Displaying Guestbook Entries

Building the Web Front-End

Step 10 of 11

To display guestbook entries, you must do the reverse of what you did to store them: retrieve them the database, loop through them, and present them on the page. To do this, you must override the default MVC Portlet render method so you can tell your portlet how to render itself.

Rendering the Portlet

Add the following render method to GuestbookPortlet:

@Override
public void render(RenderRequest renderRequest, RenderResponse renderResponse)
    throws IOException, PortletException {

    try {
        ServiceContext serviceContext = ServiceContextFactory.getInstance(
            Guestbook.class.getName(), renderRequest);

        long groupId = serviceContext.getScopeGroupId();

        long guestbookId = ParamUtil.getLong(renderRequest, "guestbookId");

        List<Guestbook> guestbooks = _guestbookLocalService.getGuestbooks(
            groupId);

        if (guestbooks.isEmpty()) {
            Guestbook guestbook = _guestbookLocalService.addGuestbook(
                serviceContext.getUserId(), "Main", serviceContext);

            guestbookId = guestbook.getGuestbookId();
        }

        if (guestbookId == 0) {
            guestbookId = guestbooks.get(0).getGuestbookId();
        }

        renderRequest.setAttribute("guestbookId", guestbookId);
    }
    catch (Exception e) {
        throw new PortletException(e);
    }

    super.render(renderRequest, renderResponse);
}

This render method checks for guestbooks in the current Site. If there aren’t any, it creates one. The guestbookId that it has (either the first one or one that has been selected in functionality you haven’t written yet) is set in the request object so that it becomes the current guestbook.

Press [CTRL]+[SHIFT]+O to organize imports and then save the file.

Note: When you are prompted to choose imports, here are some guidelines:

Always use org.osgi... packages instead of aQute.bnd...
Generally use java.util... or javax.portlet... packages.
You never use java.awt... in this project.
Only use com.liferay... when it is for a Liferay specific implementation or your custom implementation of a concept.

For example:

If you are given the choice between javax.portlet.Portlet and com.liferay.portlet.Portlet choose javax.portlet.Portlet.
If you are given the choice between org.osgi.component and aQute.bnd.annotation.component choose org.osgi.component

If at some point you think you chose an incorrect import, but you’re not sure what it might be, you can erase all of the imports from the file and press [CTRL]+[SHIFT]+O again and see if you can identify where you went wrong.

Now that you have your controller preparing your data for display, your next step is to implement the view so users can see guestbook entries.

Liferay’s development framework makes it easy to loop through data and display it nicely to the end user. You’ll use a Liferay UI construct called Search Container to make this happen.

Replace the contents of view.jsp with this code:

<%@include file="../init.jsp"%>

<%
long guestbookId = Long.valueOf((Long) renderRequest
        .getAttribute("guestbookId"));
%>

<aui:button-row cssClass="guestbook-buttons">

    <portlet:renderURL var="addEntryURL">
        <portlet:param name="mvcPath" value="/guestbook/edit_entry.jsp" />
        <portlet:param name="guestbookId"
            value="<%=String.valueOf(guestbookId)%>" />
    </portlet:renderURL>

    <aui:button onClick="<%=addEntryURL.toString()%>" value="Add Entry"></aui:button>

</aui:button-row>

<liferay-ui:search-container total="<%=GuestbookEntryLocalServiceUtil.getGuestbookEntriesCount()%>">
<liferay-ui:search-container-results
    results="<%=GuestbookEntryLocalServiceUtil.getGuestbookEntries(scopeGroupId.longValue(),
                    guestbookId, searchContainer.getStart(),
                    searchContainer.getEnd())%>" />

<liferay-ui:search-container-row
    className="com.liferay.docs.guestbook.model.GuestbookEntry" modelVar="entry">

    <liferay-ui:search-container-column-text property="message" />

    <liferay-ui:search-container-column-text property="name" />

    <liferay-ui:search-container-column-jsp
        align="right"
        path="/guestbook/entry_actions.jsp" />

</liferay-ui:search-container-row>

<liferay-ui:search-iterator />

</liferay-ui:search-container>

You’ve used a lot of new objects in this JSP, so you must declare them in init.jsp. Replace the contents of init.jsp with this:

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/portlet_2_0" prefix="portlet"%>
<%@ taglib uri="http://liferay.com/tld/aui" prefix="aui"%>
<%@ taglib uri="http://liferay.com/tld/portlet" prefix="liferay-portlet"%>
<%@ taglib uri="http://liferay.com/tld/theme" prefix="liferay-theme"%>
<%@ taglib uri="http://liferay.com/tld/ui" prefix="liferay-ui"%>
<%@ taglib uri="http://liferay.com/tld/frontend" prefix="liferay-frontend" %>
<%@ taglib uri="http://liferay.com/tld/security" prefix="liferay-security" %>

<%@ page import="java.util.List" %>
<%@ page import="com.liferay.portal.kernel.util.ParamUtil" %>
<%@ page import="com.liferay.portal.kernel.util.HtmlUtil" %>
<%@ page import="com.liferay.portal.kernel.util.WebKeys" %>
<%@ page import="com.liferay.petra.string.StringPool" %>
<%@ page import="com.liferay.portal.kernel.model.PersistedModel" %>
<%@ page import="com.liferay.portal.kernel.dao.search.SearchEntry" %>
<%@ page import="com.liferay.portal.kernel.dao.search.ResultRow" %>
<%@ page import="com.liferay.docs.guestbook.model.Guestbook" %>
<%@ page import="com.liferay.docs.guestbook.service.GuestbookEntryLocalServiceUtil" %>
<%@ page import="com.liferay.docs.guestbook.service.GuestbookLocalServiceUtil" %>
<%@ page import="com.liferay.docs.guestbook.model.GuestbookEntry" %>

<liferay-theme:defineObjects />

<portlet:defineObjects />

Many of these objects, such as HtmlUtil, ParamUtil, and StringPool, are Liferay helper utilities that enable you with a single line of code do things like extract parameters, escape data, or provide Strings that otherwise have to be escaped.

Save your work.

Creating an Actions JSP

Actions can be performed on your entities once they’re stored. Users who enter Guestbook entries may wish to edit them or delete them. Now you’ll provide that functionality.

Right-click on the src/main/resources/META-INF/resources/guestbook folder and select New → File.
Name the file entry_actions.jsp.

Paste the following code into the file:

<%@include file="../init.jsp"%>

<%
String mvcPath = ParamUtil.getString(request, "mvcPath");

ResultRow row = (ResultRow)request.getAttribute(WebKeys.SEARCH_CONTAINER_RESULT_ROW);

GuestbookEntry entry = (GuestbookEntry)row.getObject();
%>

<liferay-ui:icon-menu>

        <portlet:renderURL var="editURL">
            <portlet:param name="entryId"
                value="<%= String.valueOf(entry.getEntryId()) %>" />
            <portlet:param name="mvcPath" value="/guestbook/edit_entry.jsp" />
        </portlet:renderURL>

        <liferay-ui:icon image="edit" message="Edit"
            url="<%=editURL.toString() %>" />

        <portlet:actionURL name="deleteEntry" var="deleteURL">
            <portlet:param name="entryId"
                value="<%= String.valueOf(entry.getEntryId()) %>" />
            <portlet:param name="guestbookId"
                value="<%= String.valueOf(entry.getGuestbookId()) %>" />
        </portlet:actionURL>

        <liferay-ui:icon-delete url="<%=deleteURL.toString() %>" />

</liferay-ui:icon-menu>

You may have noticed this JSP was included in the Search Container rows in your view.jsp. As the Search Container loops through Guestbook entries, this JSP generates an Actions button for each of them containing two functions: a call to your addEntry method (which both adds and edits) and a call to your deleteEntry method. Both calls supply the current guestbookId and entryId parameters so the Action method has everything it needs to call the service method that does the work.

Awesome! You’ve now completed the first iteration of your Guestbook application.

Figure 1: You have a form to enter information.