MessagesRenderer.java

/*
 * Copyright 2017 OmniFaces
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package org.omnifaces.renderer;

import static org.omnifaces.util.Components.forEachComponent;
import static org.omnifaces.util.Messages.createInfo;
import static org.omnifaces.util.Renderers.writeAttribute;
import static org.omnifaces.util.Renderers.writeAttributes;
import static org.omnifaces.util.Renderers.writeText;
import static org.omnifaces.util.Utils.coalesce;
import static org.omnifaces.util.Utils.isEmpty;
import static org.omnifaces.util.Utils.isOneOf;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.faces.application.FacesMessage;
import javax.faces.application.FacesMessage.Severity;
import javax.faces.component.UIComponent;
import javax.faces.component.UIInput;
import javax.faces.component.UIMessages;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.render.FacesRenderer;
import javax.faces.render.Renderer;

import org.omnifaces.component.messages.OmniMessages;
import org.omnifaces.util.Callback;

/**
 * This renderer is the default renderer of {@link OmniMessages}. It's basically copypasted from Mojarra 2.2,
 * including the fix of tooltip rendering as described in <a href="http://java.net/jira/browse/JAVASERVERFACES-2160">
 * issue 2160</a>, and afterwards slightly rewritten, refactored and enhanced to take the new features into account.
 *
 * @author Bauke Scholtz
 * @since 1.5
 */
@FacesRenderer(componentFamily=UIMessages.COMPONENT_FAMILY, rendererType=MessagesRenderer.RENDERER_TYPE)
public class MessagesRenderer extends Renderer {

	// Public constants -----------------------------------------------------------------------------------------------

	/** The standard renderer type. */
	public static final String RENDERER_TYPE = "org.omnifaces.Messages";

	// Private constants ----------------------------------------------------------------------------------------------

	private static final String LAYOUT_TABLE = "table";
	private static final Map<Severity, String> SEVERITY_NAMES = createSeverityNames();

	private static Map<Severity, String> createSeverityNames() {
		Map<Severity, String> severityNames = new HashMap<>();
		severityNames.put(FacesMessage.SEVERITY_INFO, "info");
		severityNames.put(FacesMessage.SEVERITY_WARN, "warn");
		severityNames.put(FacesMessage.SEVERITY_ERROR, "error");
		severityNames.put(FacesMessage.SEVERITY_FATAL, "fatal");
		return Collections.unmodifiableMap(severityNames);
	}

	// Actions --------------------------------------------------------------------------------------------------------

	/**
	 * Returns <code>true</code>.
	 */
	@Override
	public boolean getRendersChildren() {
		return true;
	}

	@Override
	public void encodeChildren(FacesContext context, UIComponent component) throws IOException {
		if (!component.isRendered()) {
			return;
		}

		OmniMessages omniMessages = (OmniMessages) component;
		List<FacesMessage> messages = getMessages(context, omniMessages);

		if (!isEmpty(omniMessages.getVar()) && omniMessages.getChildCount() > 0) {
			encodeMessagesRepeater(context, omniMessages, messages);
		}
		else if (messages.isEmpty()) {
			encodeEmptyMessages(context, omniMessages);
		}
		else {
			String message = omniMessages.getMessage();

			if (!isEmpty(message)) {
				messages = Arrays.asList(createInfo(message));
			}

			encodeMessages(context, omniMessages, messages, LAYOUT_TABLE.equals(omniMessages.getLayout()));
		}
	}

	/**
	 * Collect all messages associated with components identified by <code>for</code> attribute and return it. An empty
	 * list will be returned when there are no messages.
	 * @param context The involved faces context.
	 * @param component The messages component.
	 * @return All messages associated with components identified by <code>for</code> attribute.
	 */
	protected List<FacesMessage> getMessages(final FacesContext context, OmniMessages component) {
		String forClientIds = component.getFor();

		if (forClientIds == null) {
			return component.isGlobalOnly() ? context.getMessageList(null) : context.getMessageList();
		}

		final List<FacesMessage> messages = new ArrayList<>();

		for (String forClientId : forClientIds.split("\\s+")) {
			UIComponent forComponent = component.findComponent(forClientId);

			if (forComponent == null) {
				continue;
			}

			messages.addAll(context.getMessageList(forComponent.getClientId(context)));

			if (!(forComponent instanceof UIInput)) {
				forEachComponent(context).fromRoot(forComponent).ofTypes(UIInput.class).invoke(new Callback.WithArgument<UIInput>() {
					@Override
					public void invoke(UIInput input) {
						messages.addAll(context.getMessageList(input.getClientId(context)));
					}
				});
			}
		}

		return messages;
	}

	/**
	 * Encode the case when the <code>var</code> attribute is specified. This will render without any HTML markup and
	 * put the current message in the request scope as identified by the <code>var</code> attribute.
	 * Note: the iteration is by design completely stateless.
	 * @param context The involved faces context.
	 * @param component The messages component.
	 * @param messages The queued faces messages.
	 * @throws IOException When an I/O error occurs.
	 */
	protected void encodeMessagesRepeater(FacesContext context, OmniMessages component, List<FacesMessage> messages)
		throws IOException
	{
		String var = component.getVar();
		Map<String, Object> requestMap = context.getExternalContext().getRequestMap();
		Object originalVar = requestMap.get(var);

		try {
			for (FacesMessage message : messages) {
				if (message.isRendered() && !component.isRedisplay()) {
					continue;
				}

				requestMap.put(var, message);

				for (UIComponent child : component.getChildren()) {
					child.encodeAll(context);
				}

				message.rendered();
			}
		}
		finally {
			if (originalVar != null) {
				requestMap.put(var, originalVar);
			}
			else {
				requestMap.remove(var);
			}
		}
	}

	/**
	 * Encode the case when there are no messages. This will render a div when the ID is specified.
	 * @param context The involved faces context.
	 * @param component The messages component.
	 * @throws IOException When an I/O error occurs.
	 */
	protected void encodeEmptyMessages(FacesContext context, OmniMessages component) throws IOException {
		String id = component.getId();

		if (!isOneOf(id, null, "javax_faces_developmentstage_messages")) {
			ResponseWriter writer = context.getResponseWriter();
			writer.startElement("div", component);
			writeAttribute(writer, "id", component.getClientId(context));
			writer.endElement("div");
		}
	}

	/**
	 * Encode the case when the faces messages are to be rendered as either a HTML table or a HTML list.
	 * @param context The involved faces context.
	 * @param component The messages component.
	 * @param messages The queued faces messages.
	 * @param table Whether to render the messages as a HTML table or a HTML list.
	 * @throws IOException When an I/O error occurs.
	 */
	protected void encodeMessages
		(FacesContext context, OmniMessages component, List<FacesMessage> messages, boolean table)
			throws IOException
	{
		ResponseWriter writer = context.getResponseWriter();
		writer.startElement(table ? LAYOUT_TABLE : "ul", component);
		writeAttribute(writer, "id", component.getClientId(context));
		writeAttribute(writer, component, "styleClass", "class");
		writeAttributes(writer, component, "style", "title", "lang", "dir");

		for (FacesMessage message : messages) {
			if (!message.isRendered() || component.isRedisplay()) {
				encodeMessage(context, component, message, table);
				message.rendered();
			}
		}

		writer.endElement(table ? LAYOUT_TABLE : "ul");
	}

	/**
	 * Encode a single faces message.
	 * @param context The involved faces context.
	 * @param component The messages component.
	 * @param message The queued faces message.
	 * @param table Whether to render the messages as a HTML table or a HTML list.
	 * @throws IOException When an I/O error occurs.
	 */
	protected void encodeMessage(FacesContext context, OmniMessages component, FacesMessage message, boolean table) throws IOException {
		ResponseWriter writer = context.getResponseWriter();
		writer.startElement(table ? "tr" : "li", component);
		String severityName = SEVERITY_NAMES.get(message.getSeverity());
		writeAttribute(writer, component, severityName + "Style", "style");
		writeAttribute(writer, component, severityName + "Class", "class", "styleClass");

		if (table) {
			writer.startElement("td", component);
		}

		String summary = coalesce(message.getSummary(), "");
		String detail = coalesce(message.getDetail(), summary);

		if (component.isTooltip() && isEmpty(component.getTitle())) {
			writeAttribute(writer, "title", detail);
		}

		if (component.isShowSummary()) {
			writeText(writer, component, summary, component.isEscape());

			if (component.isShowDetail()) {
				writer.write(" ");
			}
		}

		if (component.isShowDetail()) {
			writeText(writer, component, detail, component.isEscape());
		}

		if (table) {
			writer.endElement("td");
		}

		writer.endElement(table ? "tr" : "li");
	}

}