net.as_development.asdk.db_service.impl

Class DBQuery<TEntity extends IEntity>

java.lang.Object

net.as_development.asdk.db_service.impl.DBQuery<TEntity>

All Implemented Interfaces:

IDBQuery<TEntity>, IDBBackendQuery

public class DBQuery<TEntity extends IEntity>
extends Object
implements IDBQuery<TEntity>, IDBBackendQuery

An implementation for the interface IDBQuery. One example: YourDbEntity aEntity = new YourDbEntity (); IDB iDb = iDbPool.getDbForPersistenceUnit (); // If this is called the first time (you must not track that outside !) // it creates a new query ... // If its called the second time it reuses the internal cached query object. // But it does not compile these query ! IDBQuery iQuery = iDb.prepareQuery ("YourQueryId"); // Then you can define your query attributes and values. // If you call it the first time ... you do two things at the same time: // a ) you define the structure of the query by adding new attribute names // b ) you define the first set of query values by setting new values // // If you call it the second time ... // a') we check if your attribute is still known on that query // - in case it's not ... an exception is thrown // - otherwise ... // b') you define the set of query values by setting new values // for existing attributes here iQuery.setQueryPart (0, EQueryPartBinding.E_AND, EQueryPartOperation.E_MATCH, "your_attribute", your_value); // If this is the first request for this query ... // it will be compiled and executed then. // If it is the second request for this query ... // it wont be compiled ... but executed. iDb.query(..., iQuery);

Constructor Summary

Constructors

Constructor and Description
DBQuery()

Method Summary

Modifier and Type	Method and Description
void	bindToQueryTemplate(DBQueryTemplate<TEntity> aTemplate) bind this query instance to it's template where all meta information exists.
String	getId()
int	getPartCount()
QueryPartValue[]	getQueryParts() provides read access to the different parts of this query.
DBQueryTemplate<TEntity>	getTemplate()
void	setQueryPart(int nPosition, EQueryPartBinding eBinding, EQueryPartOperation eOperation, String sAttribute, Object aValue) define one part of the query ...

Methods inherited from class java.lang.Object

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

Constructor Detail

DBQuery

public DBQuery()

Method Detail

bindToQueryTemplate

public void bindToQueryTemplate(DBQueryTemplate<TEntity> aTemplate)

bind this query instance to it's template where all meta information exists. Those meta information knows nearly everything about the bound entity class where this query is good for. Note Those template will might be cached elsewhere and referenced by more then one DBQuery instance. DONT use it in writable mode. Use it READONLY. On the other side ... after query template was compiled first time it throws exceptions in case you try to call any set method on it ... so - try it :-)

Parameters:

aTemplate - [IN] the template where this query is bound to.

getTemplate

public DBQueryTemplate<TEntity> getTemplate()
                                     throws Exception

Returns:

the bound query template of this query. Used e.g. by the DB implementation to cache or compile the query template on the fly...

Throws:

Exception

getId

public String getId()
             throws Exception

Specified by:

getId in interface IDBQuery<TEntity extends IEntity>

Specified by:

getId in interface IDBBackendQuery

Returns:

the internal ID of this query. Those ID was define by YOU ... because you have to create queries by calling IDB.prepareQuery(sID) :-)

Throws:

Exception

setQueryPart

public void setQueryPart(int nPosition,
                         EQueryPartBinding eBinding,
                         EQueryPartOperation eOperation,
                         String sAttribute,
                         Object aValue)
                  throws Exception

Description copied from interface: IDBQuery

define one part of the query ... or set a new value there.

Specified by:

setQueryPart in interface IDBQuery<TEntity extends IEntity>

Parameters:

nPosition - [IN] the position of that part within the query. Must start at 0.

eBinding - [IN] define the boolean operator (and/or) against the part placed at nPosition-1. Will be ignored if nPosition==0.

eOperation - [IN] define the operation used by this part (==, like, between ...)

sAttribute - [IN] the name of the attribute to be checked here.

aValue - [IN] the search value itself. Note For the given value there exists some conditions ... a) if eOperation=like it must be from type String. b) if eOperation=between it must be from type BetweenQueryRange.

Throws:

Exception

getQueryParts

public QueryPartValue[] getQueryParts()
                               throws Exception

Description copied from interface: IDBBackendQuery

provides read access to the different parts of this query. Order within that list is important. On creating the query the 'user' decided in which order those parts has to be added ... and now we have respect that too. Otherwise e.g. logical operator like 'and'/'or' wont work as expected. So please start with the first part at position 0 .-)

Specified by:

getQueryParts in interface IDBBackendQuery

Throws:

Exception

getPartCount

public int getPartCount()
                 throws Exception

Throws:

Exception