org.wso2.extension.siddhi.store.rdbms.util

Class RDBMSTableUtils

java.lang.Object

org.wso2.extension.siddhi.store.rdbms.util.RDBMSTableUtils

public class RDBMSTableUtils
extends Object

Class which holds the utility methods which are used by various units in the RDBMS Event Table implementation.

Method Summary

Modifier and Type	Method and Description
static void	cleanupConnection(ResultSet rs, Statement stmt, Connection conn) Method which can be used to clear up and ephemeral SQL connectivity artifacts.
static int	enumerateUpdateSetEntries(Map<String,org.wso2.siddhi.core.util.collection.operator.CompiledExpression> updateSetExpressions, PreparedStatement stmt, Map<String,Object> updateSetMap)
static String	flattenAnnotatedElements(List<org.wso2.siddhi.query.api.annotation.Element> elements) Util method used to convert a list of elements in an annotation to a comma-separated string.
static String	formatQueryWithCondition(String query, String condition) Method for replacing the placeholder for conditions with the SQL Where clause and the actual condition.
static boolean	isEmpty(String field) Utility method which can be used to check if a given string instance is null or empty.
static RDBMSQueryConfigurationEntry	lookupCurrentQueryConfigurationEntry(DataSource ds, org.wso2.siddhi.core.util.config.ConfigReader configReader) Isolates a particular RDBMS query configuration entry which matches the retrieved DB metadata.
static Map<String,Object>	lookupDatabaseInfo(DataSource ds) Utility method used for looking up DB metadata information from a given datasource.
static void	populateStatementWithSingleElement(PreparedStatement stmt, int ordinal, org.wso2.siddhi.query.api.definition.Attribute.Type type, Object value) Util method which is used to populate a PreparedStatement instance with a single element.
static Map<String,String>	processFieldLengths(String fieldInfo) Read and return all string field lengths given in an RDBMS event table definition.
static List<String[]>	processKeyValuePairs(String annotationString) Converts a flat string of key/value pairs (e.g.
static void	resolveCondition(PreparedStatement stmt, RDBMSCompiledCondition compiledCondition, Map<String,Object> conditionParameterMap, int seed) Util method used throughout the RDBMS Event Table implementation which accepts a compiled condition (from compile-time) and uses values from the runtime to populate the given PreparedStatement.
static void	rollbackConnection(Connection conn) Method which is used to roll back a DB connection (e.g.
static void	validateAnnotation(org.wso2.siddhi.query.api.annotation.Annotation annotation) Util method which validates the elements from an annotation to verify that they comply to the accepted standards.

Methods inherited from class java.lang.Object

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

Method Detail

isEmpty

public static boolean isEmpty(String field)

Utility method which can be used to check if a given string instance is null or empty.

Parameters:

field - the string instance to be checked.

Returns:

true if the field is null or empty.

cleanupConnection

public static void cleanupConnection(ResultSet rs,
                                     Statement stmt,
                                     Connection conn)

Method which can be used to clear up and ephemeral SQL connectivity artifacts.

Parameters:

rs - ResultSet instance (can be null)

stmt - PreparedStatement instance (can be null)

conn - Connection instance (can be null)

rollbackConnection

public static void rollbackConnection(Connection conn)

Method which is used to roll back a DB connection (e.g. in case of any errors)

Parameters:

conn - the Connection instance to be rolled back (can be null).

resolveCondition

public static void resolveCondition(PreparedStatement stmt,
                                    RDBMSCompiledCondition compiledCondition,
                                    Map<String,Object> conditionParameterMap,
                                    int seed)
                             throws SQLException

Util method used throughout the RDBMS Event Table implementation which accepts a compiled condition (from compile-time) and uses values from the runtime to populate the given PreparedStatement.

Parameters:

stmt - the PreparedStatement instance which has already been build with '?' parameters to be filled.

compiledCondition - the compiled condition which was built during compile time and now is being provided by the Siddhi runtime.

conditionParameterMap - the map which contains the runtime value(s) for the condition.

seed - the integer factor by which the ordinal count will be incremented when populating the PreparedStatement.

Throws:

SQLException - in the unlikely case where there are errors when setting values to the statement (e.g. type mismatches)

enumerateUpdateSetEntries

public static int enumerateUpdateSetEntries(Map<String,org.wso2.siddhi.core.util.collection.operator.CompiledExpression> updateSetExpressions,
                                            PreparedStatement stmt,
                                            Map<String,Object> updateSetMap)
                                     throws SQLException

Throws:

SQLException

populateStatementWithSingleElement

public static void populateStatementWithSingleElement(PreparedStatement stmt,
                                                      int ordinal,
                                                      org.wso2.siddhi.query.api.definition.Attribute.Type type,
                                                      Object value)
                                               throws SQLException

Util method which is used to populate a PreparedStatement instance with a single element.

Parameters:

stmt - the statement to which the element should be set.

ordinal - the ordinal of the element in the statement (its place in a potential list of places).

type - the type of the element to be set, adheres to Attribute.Type.

value - the value of the element.

Throws:

SQLException - if there are issues when the element is being set.

validateAnnotation

public static void validateAnnotation(org.wso2.siddhi.query.api.annotation.Annotation annotation)

Util method which validates the elements from an annotation to verify that they comply to the accepted standards.

Parameters:

annotation - the annotation to be validated.

flattenAnnotatedElements

public static String flattenAnnotatedElements(List<org.wso2.siddhi.query.api.annotation.Element> elements)

Util method used to convert a list of elements in an annotation to a comma-separated string.

Parameters:

elements - the list of annotation elements.

Returns:

a comma-separated string of all elements in the list.

processFieldLengths

public static Map<String,String> processFieldLengths(String fieldInfo)

Read and return all string field lengths given in an RDBMS event table definition.

Parameters:

fieldInfo - the field length annotation from the "@Store" definition (can be empty).

Returns:

a map of fields and their specified sizes.

processKeyValuePairs

public static List<String[]> processKeyValuePairs(String annotationString)

Converts a flat string of key/value pairs (e.g. from an annotation) into a list of pairs. Used String[] since Java does not offer tuples.

Parameters:

annotationString - the comma-separated string of key/value pairs.

Returns:

a list processed and validated pairs.

formatQueryWithCondition

public static String formatQueryWithCondition(String query,
                                              String condition)

Method for replacing the placeholder for conditions with the SQL Where clause and the actual condition.

Parameters:

query - the SQL query in string format, with the "{{CONDITION}}" placeholder present.

condition - the actual condition (originating from the ConditionVisitor).

Returns:

the formatted string.

lookupDatabaseInfo

public static Map<String,Object> lookupDatabaseInfo(DataSource ds)

Utility method used for looking up DB metadata information from a given datasource.

Parameters:

ds - the datasource from which the metadata needs to be looked up.

Returns:

a list of DB metadata.

lookupCurrentQueryConfigurationEntry

public static RDBMSQueryConfigurationEntry lookupCurrentQueryConfigurationEntry(DataSource ds,
                                                                                org.wso2.siddhi.core.util.config.ConfigReader configReader)
                                                                         throws org.wso2.siddhi.core.exception.CannotLoadConfigurationException

Isolates a particular RDBMS query configuration entry which matches the retrieved DB metadata.

Parameters:

ds - the datasource against which the entry should be matched.

Returns:

the matching RDBMS query configuration entry.

Throws:

org.wso2.siddhi.core.exception.CannotLoadConfigurationException - if the configuration cannot be loaded.