hydroScalingAPI.util.database
Class DataBaseEngine

java.lang.Object
  hydroScalingAPI.util.database.DataBaseEngine

public class DataBaseEngine
extends java.lang.Object

A Memory based implementation of a database engine. This was created to simplify the comunication between GUIs and Analysis Modules with the Gauges and Locations data in CUENCAS. However it is generic enough to handle other types of registers.

Author:

Ricardo Mantilla

Field Summary

static int	EQUAL_TO The value used to indicate a EQUAL_TO type of comparison
static int	GREATER_THAN The value used to indicate a GREATER_THAN type of comparison
static int	SMALLER_THAN The value used to indicate a SMALLER_THAN type of comparison

Constructor Summary

DataBaseEngine()
Creates a new instance of DataBaseEngine

Method Summary

void	addData(java.lang.String tableName, java.lang.String RegisterIndex, DB_Register Field) Adds an entry to one of the tables
void	addData(java.lang.String tableName, java.lang.String RegisterIndex, java.lang.Object[] Values) Adds an entry to one of the tables
void	addTable(java.lang.String tableName, java.lang.String[] Fields, java.lang.String[] Type) Adds a DB_Table into the database engine
DB_Register[]	compareFieldsTo(java.lang.String tableName, java.lang.String[] FieldName, java.lang.Object[] ValueToCompare, int[] ConditionToCheckFor) A more general search for registers in a table.
DB_Register[]	findRegister(java.lang.String tableName, java.lang.String[] FieldName, java.lang.Object[] ValueToMatch) Finds registers in a table that match a set of values criteria in several of its properties (e.g.
java.lang.Double	getMaxValue(java.lang.String tableName, java.lang.String FieldName) Returns the maximum value for a given "Numeric" Property in a given table
java.lang.Double	getMinValue(java.lang.String tableName, java.lang.String FieldName) Returns the minimum value for a given "Numeric" Property in a given table
DB_Register	getRegisterByMainIndex(java.lang.String tableName, java.lang.Object ValueToMatch) Returns a DB_Register whose main index matches a predetermined keyword in a specific table
java.util.Vector	getUniqueValues(java.lang.String tableName, java.lang.String FieldName) Returns a vector of Objects with unique values for a given property
static void	main(java.lang.String[] args) An extensive test for the Database engine

Methods inherited from class java.lang.Object

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

Field Detail

SMALLER_THAN

public static final int SMALLER_THAN

The value used to indicate a SMALLER_THAN type of comparison

See Also:

Constant Field Values

EQUAL_TO

public static final int EQUAL_TO

The value used to indicate a EQUAL_TO type of comparison

See Also:

Constant Field Values

GREATER_THAN

public static final int GREATER_THAN

The value used to indicate a GREATER_THAN type of comparison

See Also:

Constant Field Values

Constructor Detail

DataBaseEngine

public DataBaseEngine()

Creates a new instance of DataBaseEngine

Method Detail

addTable

public void addTable(java.lang.String tableName,
                     java.lang.String[] Fields,
                     java.lang.String[] Type)

Adds a DB_Table into the database engine

Parameters:

tableName - The name associated to this table

Fields - The properties of the registers in the table

Type - The type of register see DB_Table for details

addData

public void addData(java.lang.String tableName,
                    java.lang.String RegisterIndex,
                    java.lang.Object[] Values)

Adds an entry to one of the tables

Parameters:

tableName - The name associated to this table

RegisterIndex - A unique identifier for the register

Values - The Values to be assigned. Note: Values need to be in the same order than the Fields variable when the table was created

addData

public void addData(java.lang.String tableName,
                    java.lang.String RegisterIndex,
                    DB_Register Field)

Adds an entry to one of the tables

Parameters:

tableName - The name associated to this table

Field - The DB_Register to add

RegisterIndex - A unique identifier for the register

getRegisterByMainIndex

public DB_Register getRegisterByMainIndex(java.lang.String tableName,
                                          java.lang.Object ValueToMatch)

Returns a DB_Register whose main index matches a predetermined keyword in a specific table

Parameters:

tableName - The name associated to this table

ValueToMatch - The keyword to be matched

Returns:

The DB_Register found or null value

findRegister

public DB_Register[] findRegister(java.lang.String tableName,
                                  java.lang.String[] FieldName,
                                  java.lang.Object[] ValueToMatch)

Finds registers in a table that match a set of values criteria in several of its properties (e.g. in a gazetteer find all the "cities" that are in "colorado")

Parameters:

tableName - The name associated to this table

FieldName - The properties to match

ValueToMatch - The values to match

Returns:

The gruop of registers that match the imposed criteria

compareFieldsTo

public DB_Register[] compareFieldsTo(java.lang.String tableName,
                                     java.lang.String[] FieldName,
                                     java.lang.Object[] ValueToCompare,
                                     int[] ConditionToCheckFor)

A more general search for registers in a table. It compares registers with a a set of criteria in several of its properties. The criteria are:

0: equal to

-1: smaller than

1: greater than

Parameters:

tableName - The name associated to this table

FieldName - The properties to match

ValueToCompare - The values used as reference

ConditionToCheckFor - The conditions to apply to the reference value

Returns:

The gruop of registers that match the imposed criteria

getUniqueValues

public java.util.Vector getUniqueValues(java.lang.String tableName,
                                        java.lang.String FieldName)

Returns a vector of Objects with unique values for a given property

Parameters:

tableName - The name associated to this table

FieldName - The property to query

Returns:

The vector of unique values. For "Numeric" type properties a int[] is returned where int[0] is the minimum value and int[1] is the maximum value

getMaxValue

public java.lang.Double getMaxValue(java.lang.String tableName,
                                    java.lang.String FieldName)

Returns the maximum value for a given "Numeric" Property in a given table

Parameters:

tableName - The name associated to this table

FieldName - The property to query

Returns:

The maximum value

getMinValue

public java.lang.Double getMinValue(java.lang.String tableName,
                                    java.lang.String FieldName)

Returns the minimum value for a given "Numeric" Property in a given table

Parameters:

tableName - The name associated to this table

FieldName - The property to query

Returns:

The minimum value

main

public static void main(java.lang.String[] args)

An extensive test for the Database engine

Parameters:

args - the command line arguments