javatools.db
Class DbConstraint

java.lang.Object
  |
  +--javatools.db.DbConstraint

Direct Known Subclasses:

DbDynamicConstraint, FKAuthor, FKAuthorTelephoneNo, FKContainer, FKContains, FKData, FKDataSet, FKEditor, FKEditorTelephoneNo, FKFatherOf, FKFileType, FKGenre, FKIncludes, FKInstalledProgram, FKMarks, FKNeedsExecutionOf, FKPublished, FKRealized, FKSession, FKVolume

public abstract class DbConstraint

extends java.lang.Object

This abstract class represents a generic set of constraints for a table. It contains a lot of code already written for generic purposes, i.e. it can be derived with few code. If you want to add additional checks, you can easily add your own code, rewriting check and update methods.

Field Summary

protected boolean	automaticChecking true: check is done at all times; false: check is performed only with an explicit call to check.
protected boolean	canDoUpdate true: update can be done.
static int	CASCADE It means that, in case of an UPDATE/DELETE operation, the constraint MUST cascade the operation, that is updating/deleting in cascade all involved rows.
protected boolean	cloned true: the object is cloned.
protected boolean	constraintEmulation true: emulation made as needed; false: emulation is not made.
protected DbConstraint[]	constraints Contains an array of constraint to perform cascade-check and cascade-updates.
protected int	currentOperation Represents the current operation.
protected java.lang.Object[][]	defaultValues Contains default values for each referenced field of each father table.
static int	DELETE_OPERATION It represents a DELETE operation.
protected java.lang.Integer[]	deleteCascadeChildren Currently unused.
protected java.lang.Integer[]	deleteOperations It contains the delete operations for each father table.
static int	DO_NOTHING It means that, in case of an UPDATE/DELETE operation, the table MUST NOT do anything to repair itself.
protected DbColumn[][]	fatherColsChildren For each son, it contains the referenced column of THIS table.
protected DbTable	fatherRecords Contains the father records used to find eventually involved rows.
protected DbAbstractTable[]	fatherTables It contains all father tables of the one referenced by this constraint.
protected DbColumn[][]	fatherTablesColumns It contains the father keys for each father table.
protected java.util.List	fromList A list of values/expression to put data into (used in INSERT/UPDATE operations).
static int	INSERT_OPERATION It represents an INSERT operation.
protected java.util.List	intoList A list of columns to put data into (used in INSERT/UPDATE operations).
protected DbColumn[][]	refColsChildren For each son it contains the referenced columns of son tables.
protected DbColumn[][]	refColumns It contains for each father table, the referenced column in contained table.
protected java.lang.Integer[][]	refs It's an array built at runtime to represent, for each father, the referenced fields if they are specified in intoList for INSERT or UPDATE operations.
protected java.util.TreeSet[]	searchSets Contains the search sets used to perform checks for each son table.
protected DbSelector	selector A selector used in INSERT operations.
static int	SET_DEFAULT It means that, in case of an UPDATE/DELETE operation, the constraint MUST set an array of fields in involved rows to DEFAULT values, to repair referenced table.
static int	SET_NULL It means that, in case of an UPDATE/DELETE operation, the constraint MUST set an array of fields in involved rows to NULL values, to repair referenced table.
protected java.lang.Integer[]	sonIndexes For each son, it contains the position in the fatherTables of the son table itself.
protected DbExpr[]	sonsWhere Contains the "where" clauses for each son.
protected DbAbstractTable[]	sonTables It contains all son tables of the one referenced by this constraint.
protected DbAbstractTable	table The referenced table to check.
protected static int	UPDATE_CASCADE It means that an UPDATE-CASCADE operation is outgoing.
static int	UPDATE_OPERATION It represents a normal UPDATE operation.
protected java.lang.Integer[]	updateCascadeChildren Currently unused.
protected java.util.List[]	updateFromLists Contains an array of fromList-like lists, to perform update operations in son tables.
protected java.util.List[]	updateIntoLists Contains an array of intoList-like lists, to perform update operations in son tables.
protected java.lang.Integer[]	updateOperations It contains the update operations for each father table.
protected DbExpr	where A DbExpr clause used int DELETE/UPDATE operations.

Constructor Summary

DbConstraint()
Creates new DbConstraint

DbConstraint(DbAbstractTable tbl)
Creates a new DbConstraint for a specified table.

Method Summary

void	build() After all settings, it finally builds all static references.
abstract void	check(int operation) After setting all dynamic (i.e. operations, lists etc.) information, it checks explicitly if all operations can be done.
protected void	checkChildren() Checks recursively each son.
protected void	checkFathers() Performs checking for father tables.
protected void	checkThis(int operation) Performs base checks.
void	clear() Clears everything.
protected java.lang.Object	clone() Clones this object.
boolean	getAutomaticChecking() Returns the current automatic checking setting.
boolean	getConstraintEmulation() Returns if constraint emulation is enabled.
java.lang.Object[]	getDefaultValues(int index) Returns an array containing the default values for fields of a father table whose index is specified.
int	getDeleteOperation(int index) Returns what kind of operation will be done in case of a deletion of the father table specified by index.
DbColumn[]	getFatherColumns(int index) Returns the referenced father columns of a father table whose index is specified.
DbAbstractTable	getFatherTable(int index) Returns a father table whose index is specified.
int	getFatherTablesCount() Returns the number of referenced father tables.
DbColumn[]	getRefColumns(int index) Returns the referencing columns of THIS table for a father table whose index is specified.
int	getSonFatherIndex(int index) Returns in which position a son table references THIS table in its constraint.
DbAbstractTable	getSonTable(int index) Returns a son table whose index is specified.
int	getSonTablesCount() Returns the number of son tables.
DbAbstractTable	getTable() Returns the referenced table.
int	getUpdateOperation(int index) Returns what kind of operation will be done in case of an update of the father table specified by index.
protected void	initLists() Builds all dynamic lists (where clauses, constraints etc.).
protected void	initStaticLists() Inits static lists, like indexes of son tables, default values of father tables etc.
void	setAutomaticChecking(boolean value) Sets a flag to represent automatic checking at all times.
void	setConstraintEmulation(boolean value) Sets the constraint emulation.
void	setSelector(DbSelector pSelector) Sets the selector for an INSERT operation.
void	setValueLists(java.util.List pIntoList, java.util.List pFromList) Sets the lists to perform INSERT/UPDATE operations.
void	setWhere(DbExpr pWhere) Sets the "where" clause for an DELETE/UPDATE operation.
abstract int	update(int operation) Actually updates the table and all of its son tables.
protected int	updateThis(int operation) Performs base update.

Methods inherited from class java.lang.Object

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

Field Detail

INSERT_OPERATION

public static final int INSERT_OPERATION

It represents an INSERT operation.

See Also:

Constant Field Values

DELETE_OPERATION

public static final int DELETE_OPERATION

It represents a DELETE operation.

See Also:

Constant Field Values

UPDATE_OPERATION

public static final int UPDATE_OPERATION

It represents a normal UPDATE operation.

See Also:

Constant Field Values

UPDATE_CASCADE

protected static final int UPDATE_CASCADE

It means that an UPDATE-CASCADE operation is outgoing. It is protected because it is useful only for internal checks-updates.

See Also:

Constant Field Values

DO_NOTHING

public static final int DO_NOTHING

It means that, in case of an UPDATE/DELETE operation, the table MUST NOT do anything to repair itself.

See Also:

Constant Field Values

SET_NULL

public static final int SET_NULL

It means that, in case of an UPDATE/DELETE operation, the constraint MUST set an array of fields in involved rows to NULL values, to repair referenced table.

See Also:

Constant Field Values

SET_DEFAULT

public static final int SET_DEFAULT

It means that, in case of an UPDATE/DELETE operation, the constraint MUST set an array of fields in involved rows to DEFAULT values, to repair referenced table.

See Also:

Constant Field Values

CASCADE

public static final int CASCADE

It means that, in case of an UPDATE/DELETE operation, the constraint MUST cascade the operation, that is updating/deleting in cascade all involved rows.

See Also:

Constant Field Values

table

protected DbAbstractTable table

The referenced table to check.

where

protected DbExpr where

A DbExpr clause used int DELETE/UPDATE operations.

selector

protected DbSelector selector

A selector used in INSERT operations.

intoList

protected java.util.List intoList

A list of columns to put data into (used in INSERT/UPDATE operations).

fromList

protected java.util.List fromList

A list of values/expression to put data into (used in INSERT/UPDATE operations).

automaticChecking

protected boolean automaticChecking

true: check is done at all times; false: check is performed only with an explicit call to check.

constraintEmulation

protected boolean constraintEmulation

true: emulation made as needed; false: emulation is not made.

currentOperation

protected int currentOperation

Represents the current operation. (INSERT, DELETE, UPDATE, UPDATE-CASCADE).

canDoUpdate

protected boolean canDoUpdate

true: update can be done. false: update CANNOT be done. It is put to false whenever the DBMS can perform referencial integrity check by itself; e.g. MySQL cannot, so it must be done in a "software" way.

fatherTables

protected DbAbstractTable[] fatherTables

It contains all father tables of the one referenced by this constraint.

sonTables

protected DbAbstractTable[] sonTables

It contains all son tables of the one referenced by this constraint.

updateOperations

protected java.lang.Integer[] updateOperations

It contains the update operations for each father table.

deleteOperations

protected java.lang.Integer[] deleteOperations

It contains the delete operations for each father table.

fatherTablesColumns

protected DbColumn[][] fatherTablesColumns

It contains the father keys for each father table.

refColumns

protected DbColumn[][] refColumns

It contains for each father table, the referenced column in contained table. That is each element in fatherTablesColumns, columns of father tables, must be equal to each element in refColumns, columns of THIS table.

fatherColsChildren

protected DbColumn[][] fatherColsChildren

For each son, it contains the referenced column of THIS table. It is built automatically, to ease checking.

refColsChildren

protected DbColumn[][] refColsChildren

For each son it contains the referenced columns of son tables. It is built automatically, to ease checking.

sonIndexes

protected java.lang.Integer[] sonIndexes

For each son, it contains the position in the fatherTables of the son table itself.

refs

protected java.lang.Integer[][] refs

It's an array built at runtime to represent, for each father, the referenced fields if they are specified in intoList for INSERT or UPDATE operations.

searchSets

protected java.util.TreeSet[] searchSets

Contains the search sets used to perform checks for each son table.

sonsWhere

protected DbExpr[] sonsWhere

Contains the "where" clauses for each son.

fatherRecords

protected DbTable fatherRecords

Contains the father records used to find eventually involved rows.

deleteCascadeChildren

protected java.lang.Integer[] deleteCascadeChildren

Currently unused.

updateCascadeChildren

protected java.lang.Integer[] updateCascadeChildren

Currently unused.

constraints

protected DbConstraint[] constraints

Contains an array of constraint to perform cascade-check and cascade-updates.

defaultValues

protected java.lang.Object[][] defaultValues

Contains default values for each referenced field of each father table.

updateIntoLists

protected java.util.List[] updateIntoLists

Contains an array of intoList-like lists, to perform update operations in son tables.

updateFromLists

protected java.util.List[] updateFromLists

Contains an array of fromList-like lists, to perform update operations in son tables.

cloned

protected boolean cloned

true: the object is cloned. false: the object is NOT cloned.

Constructor Detail

DbConstraint

public DbConstraint()

Creates new DbConstraint

DbConstraint

public DbConstraint(DbAbstractTable tbl)

Creates a new DbConstraint for a specified table.

Parameters:

tbl - The table to be checked.

Method Detail

getTable

public DbAbstractTable getTable()

Returns the referenced table.

Returns:

The referenced table.

setWhere

public void setWhere(DbExpr pWhere)

Sets the "where" clause for an DELETE/UPDATE operation.

Parameters:

pWhere - The requested clause.

setSelector

public void setSelector(DbSelector pSelector)

Sets the selector for an INSERT operation.

Parameters:

pSelector - The requested selector.

setValueLists

public void setValueLists(java.util.List pIntoList,
                          java.util.List pFromList)

Sets the lists to perform INSERT/UPDATE operations.

Parameters:

pIntoList - It will be put into intoList.

pFromList - It will be put into fromList.

setAutomaticChecking

public void setAutomaticChecking(boolean value)

Sets a flag to represent automatic checking at all times.

Parameters:

value - true: check is done at all times; false: check is performed only with an explicit call to check.

getAutomaticChecking

public boolean getAutomaticChecking()

Returns the current automatic checking setting.

Returns:

true: check is done at all times; false: check is performed only with an explicit call to check.

setConstraintEmulation

public void setConstraintEmulation(boolean value)

Sets the constraint emulation.

Parameters:

value - true: constraint emulation is done as needed; false: constraint emulation is NEVER done.

getConstraintEmulation

public boolean getConstraintEmulation()

Returns if constraint emulation is enabled.

Returns:

true: constraint emulation is done as needed; false: constraint emulation is NEVER done.

getFatherTablesCount

public int getFatherTablesCount()

Returns the number of referenced father tables.

Returns:

The count of referenced father tables.

getSonTablesCount

public int getSonTablesCount()

Returns the number of son tables.

Returns:

The son tables count.

getFatherTable

public DbAbstractTable getFatherTable(int index)
                               throws DbException

Returns a father table whose index is specified.

Parameters:

index - The index of a father table.

Returns:

The requested father table.

Throws:

DbException - If something goes wrong.

getSonTable

public DbAbstractTable getSonTable(int index)
                            throws DbException

Returns a son table whose index is specified.

Parameters:

index - The index of a son table.

Returns:

The requested son table.

Throws:

DbException - If something goes wrong.

getSonFatherIndex

public int getSonFatherIndex(int index)
                      throws DbException

Returns in which position a son table references THIS table in its constraint.

Parameters:

index - The son table index.

Returns:

The needed index.

Throws:

DbException - If something goes wrong.

getUpdateOperation

public int getUpdateOperation(int index)
                       throws DbException

Returns what kind of operation will be done in case of an update of the father table specified by index.

Parameters:

index - The index of the father table.

Returns:

The requested operation.

Throws:

DbException - If something goes wrong.

getDeleteOperation

public int getDeleteOperation(int index)
                       throws DbException

Returns what kind of operation will be done in case of a deletion of the father table specified by index.

Parameters:

index - The index of the father table.

Returns:

The requested operation.

Throws:

DbException - If something goes wrong.

getFatherColumns

public DbColumn[] getFatherColumns(int index)
                            throws DbException

Returns the referenced father columns of a father table whose index is specified.

Parameters:

index - The index of the father table.

Returns:

An array containing the referenced father columns.

Throws:

DbException - If something goes wrong.

getRefColumns

public DbColumn[] getRefColumns(int index)
                         throws DbException

Returns the referencing columns of THIS table for a father table whose index is specified.

Parameters:

index - The index of the father column.

Returns:

The referencing columns.

Throws:

DbException - If something goes wrong.

getDefaultValues

public java.lang.Object[] getDefaultValues(int index)
                                    throws DbException

Returns an array containing the default values for fields of a father table whose index is specified.

Parameters:

index - The index of the father table.

Returns:

An array containing the default values for referencing columns related to requested father table.

Throws:

DbException - If something goes wrong.

clear

public void clear()

Clears everything.

build

public void build()
           throws DbException

After all settings, it finally builds all static references.

Throws:

DbException - If something goes wrong.

check

public abstract void check(int operation)
                    throws DbException

After setting all dynamic (i.e. operations, lists etc.) information, it checks explicitly if all operations can be done. I suggest to call checkThis method to perform base checking.

Parameters:

operation - The kind of operation (INSERT, UPDATE etc.) that should be done.

Throws:

DbException - If something goes wrong.

update

public abstract int update(int operation)
                    throws DbException

Actually updates the table and all of its son tables. I suggest to call updateThis method to perform base update.

Parameters:

operation - The kind of operation (INSERT, UPDATE etc.) that should be done.

Returns:

It should contain the final result of execute calls to inserters, deleters of updaters.

Throws:

DbException - If something goes wrong.

updateThis

protected int updateThis(int operation)
                  throws DbException

Performs base update. It also checks if automatic checking is set.

Parameters:

operation - The operation to be done.

Returns:

The real result from an inserter, updater, deleter.

Throws:

DbException - If something goes wrong.

checkThis

protected void checkThis(int operation)
                  throws DbException

Performs base checks.

Parameters:

operation - The operations that should be done.

Throws:

DbException - If something goes wrong.

checkFathers

protected void checkFathers()
                     throws DbException

Performs checking for father tables. Used in INSERT and UPDATE operations. N.B. Not used in UPDATE-CASCADE operation.

Throws:

DbException - If checking fails.

checkChildren

protected void checkChildren()
                      throws DbException

Checks recursively each son.

Throws:

DbException - If checking fails.

clone

protected java.lang.Object clone()
                          throws java.lang.CloneNotSupportedException

Clones this object. It is used to build a temporary DbConstraint in self-referencing tables.

Overrides:

clone in class java.lang.Object

Returns:

The cloned object.

Throws:

java.lang.CloneNotSupportedException - Never thrown... usually...

initStaticLists

protected void initStaticLists()
                        throws DbException

Inits static lists, like indexes of son tables, default values of father tables etc.

Throws:

DbException - If something goes wrong.

initLists

protected void initLists()
                  throws DbException

Builds all dynamic lists (where clauses, constraints etc.).

Throws:

DbException - If something goes wrong.