Programming academy

JSF2 – p:remoteCommand Example Chat Primefaces

p:remoteCommand chiama un metodo di un backing bean (tramite actionlistener) e, fondamentalemnte, fa da trigger ad uno javascript(oncomplete):

<p:remoteCommand name="nextMessage"
  actionListener="#{messageBean.firstUnreadMessage}"
  oncomplete="javascript:updateMessages(xhr, status, args);" />

Back-End

MessageBean.java

package com;

import java.io.Serializable;
import java.util.Collections;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
import javax.ejb.EJB;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
import javax.faces.event.ActionEvent;
import org.primefaces.context.RequestContext;


@ManagedBean
@ViewScoped
public class MessageBean implements Serializable {
 
  
 
    private final List messages;
    private Date lastUpdate;
    private Message message;
 
    /**
     * Creates a new instance of MessageBean
     */
    public MessageBean() {
        messages = Collections.synchronizedList(new LinkedList());
        lastUpdate = new Date(0);
        message = new Message();
    }
 
    public Date getLastUpdate() {
        return lastUpdate;
    }
 
    public void setLastUpdate(Date lastUpdate) {
        this.lastUpdate = lastUpdate;
    }
 
    public Message getMessage() {
        return message;
    }
 
    public void setMessage(Message message) {
        this.message = message;
    }
 
 
    public void firstUnreadMessage(ActionEvent evt) {
       RequestContext ctx = RequestContext.getCurrentInstance();

       ctx.addCallbackParam("ok", message!=null);
       if(message==null)
           return;
 
       lastUpdate = message.getDateSent();
 
       ctx.addCallbackParam("user", message.getUser());
       ctx.addCallbackParam("dateSent", new Date().toString());
       ctx.addCallbackParam("text", message.getMessage());
 
    }
 
}

Message.java

package com;
import java.io.Serializable;

public class Message implements Serializable {
    private Date dateSent;
    private String user;
    private String message;
 
    public Date getDateSent() {
        return dateSent;
    }
 
    public void setDateSent(Date dateSent) {
        this.dateSent = dateSent;
    }
 
    public String getMessage() {
        return message;
    }
 
    public void setMessage(String message) {
        this.message = message;
    }
 
    public String getUser() {
        return user;
    }
 
    public void setUser(String user) {
        this.user = user;
    }
}

Front-End

Chat1.xhtml

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
 xmlns:h="http://java.sun.com/jsf/html"
 xmlns:p="http://primefaces.org/ui">
<h:head>
 <title>Chat test!</title>
 <script type="text/javascript"
  src="#{facesContext.externalContext.requestContextPath}/util.js"></script>

</h:head>

<h:body>
 <h:form prependId="false">
  <h:panelGrid columns="2">
                Name: <p:inputText value="#{messageBean.message.user}" />
                Text: <p:inputText
    value="#{messageBean.message.message}" />
   <p:commandButton type="reset" value="Clear" />
   <p:commandButton value="Send!"
    actionListener="#{messageBean.sendMessage}" onclick="nextMessage();" />
  </h:panelGrid>
  <p:remoteCommand name="nextMessage"
   actionListener="#{messageBean.firstUnreadMessage}"
   oncomplete="javascript:updateMessages(xhr, status, args);" />
 </h:form>

 <hr />
 <h3>Live chat</h3>
 <div id="chat"></div>
</h:body>
</html>

util.js


        function updateMessages(xhr, status, args) {
            if(!args.ok) return;
            $('#chat').append('<div class="msg">[' +args.dateSent+ '] <strong>'+args.user+'</strong>: '+args.text+'</div>');
        }

Esecuzione

lanciando da browser l’url

http://localhost:8080/JSFProject/faces/chat1.xhtml

si ha una simulazione di chat

HQL – Like parameter

Hql con un parametro in input da mettere nella like con le percentuali:

String querySql = "select u from Users u  ";
String  whereSql = whereSql + " u.currentLocation like :currentLocation";
querySql = querySql + whereSql;

Query q = this.getEntityManager().createQuery(querySql);
q.setParameter("currentLocation", '%'+user.getCurrentLocation()+'%');

JSF2 – Bean Method Call With Parameter

Un metodo di un bean può ricevere in input parametri da una pagina jsf:
#{bean.method(param)}
Questa sintassi funziona con Tomcat 7, perchè supporta le EL 2.2 (el-impl-2.2.jar).

passParameter.xhtml

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
 xmlns:f="http://java.sun.com/jsf/core"
 xmlns:h="http://java.sun.com/jsf/html"
 xmlns:ui="http://java.sun.com/jsf/facelets"
 xmlns:p="http://primefaces.org/ui"
 xmlns:c="http://java.sun.com/jsp/jstl/core">
<h:head/>
<h:body>
 <h:form>
<h:commandButton action="#{passParameterBean.getParameter(gigi)}" />

 </h:form>
</h:body>
</html>

PassParameter.java

package com;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

@ManagedBean
@SessionScoped
public class PassParameterBean {
 
 private String name;

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }
 
 
 public String getParameter(String name)
 {
  this.name = name;
  
  return "./passParameterResult.xhtml";
 }

}

PassParameterResult.xhtml

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
 xmlns:f="http://java.sun.com/jsf/core"
 xmlns:h="http://java.sun.com/jsf/html"
 xmlns:ui="http://java.sun.com/jsf/facelets"
 xmlns:p="http://primefaces.org/ui"
 xmlns:c="http://java.sun.com/jsp/jstl/core">
<h:head />
<h:body>
 <h:form>
  <h:outputText value="#{passParameterBean.name}" />

 </h:form>
</h:body>
</html>

JSF2 Primefaces – p:galleria Example

p:galleria è un tag per la visualizzazione delle immagini:

<p:galleria value=”#{galleriaBean.images}” var=”image” >

<p:graphicImage value=”/resources/images/#{image}” />

</p:galleria>

Si hanno a disposizione vari effetti:
http://primefaces-rocks.appspot.com/ui/galleria.jsf

Bean java e pagina xhtml

galleria.xhtml

<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
<html xmlns=”http://www.w3.org/1999/xhtml”
xmlns:f=”http://java.sun.com/jsf/core”
xmlns:h=”http://java.sun.com/jsf/html”
xmlns:ui=”http://java.sun.com/jsf/facelets”
xmlns:p=”http://primefaces.org/ui”
xmlns:c=”http://java.sun.com/jsp/jstl/core”>
<h:head/>
<h:body>
<h:form>
<h3>Images1 </h3>
<p:galleria value=”#{galleriaBean.images}” var=”image” panelWidth=”500″ panelHeight=”313″ effectSpeed=”1000″>
<p:graphicImage value=”/resources/images/#{image}” />
</p:galleria>

<h3>Custom Content</h3>
<p:galleria id=”contentGalleria” value=”#{galleriaBean.players}” var=”player” panelWidth=”250″ panelHeight=”300″
frameWidth=”48″ frameHeight=”65″ effect=”clip”>

<p:graphicImage id=”playerImage” value=”/resources/images/#{player.photo}” alt=”#{image}” title=”#{player.name}”/>
<f:facet name=”content”>
<h:panelGrid columns=”2″ cellpadding=”5″>
<f:facet name=”header”>
<p:graphicImage value=”/resources/images/#{player.photo}” />
</f:facet>

<h:outputText value=”Name: ” />
<h:outputText id=”name” value=”#{player.name}”/>

<h:outputText value=”Number ” />
<h:outputText id=”number” value=”#{player.number}”/>

<h:outputText value=”Position ” />
<h:outputText id=”position” value=”#{player.position}”/>
</h:panelGrid>
</f:facet>

</p:galleria>
</h:form>
</h:body>
</html>

GalleriaBean.java

package com;

import java.util.ArrayList;
import java.util.List;
import java.util.ResourceBundle;

import javax.annotation.PostConstruct;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import javax.faces.context.FacesContext;
import javax.faces.event.AjaxBehaviorEvent;

import java.util.ArrayList;
import java.util.List;
import javax.annotation.PostConstruct;

@ManagedBean
@SessionScoped
public class GalleriaBean {

private List<String> images;

private List<Player> players;

private Player selectedPlayer;

@PostConstruct
public void init() {
images = new ArrayList<String>();

for(int i=1;i<=12;i++) {
images.add(“photoProfile.png”);
}

players = new ArrayList<Player>();

players.add(new Player(“Messi”, 10, “photoProfile.png”, “CF”));
players.add(new Player(“Iniesta”, 8, “photoProfile.png”, “CM”));
players.add(new Player(“Villa”, 7, “photoProfile.png”, “CF”));
players.add(new Player(“Xavi”, 6, “photoProfile.png”, “CM”));
players.add(new Player(“Puyol”, 5, “photoProfile.png”, “CB”));
}

public Player getSelectedPlayer() {
return selectedPlayer;
}

public void setSelectedPlayer(Player selectedPlayer) {
this.selectedPlayer = selectedPlayer;
}


public List<String> getImages() {
return images;
}

public List<Player> getPlayers() {
return players;
}
}

Esecuzione
Deployando e, da browser, chiamando l’url:

http://localhost:8080/JSFProject/faces/galleria.xhtml

si ottiene:

JSF2 – Load Properties File Dentro Bean

Legge un file di properties (configurationFBM) da dentro un Backing Bean:

Java Read Properties File Servlet

Ipotizzando che il file di properties si trovi sotto

web-infclassescomprova.properties

dentro la servlet è sufficiente la seguente istruzione

ResourceBundle handlers = ResourceBundle.getBundle(“com.prova”);

Spring 3 @autowired Esempio

@autowired è usata per iniettare direttamente i valori configurati nell’xml nel bean.
Si puo usare sul metodo set, costruttore o direttamente sul campo.

Bean

Bean dichiarato nel file xml con un solo campo msg.

package com;

public class Message {

private String author;
private String body;

public String getAuthor() {
return author;
}

public void setAuthor(String author) {
this.author = author;
}

public String getBody() {
return body;
}

public void setBody(String body) {
this.body = body;
}

}

applicatioContext.xml

</beans>

Abilitazione Annotazione

Per usare @autowired si deve registrare AutowiredAnnotationBeanPostProcessor. Questo si può fare in due modi:

1) si aggiunge

<context:annotation-config />

dentro applicationContext.xml

2) si aggiunge:

<bean class=”org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor”/> dentro applicationContext.xml

@autowired Esempi
@autowired su campo

ProvaBean.java

package com;

import org.springframework.beans.factory.annotation.Autowired;

public class ProvaBean {
@Autowired
private Message message;

public Message getMessage() {
return message;
}

public void setMessage(Message message) {
this.message = message;
}

}

@autowired sul metodo set

ProvaBean.java

package com;

import org.springframework.beans.factory.annotation.Autowired;

public class ProvaBean {

private Message message;

public Message getMessage() {
return message;
}

@Autowired
public void setMessage(Message message) {
this.message = message;
}

}

@autowired sul costruttore

ProvaBean.java

package com;

import org.springframework.beans.factory.annotation.Autowired;

public class ProvaBean {

private Message message;

@Autowired
public ProvaBean(Message msg)
{
message = msg;
}

public Message getMessage() {
return message;
}

public void setMessage(Message message) {
this.message = message;
}

}

Esecuzione Test

TestBean.java

package com;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestBean {

public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext(
“applicationContext.xml”);

ProvaBean obj = (ProvaBean) context.getBean(“provaBean”);
System.out.println(obj.getMessage().getBody());
System.out.println(obj.getMessage().getAuthor());
}

}

avviando il main si otterrà, in tutte e tre casi, il seguente output:

Java Reflection Esempio

Copiare due classi diverse ma con gli stessi campi tramite la reflection

Bean

A.java

package com;

import java.lang.reflect.Field;

public class A {
private String name;

private long punteggio;

public long getPunteggio() {
return punteggio;
}

public void setPunteggio(long punteggio) {
this.punteggio = punteggio;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}

B.java

package com;

import java.lang.reflect.Field;
import java.lang.reflect.Method;

public class B {
private String name;

private long punteggio;

public long getPunteggio() {
return punteggio;
}

public void setPunteggio(long punteggio) {
this.punteggio = punteggio;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public void copy(Object obj) {
try {

Method[] methods = obj.getClass().getMethods();

for (int i = 0; i < methods.length; i++) {
String methodName = methods[i].getName();
try{
if(methodName.startsWith(“get”)){
this.getClass().getMethod(methodName.replaceFirst(“get”, “set”) , methods[i].getReturnType() ).invoke(this, methods[i].invoke(obj, null));
}else if(methodName.startsWith(“is”) ){
this.getClass().getMethod(methodName.replaceFirst(“is”, “set”) , methods[i].getReturnType() ).invoke(this, methods[i].invoke(obj, null));
}

}catch (NoSuchMethodException e) {
// TODO: handle exception
}catch (IllegalArgumentException e) {
// TODO: handle exception
}

}

} catch (Exception ex) {
ex.printStackTrace();
}
}

}

Classe per il test:

TestReflection.java

package com;

public class TestReflection {

public static void main(String[] args) {

A obj1 = new A();

obj1.setName(“hello world”);

A obj2 = new A();

obj2.copy(obj1);

System.out.println(“name obj copy with reflection:”+obj2.getName());

}

Esecuzione

lanciando il main si ottiene una copia identica dell’istanza obj1:

Spring 3 Bean Example

Configurazione
Mettere il seguente file dentro la cartella resources.

applicationContext.xml

<context:component-scan base-package=”com” />

Bean Spring

creare un file java di nome ProvaBean nel package “com”

ProvaBean.java

package com;

public class ProvaBean {

private String msg = “HelloWord”;

public String getMsg() {

return msg;

}

public void setMsg(String msg) {

this.msg = msg;

}

creare un file java di nome TestBean:

TestBean.java

package com;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestBean {

public static void main(String[] args) {

ApplicationContext context = new ClassPathXmlApplicationContext(

“applicationContext.xml”);

ProvaBean obj = (ProvaBean) context.getBean(“provaBean”);

System.out.println(obj.getMsg());

}

Esecuzione

lanciare il main del file TestBean. L’ouput sarà:

Programming academy

Articoli

JSF2 – p:remoteCommand Example Chat Primefaces

Java StringTokenizer Example

HQL – Like parameter

JSF2 – Bean Method Call With Parameter

JSF2 Primefaces – p:galleria Example

JSF2 – Load Properties File Dentro Bean

Java Read Properties File Servlet

Spring 3 @autowired Esempio

Java Reflection Esempio

Spring 3 Bean Example