jobmatch.data
Class PictureQuery

jobmatch.data.PictureQuery

public final class PictureQuery

PictureQuery is used to query the Picture table in the database.
It returns objects of type PictureDO.

General usage:

In DODS: Create a Data Object named "Dog", and create an Attribute named "Name", and set that Attribute to "Can be queried." DODS will then generate the method DogQuery.setQueryName().

In your Business Layer, prepare the query:

             DogQuery dq = new DogQuery();
             dq.setQueryName("Rex")
             if ( Rex is a reserved name )
                 dq.requireUniqueInstance();
 

Then, get the query results one of two ways:

#1:

             String names = "";
             DogBDO[] dogs = dq.getBDOArray();
             for ( int i = 0; i < dogs.length; i++ ) {
                 names += dogs[i].getName() + " ";
             }
 

or #2:

             String names = "";
             DogBDO dog;
             while ( null != ( dog = dq.getNextBDO() ) ) {
                 names += dog.getName() + " ";
             }
 

Note: Methods getDOArray() and getNextDO() do exist, but they are not generally used in the Business or Presentation layers of an application. All access to the Data Layer (DO classes) should occur via the Business Layer (BDO classes). Only the Business Layer (BDO classes and classes extending them) should need to manipulate the Data Layer (DO classes). See also the comments in the BDO constructors.

Note: If requireUniqueInstance() was called, then getBDOArray() or getNextBDO() will throw an exception if more than one "Rex" was found.

Note: Results of the query will come from the Data Object cache if: - The cache is available. - Matches were found in the cache. - No other tables (Data Objects of other types) were involved in the query. This can happen if you extend the DogQuery class and you make calls to the QueryBuilder object to add SQL involving other tables. If any of these conditions is not true, then any results from the query will come from the database.

To reuse the query object, call:

             dq.reset();
 

Version:

$Revision: 1.2 $

Constructor Summary

PictureQuery()
Public constructor.

Method Summary

void	addOrderByMimeType() Add MimeType to the ORDER BY clause.
void	addOrderByMimeType(boolean direction_flag) Add MimeType to the ORDER BY clause.
void	closeParen() Place a closing parenthesis in the WHERE clause.
ResultSet	executeQuery(jobmatch.data.DBConnection conn) Method to query objects from the database.
PictureBDO[]	getBDOArray() Return array of BDOs constructed from ResultSet returned by query.
PictureDO[]	getDOArray() Return array of DOs constructed from ResultSet returned by query.
PictureBDO	getNextBDO() Return successive BDOs from array built from ResultSet returned by query.
PictureDO	getNextDO() Return successive DOs from array built from ResultSet returned by query.
jobmatch.data.QueryBuilder	getQueryBuilder() Returns the QueryBuilder that this PictureQuery uses to construct and execute database queries.
void	hitDatabase()
Object	next(ResultSet rs) WARNING! This method is disabled.
void	openParen() Place an open parenthesis in the WHERE clause.
void	or() Insert an OR between WHERE clauses.
void	requireUniqueInstance() Set "unique instance" assertion bit.
void	reset() Reset the query parameters.
void	setQueryHandle(String handle) Set the object handle to query.
void	setQueryMimeType(String x) Set the MimeType to query
void	setQueryMimeType(String x, boolean exact) Set the MimeType to query.
void	setQueryOId(jobmatch.data.ObjectId oid) Set the OID to query.

Constructor Detail

PictureQuery

public PictureQuery()

Public constructor.

Method Detail

hitDatabase

public void hitDatabase()

getDOArray

public PictureDO[] getDOArray()
                       throws jobmatch.data.DataObjectException,
                              jobmatch.data.NonUniqueQueryException

Return array of DOs constructed from ResultSet returned by query.

Throws:

jobmatch.data.DataObjectException - If a database access error occurs.

jobmatch.data.NonUniqueQueryException - If too many rows were found.

getNextDO

public PictureDO getNextDO()
                    throws jobmatch.data.DataObjectException,
                           jobmatch.data.NonUniqueQueryException

Return successive DOs from array built from ResultSet returned by query.

Throws:

jobmatch.data.DataObjectException - If a database access error occurs.

jobmatch.data.NonUniqueQueryException - If too many rows were found.

getBDOArray

public PictureBDO[] getBDOArray()
                         throws jobmatch.data.DataObjectException,
                                jobmatch.data.NonUniqueQueryException

Return array of BDOs constructed from ResultSet returned by query.

Throws:

jobmatch.data.DataObjectException - If a database access error occurs.

jobmatch.data.NonUniqueQueryException - If too many rows were found.

getNextBDO

public PictureBDO getNextBDO()
                      throws jobmatch.data.DataObjectException,
                             jobmatch.data.NonUniqueQueryException

Return successive BDOs from array built from ResultSet returned by query.

Throws:

jobmatch.data.DataObjectException - If a database access error occurs.

jobmatch.data.NonUniqueQueryException - If too many rows were found.

setQueryOId

public void setQueryOId(jobmatch.data.ObjectId oid)

Set the OID to query. WARNING! This method assumes that table Picture has a column named "oid". This method is called from the DO classes to retrieve an object by id.

Parameters:

oid - The object id to query.

setQueryHandle

public void setQueryHandle(String handle)
                    throws jobmatch.data.ObjectIdException

Set the object handle to query. This is a variant of setQueryOId().

Parameters:

handle - The string version of the id to query.

requireUniqueInstance

public void requireUniqueInstance()

Set "unique instance" assertion bit. The first call to the next() method will throw an exception if more than one object was found.

reset

public void reset()

Reset the query parameters.

executeQuery

public ResultSet executeQuery(jobmatch.data.DBConnection conn)
                       throws SQLException

Method to query objects from the database. The following call in runQuery() dbQuery.query( this ); causes the dbQuery object to invoke executeQuery()

Parameters:

conn - Handle to database connection.

Throws:

SQLException - If a database access error occurs.

next

public Object next(ResultSet rs)
            throws SQLException,
                   jobmatch.data.ObjectIdException

WARNING! This method is disabled. It's implementation is forced by the Query interface. This method is disabled for 2 reasons: 1) the getDOArray() and getNextDO() methods are better because they return DOs instead of JDBC objects. 2) the createExisting() method throws an exception that we cannot reasonably handle here, and that we cannot throw from here.

Parameters:

rs - JDBC result set from which the next object will be instantiated.

Throws:

SQLException - If a database access error occurs.

com.lutris.appserver.server.sql.ObjectIdException - If an invalid object id was queried from the database.

setQueryMimeType

public void setQueryMimeType(String x,
                             boolean exact)
                      throws jobmatch.data.DataObjectException,
                             jobmatch.data.QueryException

Set the MimeType to query.

Parameters:

x - The MimeType of the Picture to query.

exact - to use matches or not

Throws:

jobmatch.data.DataObjectException - If a database access error occurs.

setQueryMimeType

public void setQueryMimeType(String x)
                      throws jobmatch.data.DataObjectException,
                             jobmatch.data.QueryException

Set the MimeType to query

Parameters:

x - The MimeType of the Picture to query.

Throws:

jobmatch.data.DataObjectException - If a database access error occurs.

addOrderByMimeType

public void addOrderByMimeType(boolean direction_flag)

Add MimeType to the ORDER BY clause.

Parameters:

direction_flag - True for ascending order, false for descending

addOrderByMimeType

public void addOrderByMimeType()

Add MimeType to the ORDER BY clause. This convenience method assumes ascending order.

getQueryBuilder

public jobmatch.data.QueryBuilder getQueryBuilder()

Returns the QueryBuilder that this PictureQuery uses to construct and execute database queries. PictureQuery.setQueryXXX methods use the QueryBuilder to append SQL expressions to the "WHERE" clause to be executed. The QueryBuilder.addEndClause method. can be used to append freeform SQL expressions to the WHERE clause, e.g. "ORDER BY name". Notes regarding cache-enabled DO classes: DO classes can be cache-enabled. If when using a PictureQuery, the application developer does not call getQueryBuilder, then PictureQuery.setQueryXXX methods simply prune the DO cache and return the remaining results. However, a QueryBuilder builds SELECT statements for execution by the actual database, and never searches the built-in cache for the DO. So, if the DO class is cache-enabled, and getQueryBuilder is called, this PictureQuery object ignores the cache and hits the actual database.

or

public void or()

Insert an OR between WHERE clauses. Example: find all the persons named Bob or Robert: PersonQuery pq = new PersonQuery(); pq.setQueryFirstName( "Bob" ); pq.or(); pq.setQueryFirstName( "Robert" ); Note: Calls to setQueryXxx methods are implicitly ANDed together, so the following example will always return nothing: PersonQuery pq = new PersonQuery(); pq.setQueryFirstName( "Bob" ); // AND automatically inserted here. pq.setQueryFirstName( "Robert" );

See Also:

to construct more elaborate queries.

openParen

public void openParen()

Place an open parenthesis in the WHERE clause. Example usage: find all the Bobs and Roberts who are 5 or 50 years old: PersonQuery pq = new PersonQuery(); pq.openParen(); pq.setQueryFirstName( "Bob" ); pq.or(); pq.setQueryFirstName( "Robert" ); pq.closeParen(); // AND automatically inserted here. pq.openParen(); pq.setQueryAge( 5 ); pq.or(); pq.setQueryAge( 50 ); pq.closeParen();

See Also:

to construct more elaborate queries.

closeParen

public void closeParen()

Place a closing parenthesis in the WHERE clause.

See Also:

openParen