Hibernate Filter Example

Hibernate Filter

I am going to describe very basic thing about hibernate data filter for pre-define fetching of data.

Just consider any application,in which on every page or listing we only fetch data those are not deleted, i.e isDeleted=false.

We fetch such data by writting criteria or HQL using WHERE clause or Criteria Restrictions.

But at the same time we have to apply  this on associated child collection then we Iterate on the dependent association  to make sure that the record is deleted or not, and then it becomes very costly.

To override such kind of problem we can use hibernate filter and as per our need we can enable or disable it.

See below filter configuration

HBM configuration

<hibernate-mapping>

<class name="Users" table="userdetails" >

<filter name="deleteCheck" condition="isDeleted = :deleteFlag"/>

</class>   

 <filter-def name=" deleteCheck ">

   <filter-param name=" deleteFlag" type="boolean"/>

 </filter-def>

</hibernate-mapping>

Annotation Configuration

@javax.persistence.Entity(name="userdetails")

@FilterDef(name="deleteCheck",parameters=@ParamDef( name="deleteFlag", type="boolean" ))

@Filter(name="deleteCheck", condition="isDeleted=:deleteFlag")

public class User implements Serializable {

     

      private static final long serialVersionUID = 1L;

     

      private Integer userId;

     

      private String name;

     

      private String address;

     

      private Boolean isDeleted;

     

           

      //Setter getter method

}

Applying Filter

public List getUsers()

      {

            List userlist=null;

            Session session=HibernateSessionFactory.getSession();

            session.enableFilter("deleteCheck").setParameter("deleteFlag",true);

//session.disableFilter("deleteCheck");

            Criteria crit=session.createCriteria(User.class);

            userlist=crit.list();

            session.flush();

            session.close();

System.out.println(userList.size()+" user records");

            return userlist;

      }

It will automatically filter the data according to your filter param there is no need to do anything additional.

@Note: We can also apply this filter on collections or association as follows

For more details on Hibernate Filter Click here

String Annon Check Example

Annon means two words having same characters and same length.

Same characters means both words made of a common set of characters.

i.e teacher and cheater both words have same length and same set of characters, so we can say such types of string or word as Annon String or Annon word.

For more details see below written code to check that two string are Anon or not.

public void testAnnon()

      {

           String str1="teacher";

           String str2="cheater";

 

            char[]ch1=str1.toCharArray();

            char[] ch2=str2.toCharArray();

            Arrays.sort(ch1);

            Arrays.sort(ch2);

           

            boolean  flag=Arrays.equals(ch1, ch2);

            if(flag)

            {

                  System.out.println("Given strings are annon");

            }

            else

            {

                  System.out.println("Given strings are not annon");

            }

      }