Human System

3/14/2008

File download in Click Framework

Click Framework provides FileField to upload file, however Click does not provide any support for file downloading. I made AbstractDownloadPage to download file.

Usage:

 public class SampleDownloadPage extends AbstractDownloadPage {
  public SampleDownloadPage(){
    setFileName("sample.txt");
    setContents(SampleDownloadPage.class.getResourceAsStream("sample.txt"));
  }
}

This page class does not have a template because response is written by this class. So auto-mapping does not work for file download pages. The extended page class have to be registered to click.xml.

3/10/2008

Click Framework + LiveValidation

Click controls provide JavaScript validation, but they are not easy to customize. Now I'm writing JavaScript validation framework for Click using LiveValidation. In the page class, ready the LivaValiator control like below:

Form form = new Form("form");
form.add(new TextField("name", true));
form.add(new PasswordField("password", true));
form.add(new Submit("login"));

addControl(new LivaValidator("validator", form));

In the page template, generates LiveValidation JavaScript code by the LiveValidator control:

<body>
  $form
  <script type="text/javascript">
    $validator
  </script>
</body>

We can also add customized validation rules by use of Validate.Custom.

3/09/2008

OVal: The simple validation framework for Java

OVal is the simple validation framework for Java. You can specify validation rules using annotations.

public class Person {
  @NotNull
  public String name;
}

Usage:

Validator v = new Validator();

Person p = new Person();
for(ConstraintViolation error: v.validate(p)){
  System.out.println(error.getMessage());
}

OVal can switch validation rules by profiles.

public class Person {
  @NotNull(profiles={"profile1"})
  public String name;
  
  @NotNull(profiles={"profile1", "profile2"})
  public String email;
}

Switch profiles like following:

// Enable all profiles
v.enableAllProfiles();
// Enable a specified profile
v.enableProfile("profile1");

// Disable all profiles
v.disableAllProfiles();
// Disable a specified profile
v.disableProfile("profile1");

2/21/2008

JSONIC - simple json encoder/decoder for java

JSONIC is a simple JSON encoder / decoder for Java made in Japan. We can get JSONIC from http://sourceforge.jp/projects/jsonic/files/. The use of JSONIC is very easy.

import net.arnx.jsonic.JSON;

// POJO to JSON
String text = JSON.encode(new Hoge());

// JSON to POJO
Hoge hoge = JSON.decode(text, Hoge.class);

JSONIC can handle POJO's public fields as property well and it also encode / decode java.util.Map and java.util.List.

I recommend JSONIC if you have to handle JSON in Java. It would be a best choice.

The First Seasar2 Example

At first, I show the very simple example to use S2Container. I created following 3 files into "jp.sf.amateras.seasar.example" package.

example.dicon

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE components PUBLIC "-//SEASAR2.1//DTD S2Container//EN"
          "http://www.seasar.org/dtd/components24.dtd">
<components>
  <component class="java.util.ArrayList" name="list">
    <initMethod name="add"><arg>"Naoki Takezoe"</arg></initMethod>
  </component>
</components>
<components>
  <component class="jp.sf.amateras.seasar.example.Hello" name="hello">
    <property name="target">list</property>
  </component>
</components>

Hello.java

package jp.sf.amateras.seasar.example;
import java.util.List;

public class Hello {
 private List target;
 public void setTarget(List target){
   this.target = target;
 }
 public void sayHello(){
   for(int i=0;i<target.size();i++){
     System.out.println("Hello, " + target.get(i));
   }
 }
}

Main.java

package jp.sf.amateras.seasar.example;
import org.seasar.framework.container.S2Container;
import org.seasar.framework.container.factory.S2ContainerFactory;

public class Main {
 public static void main(String[] args){
   S2Container container = S2ContainerFactory.create(
              "jp/sf/amateras/seasar/example/example.dicon");
   Hello hello = (Hello)container.getComponent("hello");
   hello.sayHello();
 }
}

Run the "Main" class as a Java application, it displays "Hello, Naoki Takezoe".

2/12/2008

S2Dao: 2-Way SQL

S2Dao can assemble dynamic query using SQL comment. For example:

@Sql("SELECT * FROM emp WHERE empno = /*empno*/7788")
@Arguments("empno")
public Emp selectEmpByEmpNo(int empNo);

/*empno*/ replaces the given argument and 7788 is removed by S2Dao at runtime. We can execute this SQL without no modification with the database client software such as psql. This solutuion is called "2-Way SQL" in S2Dao.

We can also use IF..ELSE statement as SQL comment.

/*IF hoge != null*/hoge = /*hoge*/'abc'/*END*/

And see the following example. If all conditions are false, S2Dao ignores /*BEGIN*/ ... /*END*/ block. So WHERE phrase is removed when it's not needed.

/*BEGIN*/WHERE
  /*IF job != null*/job = /*job*/'CLERK'/*END*/
  /*IF deptno != null*/AND deptno = /*deptno*/20/*END*/
/*END*/

Again, these SQL can be executed with database client software with no modifications. 2-Way SQL makes possible to test SQL easily.

2/11/2008

S2Dao: The most powerfull database access framework

S2Dao is a database access framework based on the Seasar2 and AOP solution. Today, I introduce this great framework to you.

S2Dao makes DAO from Java interface using AOP at runtime. We have to write only Java interface such as:

@S2Dao(bean=UserInfo.class)
public interface UserInfoDao {
  public List<UserInfo> selectAllUserInfos();
  public void insertUserInfo(UserInfo userInfo);
  public void updateUserInfo(UserInfo userInfo);
  public void deleteUserInfo(UserInfo userInfo);
}

SQLs are generated automatically by the entity definition (which is specified by @S2Dao) and DAO method names. So we don't have to write SQL in simple cases such as CRUD to the single table.

Of course, we can use complex SQL instead of auto generated SQL. We can specify WHERE and ORDER BY using @Query:

@Query("DEPTID=? ORDER BY EMPNO")
public List<UserInfo> selectUserInfoByDeptId(int deptId);

And using @Sql, we can specify all parts of SQL:

@Sql("SELECT COUNT(*) FROM USERINFO")
public int getCount();

These are parts of S2Dao great features. If we have to use complex and large SQL, we can write it as an external SQL file named "classname_methodname.sql" and S2Dao also support dynamic query using SQL comment. I will talk about them as another entries.