Package rife.database

Class DbRowProcessor

java.lang.Object
rife.database.DbRowProcessor
All Implemented Interfaces:
Cloneable
Direct Known Subclasses:
DbBeanFetcher
public abstract class DbRowProcessor extends Object implements Cloneable
This abstract base class should be used to implement classes that process one row in a database query result set. The fetch method of a DbQueryManager requires an instance of a DbRowProcessor and calls its processRow method each time it is called.

The DbRowProcessor instance can then work with the result set and extract all needed data. It is free to implement any logic to be able to return the retrieved data in an acceptable form to the user.

A class that extends DbRowProcessor can for example take a Template instance as the argument of its constructor and progressively fill in each resulting row in an HTML table. This, without having to maintain the query results in memory to be able to provide it to a separate method which is responsible for the handling of the output. Using a DbRowProcessor thus allows for perfect separation and abstraction of result processing without having to be burdened with possible large memory usage or large object allocation.

Since:
1.0
See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    DbRowProcessor()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    Object
    clone()
    Simply clones the instance with the default clone method since this class contains no object member variables.
    abstract boolean
    processRow(ResultSet resultSet)
    This method has to be implemented by each class that extends the DbRowProcessor class.
    final boolean
    wasSuccessful()
    Indicates whether the processing of the row was successful.

    Methods inherited from class java.lang.Object

    equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • DbRowProcessor

      public DbRowProcessor()

  • Method Details

    • processRow

      public abstract boolean processRow(ResultSet resultSet) throws SQLException
      This method has to be implemented by each class that extends the DbRowProcessor class. It has to contain all the logic that should be executed for each row of a result set.
      Parameters:
      resultSet - the ResultSet instance that was provided to the DbQueryManager's fetch method.
      Returns:
      true if the processing is considered successful; or

      false if the processing is considered failed.

      Note: this return value is purely indicative and unless the user does checks with the wasSuccessful() method, it will have no influence on anything.

      Throws:
      SQLException - when a database error occurs, it's thus not necessary to catch all the possible SQLExceptions inside this method. They'll be caught higher up and be transformed in DatabaseExceptions.
      Since:
      1.0
      See Also:

    • wasSuccessful

      public final boolean wasSuccessful()
      Indicates whether the processing of the row was successful.
      Returns:
      true if the processing was successful; or

      false if the processing was unsuccessful.

      Since:
      1.0

    • clone

      public Object clone()
      Simply clones the instance with the default clone method since this class contains no object member variables.
      Overrides:
      clone in class Object
      Since:
      1.0