org.sqlproc.engine
Class SqlEngineLoader

java.lang.Object
  org.sqlproc.engine.SqlEngineLoader

All Implemented Interfaces:

SqlEngineFactory

public class SqlEngineLoader
extends Object
implements SqlEngineFactory

The helper class for the META SQL statements and mapping rules parsing. These statements and rules are taken from the Properties.
The purpose of this class is to load and analyze (=parse) the META SQL statements and mapping rules located in the properties repository. The standard properties repository is the external properties file with the name queries.properties.

This is rather a low level helper class. For more simple approach please see SqlSimpleFactory

All the properties with the key QRY_... are parsed as the META SQL queries using the ANTLR based grammar.
All the properties with the key CRUD_... are parsed as the META SQL CRUD statements using the ANTLR based grammar.
All the properties with the key OUT_... are parsed as the mapping rules using the ANTLR based grammar.
A pair of the META SQL statement and the (optional) mapping rule forms one named SQL Engine instance.
All the properties with the key SET_... are taken as the optional features used in the process of the SQL query/statement generation and execution.

In the process of ANTLR based parsing different kinds of incorrect stuff can cause the SqlEngineException to be raised.

In the process of the META SQL statements and mapping rules parsing the input/output values META types have to be established. For this purpose a factory class responsible for these META types construction has to be supplied.

To initialize the SqlEngineLoader, Spring DI configuration can be utilized, like the next one:

 <beans ...>
   ...
   <bean id="typeFactory" class="org.sqlproc.engine.jdbc.type.JdbcTypeFactory" factory-method="getInstance" />
 
   <bean id="sqlQueries" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
     <property name="location">
       <value>classpath:queries.properties</value>
     </property>
   </bean>
   
   <bean id="sqlLoader" class="org.sqlproc.engine.SqlEngineLoader">
     <constructor-arg ref="sqlQueries" />
     <constructor-arg ref="typeFactory" />
   </bean>
 </beans>
 

and use the next code to obtain an instance of the SQL Query engine

 SqlQueryEngine sqlEngine = sqlLoader.getQueryEngine("ALL");
 

or the next code to obtain an instance of the SQL CRUD engine

 SqlCrudEngine sqlEngine = sqlLoader.getCrudEngine("ALL");
 

Another possibility is to utilize SqlPropertiesLoader.

 SqlPropertiesLoader loader = new SqlPropertiesLoader("queries.properties", this.getClass());
 SqlEngineLoader sqlLoader = new SqlEngineLoader(loader.getProperties(), JdbcTypeFactory.getInstance());
 SqlEngine sqlEngine = sqlLoader.getQueryEngine("ALL");
 

For more info please see the Reference Guide or the tutorials.

Author:

Vladimir Hudec

Field Summary

private SqlTypeFactory	composedTypeFactory
private static String	CRUD_PREFIX
private Map<String,String>	cruds The collection of named META SQL CRUD statements.
private Map<String,SqlEngine>	engines The collection of named SQL Engine (the primary SQL Processor class) instances.
private Map<String,Object>	features The collection of the SQL Processor optional features.
private Map<String,String>	fields The collection of named explicitly defined mapping rules.
private static String	FIELDS_REFERENCE
private static String	INPUT_MAPPING_PREFIX
private static int	lCRUD_PREFIX
private static int	lFIELDS_REFERENCE
private static int	lINPUT_MAPPING_PREFIX
protected org.slf4j.Logger	logger The internal slf4j logger.
private static int	lOUTPUT_MAPPING_PREFIX
private static int	lQUERY_PREFIX
private static int	lSET_PREFIX
private static String	OUTPUT_MAPPING_PREFIX
private static String	QUERY_PREFIX
private static String	SET_PREFIX
private Map<String,String>	sqls The collection of named META SQL queries.

Constructor Summary

SqlEngineLoader(Properties props, SqlTypeFactory typeFactory)
Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features.

SqlEngineLoader(Properties props, SqlTypeFactory typeFactory, String filter)
Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features.

SqlEngineLoader(Properties props, SqlTypeFactory typeFactory, String filter, SqlMonitorFactory monitorFactory)
Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features.

SqlEngineLoader(Properties props, SqlTypeFactory typeFactory, String filter, SqlMonitorFactory monitorFactory, List<SqlInternalType> customTypes, String... selectQueries)
Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features.

SqlEngineLoader(Properties props, SqlTypeFactory typeFactory, String filter, SqlMonitorFactory monitorFactory, String... selectQueries)
Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features.

Method Summary

SqlCrudEngine	getCrudEngine(String name) Returns the named SQL CRUD Engine instance (the primary SQL Processor class).
String	getMappingRule(String name) Returns the named mapping rule.
String	getMetaSql(String name) Returns the named META SQL query/statement.
Collection<String>	getNames() Returns the collection of names of all initialized/constructed SQL Engine instances.
SqlQueryEngine	getQueryEngine(String name) Returns the named SQL Query Engine instance (the primary SQL Processor class).

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected final org.slf4j.Logger logger

The internal slf4j logger.

SET_PREFIX

private static final String SET_PREFIX

See Also:

Constant Field Values

lSET_PREFIX

private static final int lSET_PREFIX

FIELDS_REFERENCE

private static final String FIELDS_REFERENCE

See Also:

Constant Field Values

lFIELDS_REFERENCE

private static final int lFIELDS_REFERENCE

QUERY_PREFIX

private static final String QUERY_PREFIX

See Also:

Constant Field Values

lQUERY_PREFIX

private static final int lQUERY_PREFIX

INPUT_MAPPING_PREFIX

private static final String INPUT_MAPPING_PREFIX

See Also:

Constant Field Values

lINPUT_MAPPING_PREFIX

private static final int lINPUT_MAPPING_PREFIX

OUTPUT_MAPPING_PREFIX

private static final String OUTPUT_MAPPING_PREFIX

See Also:

Constant Field Values

lOUTPUT_MAPPING_PREFIX

private static final int lOUTPUT_MAPPING_PREFIX

CRUD_PREFIX

private static final String CRUD_PREFIX

See Also:

Constant Field Values

lCRUD_PREFIX

private static final int lCRUD_PREFIX

composedTypeFactory

private SqlTypeFactory composedTypeFactory

engines

private Map<String,SqlEngine> engines

The collection of named SQL Engine (the primary SQL Processor class) instances.

sqls

private Map<String,String> sqls

The collection of named META SQL queries.

cruds

private Map<String,String> cruds

The collection of named META SQL CRUD statements.

fields

private Map<String,String> fields

The collection of named explicitly defined mapping rules.

features

private Map<String,Object> features

The collection of the SQL Processor optional features.

Constructor Detail

SqlEngineLoader

public SqlEngineLoader(Properties props,
                       SqlTypeFactory typeFactory)
                throws SqlEngineException

Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features. During the instance construction all the statements are parsed and the collection of named SQL Engine instances is established. Later these instances are used for the SQL queries/statements execution. For the purpose of the META types construction (located inside the META SQL statements and mapping rules) a factory instance has to be supplied.

Parameters:

props - the collection of META SQL statements, mapping rules and optional features located in the properties repository

typeFactory - the factory for the META types construction

Throws:

SqlEngineException - mainly in the case the provided statements or rules are not compliant with the ANTLR based grammar

SqlEngineLoader

public SqlEngineLoader(Properties props,
                       SqlTypeFactory typeFactory,
                       String filter)
                throws SqlEngineException

Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features. During the instance construction all the statements are parsed and the collection of named SQL Engine instances is established. Later these instances are used for the SQL queries/statements execution. For the purpose of the META types construction (located inside the META SQL statements and mapping rules) a factory instance has to be supplied.

Parameters:

props - the collection of META SQL statements, mapping rules and optional features

typeFactory - the factory for the META types construction

filter - the properties name prefix to filter the META SQL statements, mapping rules and optional features

Throws:

SqlEngineException - mainly in the case the provided statements or rules are not compliant with the ANTLR based grammar

SqlEngineLoader

public SqlEngineLoader(Properties props,
                       SqlTypeFactory typeFactory,
                       String filter,
                       SqlMonitorFactory monitorFactory)
                throws SqlEngineException

Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features. During the instance construction all the statements are parsed and the collection of named SQL Engine instances is established. Later these instances are used for the SQL queries/statements execution. For the purpose of the META types construction (located inside the META SQL statements and mapping rules) a factory instance has to be supplied. Every instance of the SQL Engine is accompanied with the SQL Monitor for the runtime statistics gathering. For the creation of these monitors the SQL Monitor Factory can be used.

Parameters:

props - the collection of META SQL statements, mapping rules and optional features

typeFactory - the factory for the META types construction

filter - the properties name prefix to filter the META SQL statements, mapping rules and optional features

monitorFactory - the monitor factory used in the process of the SQL Monitor instances creation

Throws:

SqlEngineException - mainly in the case the provided statements or rules are not compliant with the ANTLR based grammar

SqlEngineLoader

public SqlEngineLoader(Properties props,
                       SqlTypeFactory typeFactory,
                       String filter,
                       SqlMonitorFactory monitorFactory,
                       String... selectQueries)

Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features. During the instance construction all the statements are parsed and the collection of named SQL Engine instances is established. Later these instances are used for the SQL queries/statements execution. For the purpose of the META types construction (located inside the META SQL statements and mapping rules) a factory instance has to be supplied. Every instance of the SQL Engine is accompanied with the SQL Monitor for the runtime statistics gathering. For the creation of these monitors the SQL Monitor Factory can be used.

Parameters:

props - the collection of META SQL statements, mapping rules and optional features

typeFactory - the factory for the META types construction

filter - the properties name prefix to filter the META SQL statements, mapping rules and optional features

monitorFactory - the monitor factory used in the process of the SQL Monitor instances creation

selectQueries - only statements and rules with the names in this set are picked up from the properties repository

Throws:

SqlEngineException - mainly in the case the provided statements or rules are not compliant with the ANTLR based grammar

SqlEngineLoader

public SqlEngineLoader(Properties props,
                       SqlTypeFactory typeFactory,
                       String filter,
                       SqlMonitorFactory monitorFactory,
                       List<SqlInternalType> customTypes,
                       String... selectQueries)
                throws SqlEngineException

Creates a new instance of the SqlEngineLoader from the properties repository (which is in fact a collection of the META SQL statements, mapping rules and optional features. During the instance construction all the statements are parsed and the collection of named SQL Engine instances is established. Later these instances are used for the SQL queries/statements execution. For the purpose of the META types construction (located inside the META SQL statements and mapping rules) a factory instance has to be supplied. Every instance of the SQL Engine is accompanied with the SQL Monitor for the runtime statistics gathering. For the creation of these monitors the SQL Monitor Factory can be used.

Parameters:

props - the collection of META SQL statements, mapping rules and optional features

typeFactory - the factory for the META types construction

filter - the properties name prefix to filter the META SQL statements, mapping rules and optional features

monitorFactory - the monitor factory used in the process of the SQL Monitor instances creation

customTypes - the custom META types

selectQueries - only statements and rules with the names in this set are picked up from the properties repository

Throws:

SqlEngineException - mainly in the case the provided statements or rules are not compliant with the ANTLR based grammar

Method Detail

getNames

public Collection<String> getNames()

Returns the collection of names of all initialized/constructed SQL Engine instances.

Returns:

Collection of all initialized SQL Engine instances' names

getMetaSql

public String getMetaSql(String name)

Returns the named META SQL query/statement.

Parameters:

name - the name of the required META SQL query/statement

Returns:

the META SQL query/statement

getMappingRule

public String getMappingRule(String name)

Returns the named mapping rule.

Parameters:

name - the name of the required mapping rule

Returns:

the mapping rule

getQueryEngine

public SqlQueryEngine getQueryEngine(String name)

Returns the named SQL Query Engine instance (the primary SQL Processor class).

Specified by:

getQueryEngine in interface SqlEngineFactory

Parameters:

name - the name of the required SQL Query Engine instance

Returns:

the SQL Engine instance

getCrudEngine

public SqlCrudEngine getCrudEngine(String name)

Returns the named SQL CRUD Engine instance (the primary SQL Processor class).

Specified by:

getCrudEngine in interface SqlEngineFactory

Parameters:

name - the name of the required SQL CRUD Engine instance

Returns:

the SQL Engine instance