Sunday, April 5, 2015

Working with Expando API in Liferay

Nagul Meera Mahankali

Liferay have introduced Expando API to extending existed Liferay tables to add additional columns rather than creating new tables in the database.

Logically its look like new tables in Liferay but originally it won’t be created in the Liferay database.

All Expando mechanism is organized by following four tables which are already created in the Liferay database.

ExpandoTable

This will manage the brand new table information its means virtual tables information

ExpandoColumn

It manages the columns information related to respective Expando table.

ExpandoRow

It will used to manage table rows related to respective Expando table

ExpandoValue

Originally data will be stored in this table and it will mapped with Expando table and Expando row.

From above four tables we can create many tables logically and which act like original tables in database.

Advantages:

We can extend existed Liferay tables

Liferay have implemented custom fields for User, Site, Role and Organization it will use the Expando mechanism to create additional fields so that it will be extending the original User_, Role_, Organization_ and Group_ tables.

http://www.liferaysavvy.com/2014/02/introduction-to-liferay-custom.html

http://www.liferaysavvy.com/2014/02/working-with-liferay-custom-fields.html

We can Logically Create brand new tables and columns

We can also create new tables and columns in our real time requirement and when we created tables and columns using Expando we don’t need to write any service layer implementation to data storage and retrieval and with help of Expando API classes we can store and retrieve data.

Best example for above is Webform Portlet. This will use Expando API to create brand new tables and columns to each form based on fields we have created for webform.

The data will be managed in brand new Expando table here for each form they will created tables and all form data will be stored in the respective Expando table.

Brand new table information available in ExpandoTable,

All columns information ExapndoColumn with mapping of Expando Table Id

For each form submission it will create new row in ExpandoRow table

Form data will be stored in ExpnadoValue and here for each input field data will create new record in ExpnadoValue table and stored with reference ids like ExpandoRow Id.

Liferay Expando API Implementation Example

Assume we are going to create employee form and employee consists of different fields.

Now we will use Expando API to store employee information and display in Portlet.

Employee Form Fields

First Name,

Last Name

Employee Designation

Email Address

Age

Phone Number

The following is Required Expando Artifacts in Implementation

Expando Table Name: Employee

Expando Columns

Column Name	Type
First Name,	String
Last Name	String
Employee Designation	String
Email Address	String
Age	Integer
Phone Number	String

Required Steps in Implementation

Need to create Expando Table and Name is Employee

Need to create Expando Columns for Employee with reference of Expando Table Id

Need to store data in Expando Value table with reference of Table Id, Expando Row Id

Note:

We need to remember that Expando Tables and Its columns only for one time creation and each employee form submission we will create ExpandoRow and Add values in ExpandoValue Table. For each filed in Employee form we will create new ExpandoValue record and store field data in it.

Here we need not to create ExpandoRow explicitly for each employee form submission, at the time of add values in ExpandoValue table rows will be crated automatically in ExpandoRow Table.

The following are Expando API classes we will use in Code Implementation

ExpandoTableLocalServiceUtil

ExpandoColumnLocalServiceUtil

ExpandoRowLocalServiceUtil

ExpandoValueLocalServiceUtil

From above classed we will use different API methods and the following are some of important method signatures

ExpandoTableLocalServiceUtil.addTable(companyId, XXXX.class.getName(), tableName);

ExpandoColumnLocalServiceUtil.addColumn(tableId,fieldName,ExpandoColumnConstants.STRING);

ExpandoColumnLocalServiceUtil.addColumn(tableId,fieldName,ExpandoColumnConstants.Integer);

ExpandoValueLocalServiceUtil.addValue(

companyId, XXXX.class.getName(), databaseTableName,

fieldLabel, classPK, fieldValue);

ExpandoColumnConstants provide values for column types such as int, long, String, long, double and Boolean.

Note:

ClassPK is kind of primary key we can generate as follows

long classPK = CounterLocalServiceUtil.increment(XXXX.class.getName());

long classPK = CounterLocalServiceUtil.increment();

Database Reference for Expando API

Expando API Example Portlet View Page

Expando API Example Portlet Add Employee Page

Expando API Example Portlet Display Employees Page

Download Liferay Expando API Example Portlet

https://sourceforge.net/projects/meeralferay/files/LiferayExpandoAPIExample/

Complete Code Example

view.jsp (/html/jsps/view.jsp)

<%@ 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://java.sun.com/portlet_2_0" prefix="portlet" %>

<portlet:defineObjects />

<liferay-theme:defineObjects />

<h1>Liferay Expando API Example</h1>

<portlet:renderURL var="addEmployee">

<portlet:param name="mvcPath" value="/html/jsps/add_employee.jsp"/>

</portlet:renderURL>

<portlet:renderURL var="dislayEmployees">

<portlet:param name="mvcPath" value="/html/jsps/display_employeed.jsp"/>

</portlet:renderURL>

<br/>

<a href="<%=addEmployee.toString()%>">Add Employee</a><br/>

<a href="<%=dislayEmployees.toString()%>">Display Employees</a><br/>

add_employee.jsp (/html/jsps/add_employee.jsp)

<%@page import="com.liferay.portal.kernel.servlet.SessionErrors"%>

<%@page import="com.liferay.portal.kernel.servlet.SessionMessages"%>

<%@ 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://java.sun.com/portlet_2_0" prefix="portlet" %>

<portlet:defineObjects />

<portlet:renderURL var="homeURL"></portlet:renderURL>

<portlet:actionURL var="addEmployeeActionURL" windowState="normal"

name="addEmployee">

</portlet:actionURL>

<% if(SessionMessages.contains(renderRequest.

getPortletSession(),"employee-add-success")){%>

<liferay-ui:success key="employee-add-success" message="Employee information

have been added successfully." />

<%} %>

<% if(SessionErrors.contains(renderRequest.getPortletSession(),

"employee-add-error")){%>

<liferay-ui:error key="employee-add-error" message="There is an

Error occured while adding employee and please try again" />

<%} %>

<h2>Add Employee</h2>

<form action="<%=addEmployeeActionURL%>" name="employeeForm" method="POST">

<b>First Name</b><br/>

<input type="text" name="<portlet:namespace/>employeeFirstName" id="<portlet:namespace/>employeeFirstName"/><br/>

<input type="text" name="<portlet:namespace/>employeeLastName" id="<portlet:namespace/>employeeLastName"/><br/>

<b>Employee Designation</b><br/>

<input type="text" name="<portlet:namespace/>employeeDesignation" id="<portlet:namespace/>employeeDesignation"/><br/>

<b>Email Address</b><br/>

<input type="text" name="<portlet:namespace/>emailAddress" id="<portlet:namespace/>emailAddress"/><br/>

<input type="text" name="<portlet:namespace/>employeeAge" id="<portlet:namespace/>employeeAge"/><br/>

<b>Phone Number</b><br/>

<input type="text" name="<portlet:namespace/>phoneNumber" id="<portlet:namespace/>phoneNumber"/><br/>

</form>

display_employeed.jsp (/html/jsps/display_employeed.jsp)

<%@page import="com.liferay.portlet.expando.NoSuchTableException"%>

<%@page import="com.liferay.portlet.expando.model.ExpandoTable"%>

<%@page import="com.liferay.portlet.expando.service.ExpandoTableLocalServiceUtil"%>

<%@page import="com.liferay.portal.kernel.util.StringPool"%>

<%@page import="com.liferay.portlet.expando.service.ExpandoValueLocalServiceUtil"%>

<%@page import="com.liferay.portlet.expando.model.ExpandoRow"%>

<%@page import="com.liferay.portal.kernel.dao.orm.QueryUtil"%>

<%@page import="com.meera.liferay.expandoapi.LiferayExpandoAPIAction"%>

<%@page import="java.util.List"%>

<%@page import="com.liferay.portlet.expando.service.ExpandoRowLocalServiceUtil"%>

<%@ 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://java.sun.com/portlet_2_0" prefix="portlet" %>

<portlet:defineObjects />

<liferay-theme:defineObjects />

<portlet:renderURL var="homeURL"></portlet:renderURL>

<h1>Liferay Expando API Display Employees</h1>

<tr>

<th>FirstName</th>

<th>LastName</th>

<th>Designation</th>

<th>EmailAddress</th>

<th>PhoneNumber</th>

</tr>

ExpandoTable expandoTable=null;

String message=null;

try {

expandoTable = ExpandoTableLocalServiceUtil.getTable(

themeDisplay.getCompanyId(), LiferayExpandoAPIAction.class.getName(),LiferayExpandoAPIAction.expandoTableName);

}

catch (NoSuchTableException nste) {

message="Table not existed to show the data. please add data first and comeback to to see the data";

}

if(expandoTable!=null){

List<ExpandoRow> rows = ExpandoRowLocalServiceUtil.getRows(

themeDisplay.getCompanyId(), LiferayExpandoAPIAction.class.getName(),

LiferayExpandoAPIAction.expandoTableName, QueryUtil.ALL_POS, QueryUtil.ALL_POS);

for (ExpandoRow row : rows) {

String data = ExpandoValueLocalServiceUtil.getData(

themeDisplay.getCompanyId(),