement("span");
            return;
        }

        if (Boolean.TRUE.equals(component.getAttributes().get("disabled"))) {
            writer.endElement("span");
        } else {
            writer.endElement("a");
        }

    }


    @Override
    public boolean getRendersChildren() {

        return true;

    }

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


    @Override
    protected Object getValue(UIComponent component) {

        return ((UICommand) component).getValue();       

    }

    /*
     * Render the necessary Javascript for the link.
     * Note that much of this code is shared with CommandButtonRenderer.renderOnClick
     * RELEASE_PENDING: Consolidate this code into a utility method, if possible.
     */
    protected void renderAsActive(FacesContext context, UIComponent command)
          throws IOException {

        ResponseWriter writer = context.getResponseWriter();
        assert(writer != null);
        String formClientId = RenderKitUtils.getFormClientId(command, context);
        if (formClientId == null) {
            return;
        }

        //make link act as if it's a button using javascript        
        writer.startElement("a", command);
        writeIdAttributeIfNecessary(context, writer, command);
        writer.writeAttribute("href", "#", "href");
        RenderKitUtils.renderPassThruAttributes(context,
                                                writer,
                                                command,
                                                ATTRIBUTES,
                                                getNonOnClickBehaviors(command));

        RenderKitUtils.renderXHTMLStyleBooleanAttributes(writer, command);

        String target = (String) command.getAttributes().get("target");
        if (target != null) {
            target = target.trim();
        } else {
            target = "";
        }

        Collection<ClientBehaviorContext.Parameter> params = getBehaviorParameters(command);
        RenderKitUtils.renderOnclick(context, 
                                     command,
                                     params,
                                     target,
                                     true);

        writeCommonLinkAttributes(writer, command);

        // render the current value as link text.
        writeValue(command, writer);
        writer.flush();

    }

    // --------------------------------------------------------- Private Methods

    private static boolean wasClicked(FacesContext context,
                                      UIComponent component,
                                      String clientId) {

        Map<String,String> requestParamMap =
              context.getExternalContext().getRequestParameterMap();

        if (clientId == null) {
            clientId = component.getClientId(context);
        }

        // Fire an action event if we've had a traditional (non-Ajax)
        // postback, or if we've had a partial or behavior-based postback.
        return (requestParamMap.containsKey(clientId) ||
                RenderKitUtils.isPartialOrBehaviorAction(context, clientId));
    }

    // Returns the Behaviors map, but only if it contains some entry other
    // than those handled by renderOnclick().  This helps us optimize
    // renderPassThruAttributes() in the very common case where the
    // link only contains an "action" (or "click") Behavior.  In that
    // we pass a null Behaviors map into renderPassThruAttributes(),
    // which allows us to take a more optimized code path.
    private static Map<String, List<ClientBehavior>> getNonOnClickBehaviors(UIComponent component) {

        return getPassThruBehaviors(component, "click", "action");
    }


} // end of class CommandLinkRenderer