jobmatch.data
Class EmployerQuery

jobmatch.data.EmployerQuery

public final class EmployerQuery

EmployerQuery is used to query the Employer table in the database.
It returns objects of type EmployerDO.

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: 1.6 $

Constructor Summary

EmployerQuery()
Public constructor.

Method Summary

void	addOrderByAdress() Add Adress to the ORDER BY clause.
void	addOrderByAdress(boolean direction_flag) Add Adress to the ORDER BY clause.
void	addOrderByName() Add Name to the ORDER BY clause.
void	addOrderByName(boolean direction_flag) Add Name 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.
EmployerBDO[]	getBDOArray() Return array of BDOs constructed from ResultSet returned by query.
EmployerDO[]	getDOArray() Return array of DOs constructed from ResultSet returned by query.
EmployerBDO	getNextBDO() Return successive BDOs from array built from ResultSet returned by query.
EmployerDO	getNextDO() Return successive DOs from array built from ResultSet returned by query.
jobmatch.data.QueryBuilder	getQueryBuilder() Returns the QueryBuilder that this EmployerQuery 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	setQueryAdress(AdressDO x) Set the Adress to query
void	setQueryAdress(AdressDO x, boolean exact) Set the Adress to query.
void	setQueryHandle(String handle) Set the object handle to query.
void	setQueryName(String x) Set the Name to query
void	setQueryName(String x, boolean exact) Set the Name to query.
void	setQueryOId(jobmatch.data.ObjectId oid) Set the OID to query.

Constructor Detail

EmployerQuery

public EmployerQuery()

Public constructor.

Method Detail

hitDatabase

public void hitDatabase()

getDOArray

public EmployerDO[] 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 EmployerDO 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 EmployerBDO[] 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 EmployerBDO 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 Employer 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.

setQueryName

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

Set the Name to query.

Parameters:

x - The Name of the Employer to query.

exact - to use matches or not

Throws:

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

setQueryName

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

Set the Name to query

Parameters:

x - The Name of the Employer to query.

Throws:

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

addOrderByName

public void addOrderByName(boolean direction_flag)

Add Name to the ORDER BY clause.

Parameters:

direction_flag - True for ascending order, false for descending

addOrderByName

public void addOrderByName()

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

setQueryAdress

public void setQueryAdress(AdressDO x,
                           boolean exact)
                    throws jobmatch.data.DataObjectException,
                           jobmatch.data.QueryException

Set the Adress to query.

Parameters:

x - The Adress of the Employer to query.

exact - to use matches or not

Throws:

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

setQueryAdress

public void setQueryAdress(AdressDO x)
                    throws jobmatch.data.DataObjectException,
                           jobmatch.data.QueryException

Set the Adress to query

Parameters:

x - The Adress of the Employer to query.

Throws:

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

addOrderByAdress

public void addOrderByAdress(boolean direction_flag)

Add Adress to the ORDER BY clause.

Parameters:

direction_flag - True for ascending order, false for descending

addOrderByAdress

public void addOrderByAdress()

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

getQueryBuilder

public jobmatch.data.QueryBuilder getQueryBuilder()

Returns the QueryBuilder that this EmployerQuery uses to construct and execute database queries. EmployerQuery.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 EmployerQuery, the application developer does not call getQueryBuilder, then EmployerQuery.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 EmployerQuery 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