com.ibm.commerce.base.helpers

Class OptCounterInfo

java.lang.Object

com.ibm.commerce.base.helpers.OptCounterInfo

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public final class OptCounterInfo
extends java.lang.Object
implements java.lang.Cloneable, java.io.Serializable

This class contains information about the value of the OPTCOUNTER column for a row in a database table.

The OptCounterInfo class defines four properties:

Known

Is set to "true" if the CurrentValue matches the value in the database, and so it can be included in a WHERE clause. A value that has been incremented or randomized does not need to be included in the WHERE clause. It is assumed that an increment or randomize operation is only performed when a database write lock has been obtained.

Null

Is set to "true" if the CurrentValue to be included in the WHERE clause is null.

CurrentValue

Represents the value to be included in the WHERE clause if the Null property is "false".

EJBLoaded

Is set to "true" if the value gets loaded using ejbLoad().

The new CurrentValue represents the value to be set when inserting or updating a row.

Use this class in the following cases:

• When an EJB bean is loaded.

  Get the saved value from the TransactionCache, replace it with the loaded value, and set EJBLoaded to "true". The EJBLoaded value is set to "true" so that a subsequent JDBC update knows it must flush the EJB cache before it performs an UPDATE operation. Do this by ensuring your EJB calls super.ejbLoad().

• When an EJB bean is saved.

  Get the saved value from the TransactionCache and replace it with the loaded value. Increment the loaded value and set the EJB attribute value to the incremented value. The incremented value is saved so that a subsequent JDBC SELECT operation does not need to read it from the database, and so that a subsequent JDBC UPDATE operation has the correct value for the WHERE clause. Do this by ensuring your EJB bean calls super.ejbStore().

• When a SELECT statement is used to obtain the OPTCOUNTER value.

  Save the value in the TransactionCache. This is optional, depending on the application logic, but if it is not done, an intervening change may not be detected.

  Refer to OPTCOUNTER_COLUMN_NAME, getSavedOptCounterInfo(Object), and setCurrentValue(boolean,ResultSet,int).

• When a SELECT ... FOR UPDATE statement is used to obtain the OPTCOUNTER value.

  When the OPTCOUNTER value is known, obtained, for example by a previously executed SELECT statement, include the OPTCOUNTER value in the WHERE clause if it is known and has never been incremented or randomized, and throw an ECJDBCOptimisticUpdateFailureException if the row is not found.

  Refer to getSelectForUpdateSQL(String), BaseJDBCHelper.getSavedOptCounterInfoForOptimisticSelect(Object), getWhereClauseFragment(), setParameter(PreparedStatement,int), ECJDBCOptimisticUpdateFailureException, and BaseJDBCHelper.executeOptimisticSelect(PreparedStatement,Object,OptCounterInfo).

• When a DELETE operation is followed by an INSERT operation in the same transaction.

  A DELETE operation followed by an INSERT operation should appear to another transaction as equivalent to an UPDATE operation.

  Before a DELETE statement is executed, determine the current OPTCOUNTER value and save it in the TransactionCache. This is optional depending on the application logic. If there is already a value in the TransactionCache, you can use that value rather than reading it from the database. If no subsequent INSERT operation occurs in the same transaction, it is not necessary to determine and save it. When a DELETE statement is executed, get the saved value from the TransactionCache and include it in the WHERE clause if it is known and has never been incremented or randomized. If the DELETE statement includes the OPTCOUNTER value in the WHERE clause and executes successfully but does not delete any rows, throw an ECJDBCOptimisticUpdateFailureException exception.

  Refer to getSelectOptCounterSQL(String,String), BaseJDBCHelper.getSavedOptCounterInfoForDelete(Object), getWhereClauseFragment(), setParameter(PreparedStatement,int), ECJDBCOptimisticUpdateFailureException, and BaseJDBCHelper.executeOptimisticDelete(PreparedStatement,Object,OptCounterInfo).

• When an INSERT statement is executed.

  Get the saved value from the TransactionCache, increment it, and use it in the INSERT operation. If there is no saved value, randomly select a value, use it in the INSERT operation, and save it in the TransactionCache. By randomly selecting a value, the chance that another transaction does not detect the change introduced by a DELETE operation followed by an INSERT operation is reduced. This is only necessary when the application logic performs a DELETE operation followed by an INSERT operation in the same transaction. Refer to getSavedOptCounterInfoForInsert(Object) and setParameter(PreparedStatement,int).

• When an UPDATE statement is executed.

  Include the update fragment to increment the counter, get the saved value from the TransactionCache and include it in the WHERE clause if it is known and has never been incremented or randomized. If the update statement includes the OPTCOUNTER value in the WHERE clause but does not find the specified row, throw an ECJDBCOptimisticUpdateFailureException exception. Otherwise, increment the saved value. Refer to getIncrementOptCounterFragment(), BaseJDBCHelper.getSavedOptCounterInfoForUpdate(Object), getWhereClauseFragment(), setParameter(PreparedStatement,int), ECJDBCOptimisticUpdateFailureException, and BaseJDBCHelper.executeOptimisticUpdate(PreparedStatement,Object,OptCounterInfo).

Note: Some operations are not supported. For example, JDBC cannot be used to update a row after it has been loaded into an EJB bean and before the bean has been stored. It is better to avoid mixing EJB beans and JDBC for the same database information. If necessary, use the BaseJDBCHelper.getSavedOptCounterInfoForUpdate(Object) method to cause dirty EJB objects to be flushed to the database before executing a JDBC update operation.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	OPTCOUNTER_COLUMN_NAME The name of the OPTCOUNTER column.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	clone() Returns a copy of this OptCounterInfo object.
static OptCounterInfo	getAndForgetForNextInsert() Gets and increments the object most recently set by the setForNextInsert method, or creates and randomizes a new one created from the default constructor.
short	getCurrentValue() Get the current OPTCOUNTER value.
static java.lang.String	getDecrementOptCounterFragment() Returns an SQL fragment that can be used to decrement the current OPTCOUNTER value.
static java.lang.String	getDecrementSQL(java.lang.String astrUpdateFragment, java.lang.String astrWhereClauseFragment) Returns a simple UPDATE statement with appropriate phrase to decrement the OPTCOUNTER column.
static java.lang.String	getIncrementOptCounterFragment() Returns an SQL fragment that can be used to increment the current OPTCOUNTER value.
static java.lang.String	getIncrementSQL(java.lang.String astrUpdateFragment, java.lang.String astrWhereClauseFragment) Returns a simple UPDATE statement with appropriate phrase to increment the OPTCOUNTER column.
static short	getNextValue(short aCurrentOptCounterValue) Gets the next value of the OPTCOUNTER column (incremented with wrap to 1).
java.lang.String	getOptimisticDecrementSQL(java.lang.String astrTableName, java.lang.String astrWhereClause) Returns an SQL statement that can be used to decrement the OPTCOUNTER column of a specific row.
java.lang.String	getOptimisticIncrementSQL(java.lang.String astrTableName, java.lang.String astrWhereClause) Returns an SQL statement that can be used to increment the OPTCOUNTER column of a specific row.
java.lang.String	getOptimisticSelectForUpdateSQL(java.lang.String astrSelectFragment) Returns a simple SELECT statement with the appropriate phrases to include a previously read opt counter (if any) in the WHERE clause, and to obtain a FOR UPDATE lock.
java.lang.String	getOptimisticSelectForUpdateSQL(java.lang.String astrSelectFragment, java.lang.String astrWhereClauseFragment) Returns a simple SELECT statement with the appropriate phrases to obtain the opt counter value from the database, to include a previously read opt counter (if any) in the WHERE clause, and to obtain a FOR UPDATE lock.
java.lang.String	getOptimisticSelectSQL(java.lang.String astrSelectFragment, java.lang.String astrWhereClauseFragment) Returns a simple SELECT statement with the appropriate phrases to obtain the opt counter and include it in the WHERE clause.
static OptCounterInfo	getSavedOptCounterInfo(java.lang.Object aKey) Gets the OPTCOUNTER information for a row of a table from the TransactionCache.
static OptCounterInfo	getSavedOptCounterInfoForInsert(java.lang.Object aKey) Gets OPTCOUNTER information to be used in an INSERT operation.
static java.lang.String	getSelectForUpdateFragment() Returns an SQL fragment that can be used to obtain a FOR UPDATE lock.
static java.lang.String	getSelectForUpdateSQL(java.lang.String astrSelectFragment) Returns a simple SELECT statement with an appropriate phrase to obtain a FOR UPDATE lock.
static java.lang.String	getSelectOptCounterSQL(java.lang.String astrTableName, java.lang.String astrWhereClause) This method gets an SQL statement that can be used to obtain the current values of the OPTCOUNTER column.
static java.lang.String	getSelectOptCounterSQL(java.lang.String astrTableName, java.lang.String astrColumnName, java.lang.String astrWhereClause) This method gets an SQL statement that can be used to obtain the current values of a specified column and of the OPTCOUNTER column.
java.lang.String	getUpdateSQL(java.lang.String astrUpdateFragment, java.lang.String astrWhereClauseFragment) Returns a simple UPDATE SQL statement with appropriate optimistic locking phrases.
java.lang.String	getUpdateSQL(java.lang.String astrUpdateFragment, java.lang.String astrWhereClausePrefixFragment, java.lang.String astrWhereClausePostfixFragment) Returns a simple UPDATE SQL statement with appropriate optimistic locking phrases.
java.lang.String	getWhereClauseFragment() Returns either "" (if the value is not known or has been incremented or randomized), or " AND OPTCOUNTER IS NULL" (if the value is null), or " AND OPTCOUNTER=?" (if the value is not null).
OptCounterInfo	increment() Increment the current value (with wrap to 1).
boolean	isEJBLoaded() Gets whether the current OPTCOUNTER value is loaded using ejbLoad().
boolean	isKnown() Gets whether the current OPTCOUNTER value is known.
boolean	isNull() Gets whether the current OPTCOUNTER value is null.
OptCounterInfo	randomize() Sets the current value to a randomly assigned value.
OptCounterInfo	setCurrentValue(boolean abRowExists, java.sql.ResultSet aResultSet) Sets the current OPTCOUNTER information from a ResultSet.
OptCounterInfo	setCurrentValue(boolean abRowExists, java.sql.ResultSet aResultSet, int aIndex) Sets the current OPTCOUNTER information from a ResultSet.
OptCounterInfo	setCurrentValue(java.lang.Number anCurrentOptCounterValue) Sets the current known OPTCOUNTER value, which may be null.
OptCounterInfo	setCurrentValue(short aCurrentOptCounterValue) Sets the current known, not null, OPTCOUNTER value.
OptCounterInfo	setCurrentValue(java.lang.Short anCurrentOptCounterValue) Sets the current known OPTCOUNTER value, which may be null.
OptCounterInfo	setEJBLoaded() Sets the property that indicates that the current OPTCOUNTER value was loaded using ejbLoad().
OptCounterInfo	setEJBLoaded(boolean abEJBLoaded) Sets whether the current OPTCOUNTER value was loaded using ejbLoad().
static OptCounterInfo	setForNextInsert(OptCounterInfo aOptCounterInfo) Sets an OptCounterInfo object that will be recalled by the next execution of the getAndForgetForNextInsert method.
OptCounterInfo	setKnown(boolean abKnown) Sets whether the current OPTCOUNTER value is known.
OptCounterInfo	setNull(boolean abNull) Sets whether the current known OPTCOUNTER value is null.
OptCounterInfo	setParameter(java.sql.PreparedStatement aPreparedStatement, int aIndex) Sets the OPTCOUNTER value into the specified PreparedStatement at the specified position, if it is known and not null, has not been incremented, and has not been randomized.
java.lang.String	toString() Returns a String representation of this object suitable for printing in trace information.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

OPTCOUNTER_COLUMN_NAME

public static final java.lang.String OPTCOUNTER_COLUMN_NAME

The name of the OPTCOUNTER column.

See Also:

Constant Field Values

Method Detail

getSelectOptCounterSQL

public static java.lang.String getSelectOptCounterSQL(java.lang.String astrTableName,
                                                      java.lang.String astrWhereClause)

This method gets an SQL statement that can be used to obtain the current values of the OPTCOUNTER column. It retrieves them from the specified table for the rows indicated by the specified WHERE clause. The WHERE clause should not start with "WHERE".

Parameters:

astrTableName - The table name

astrWhereClause - The WHERE clause

Returns:

the SQL statement.

getSelectOptCounterSQL

public static java.lang.String getSelectOptCounterSQL(java.lang.String astrTableName,
                                                      java.lang.String astrColumnName,
                                                      java.lang.String astrWhereClause)

This method gets an SQL statement that can be used to obtain the current values of a specified column and of the OPTCOUNTER column. It retrieves them from the specified table for the rows indicated by the specified WHERE clause. The WHERE clause should not start with "WHERE". The SQL statement returned is: "SELECT " + OPTCOUNTER_COLUMN_NAME + "," + astrColumnName + ","+ OPTCOUNTER_COLUMN_NAME + " FROM " + astrTableName + " WHERE " + astrWhereClause

Parameters:

astrTableName - The table name.

astrColumnName - The column name.

astrWhereClause - The where clause.

Returns:

The SQL statement.

getSelectForUpdateFragment

public static java.lang.String getSelectForUpdateFragment()

Returns an SQL fragment that can be used to obtain a FOR UPDATE lock. It can be used in an SQL SELECT statement such as: "SELECT acolumn FROM tablename WHERE conditions" + OptCounterInfo.getForUpdateFragment()

Do not call this method during static initialization.

Returns:

the SQL fragment.

getSelectForUpdateSQL

public static java.lang.String getSelectForUpdateSQL(java.lang.String astrSelectFragment)

Returns a simple SELECT statement with an appropriate phrase to obtain a FOR UPDATE lock.

The string returned is:

• astrSelectFragment + getSelectForUpdateFragment()

Do not call this method during static initialization.

Parameters:

astrSelectFragment - the update SQL fragment.

Returns:

the SQL statement.

getIncrementOptCounterFragment

public static java.lang.String getIncrementOptCounterFragment()

Returns an SQL fragment that can be used to increment the current OPTCOUNTER value. It can be used in an SQL UPDATE statement such as:

• "UPDATE tablename SET " + OptCounterInfo.getIncrementOptCounterFragment() + " WHERE column2Name=column2Value"

Do not call this method during static initialization.

Returns:

the SQL fragment.

getIncrementSQL

public static java.lang.String getIncrementSQL(java.lang.String astrUpdateFragment,
                                               java.lang.String astrWhereClauseFragment)

Returns a simple UPDATE statement with appropriate phrase to increment the OPTCOUNTER column.

The string returned is:

• astrUpdateFragment + getIncrementOptCounterFragment() + astrWhereClauseFragment

Do not call this method during static initialization.

Parameters:

astrUpdateFragment - the update SQL fragment.

astrWhereClauseFragment - the WHERE clause fragment.

Returns:

the SQL statement.

getDecrementOptCounterFragment

public static java.lang.String getDecrementOptCounterFragment()

Returns an SQL fragment that can be used to decrement the current OPTCOUNTER value. It can be used in an SQL "UPDATE" statement such as:

• "UPDATE tablename SET " + OptCounterInfo.getDecrementOptCounterFragment() +" WHERE column2Name=column2Value"

Do not call this method during static initialization.

Returns:

the SQL fragment.

getDecrementSQL

public static java.lang.String getDecrementSQL(java.lang.String astrUpdateFragment,
                                               java.lang.String astrWhereClauseFragment)

Returns a simple UPDATE statement with appropriate phrase to decrement the OPTCOUNTER column.

The string returned is:

• astrUpdateFragment + getDecrementOptCounterFragment() + astrWhereClauseFragment

Do not call this method during static initialization.

Parameters:

astrUpdateFragment - the update SQL fragment.

astrWhereClauseFragment - the WHERE clause fragment.

Returns:

the SQL statement.

getNextValue

public static short getNextValue(short aCurrentOptCounterValue)

Gets the next value of the OPTCOUNTER column (incremented with wrap to 1).

Parameters:

aCurrentOptCounterValue - the current value to be incremented.

Returns:

the new incremented value of the OPTCOUNTER column.

getSavedOptCounterInfo

public static OptCounterInfo getSavedOptCounterInfo(java.lang.Object aKey)

Gets the OPTCOUNTER information for a row of a table from the TransactionCache.

Parameters:

aKey - uniquely identifies the table and row of the OPTCOUNTER. For objects with EJB beans, use its primary key object. For example, for a UserBean, use new MemberKey(member_id) For JDBC helper classes when there is no corresponding EJB bean, use a unique row identifier. For example, new SerializableTuple("STOREREL", storeId, relatedStoreId, relationshipTypeName)

Returns:

the OPTCOUNTER information for the specified row, or a new OptCounterInfo constructed from the default constructor if there was none in the Transaction cache.

getSavedOptCounterInfoForInsert

public static OptCounterInfo getSavedOptCounterInfoForInsert(java.lang.Object aKey)

Gets OPTCOUNTER information to be used in an INSERT operation. The object returned can be the current saved OptCounterInfo object with its value incremented, if it is known. Or, it can be a new OptCounterInfo object created with the default constructor, that is randomly assigned a value. In either case, the value returned is saved and marked as known. Do not call this method if there is a possibility that the INSERT operation will not be performed.

Parameters:

aKey - uniquely identifies the table and row of the OPTCOUNTER. For objects with EJB beans, use its primary key object. For example, for a UserBean, use new MemberKey(member_id) For JDBC helper classes when there is no corresponding EJB, use a unique row identifier. For example, new SerializableTuple("STOREREL", storeId, relatedStoreId, relationshipTypeName)

Returns:

the OPTCOUNTER information for the specified row, to be used in a subsequent insert operation.

setForNextInsert

public static OptCounterInfo setForNextInsert(OptCounterInfo aOptCounterInfo)

Sets an OptCounterInfo object that will be recalled by the next execution of the getAndForgetForNextInsert method.

Parameters:

aOptCounterInfo - the object to be set. Can be null.

Returns:

the input parameter.

getAndForgetForNextInsert

public static OptCounterInfo getAndForgetForNextInsert()

Gets and increments the object most recently set by the setForNextInsert method, or creates and randomizes a new one created from the default constructor. Then forgets it until the setForNextInsert method is called again.

Returns:

the OPTCOUNTER information.

setCurrentValue

public OptCounterInfo setCurrentValue(short aCurrentOptCounterValue)

Sets the current known, not null, OPTCOUNTER value. Side effects: Null is set false, Known is set true.

Parameters:

aCurrentOptCounterValue - the value to be set.

Returns:

this.

setCurrentValue

public OptCounterInfo setCurrentValue(java.lang.Short anCurrentOptCounterValue)

Sets the current known OPTCOUNTER value, which may be null. Side effects: Known is set true.

Parameters:

anCurrentOptCounterValue - the value to be set.

Returns:

this.

setCurrentValue

public OptCounterInfo setCurrentValue(java.lang.Number anCurrentOptCounterValue)

Sets the current known OPTCOUNTER value, which may be null. Side effects: Known is set true.

Parameters:

anCurrentOptCounterValue - the value to be set.

Returns:

this.

setCurrentValue

public OptCounterInfo setCurrentValue(boolean abRowExists,
                                      java.sql.ResultSet aResultSet)
                               throws java.sql.SQLException

Sets the current OPTCOUNTER information from a ResultSet. Known is set to abRowExists.

Parameters:

abRowExists - true if aResultSet has been set to the correct row.

aResultSet - not used if abRowExists is false.

Returns:

this.

Throws:

java.sql.SQLException

setCurrentValue

public OptCounterInfo setCurrentValue(boolean abRowExists,
                                      java.sql.ResultSet aResultSet,
                                      int aIndex)
                               throws java.sql.SQLException

Sets the current OPTCOUNTER information from a ResultSet. Known is set to abRowExists.

Parameters:

abRowExists - true if aResultSet has been set to the correct row.

aResultSet - not used if abRowExists is false.

aIndex - the index of the OPTCOUNTER column in the result set. Not used if abRowExists is false.

Returns:

this.

Throws:

java.sql.SQLException

setNull

public OptCounterInfo setNull(boolean abNull)

Sets whether the current known OPTCOUNTER value is null. Side effect: Known is set true.

Parameters:

abNull - true if the value is null.

Returns:

this.

setKnown

public OptCounterInfo setKnown(boolean abKnown)

Sets whether the current OPTCOUNTER value is known.

Parameters:

abKnown - true if the value is known.

Returns:

this.

setEJBLoaded

public OptCounterInfo setEJBLoaded(boolean abEJBLoaded)

Sets whether the current OPTCOUNTER value was loaded using ejbLoad().

Parameters:

abEJBLoaded - true if the value was loaded using ejbLoad().

Returns:

this.

setEJBLoaded

public OptCounterInfo setEJBLoaded()

Sets the property that indicates that the current OPTCOUNTER value was loaded using ejbLoad().

Returns:

this.

getCurrentValue

public short getCurrentValue()

Get the current OPTCOUNTER value.

Returns:

the current OPTCOUNTER value.

increment

public OptCounterInfo increment()

Increment the current value (with wrap to 1).

Side effect: Null is set false.

Side effect: The WHERE clause fragment for an incremented OPTCOUNTER is always empty, since incrementing the value implies that the row has been updated. This means that a write lock has been obtained, hence no other transaction can modify the row until this transaction commits, and so the WHERE clause fragment that detects changes is not required.

Returns:

this.

randomize

public OptCounterInfo randomize()

Sets the current value to a randomly assigned value.

Side effect: Null is set false.

Side effect: The WHERE clause fragment for a randomized OPTCOUNTER is always empty, since randomizing the value implies that the row has been created. This means that a write lock has been obtained, hence no other transaction can modify the row until this transaction commits, and so the WHERE clause fragment that detects changes is not required.

Returns:

this.

isNull

public boolean isNull()

Gets whether the current OPTCOUNTER value is null.

Returns:

true if the current OPTCOUNTER value is null.

isKnown

public boolean isKnown()

Gets whether the current OPTCOUNTER value is known.

Returns:

true if the current OPTCOUNTER value is known.

isEJBLoaded

public boolean isEJBLoaded()

Gets whether the current OPTCOUNTER value is loaded using ejbLoad().

Returns:

true if the current OPTCOUNTER value is loaded using ejbLoad().

clone

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

Returns a copy of this OptCounterInfo object.

Overrides:

clone in class java.lang.Object

Returns:

a copy of this OptCounterInfo object.

Throws:

java.lang.CloneNotSupportedException

toString

public java.lang.String toString()

Returns a String representation of this object suitable for printing in trace information.

Overrides:

toString in class java.lang.Object

Returns:

a String representation of this object suitable for printing in trace information.

getWhereClauseFragment

public java.lang.String getWhereClauseFragment()

Returns either "" (if the value is not known or has been incremented or randomized), or " AND OPTCOUNTER IS NULL" (if the value is null), or " AND OPTCOUNTER=?" (if the value is not null).

Returns:

the WHERE clause fragment.

getUpdateSQL

public java.lang.String getUpdateSQL(java.lang.String astrUpdateFragment,
                                     java.lang.String astrWhereClauseFragment)

Returns a simple UPDATE SQL statement with appropriate optimistic locking phrases.

The string returned is:

• astrUpdateFragment + "," + getIncrementOptCounterFragment() + " " + astrWhereClauseFragment + getWhereClauseFragment()

Do not call this method during static initialization.

Parameters:

astrUpdateFragment - the UPDATE SQL fragment.

astrWhereClauseFragment - the WHERE clause fragment.

Returns:

the SQL statement.

getUpdateSQL

public java.lang.String getUpdateSQL(java.lang.String astrUpdateFragment,
                                     java.lang.String astrWhereClausePrefixFragment,
                                     java.lang.String astrWhereClausePostfixFragment)

Returns a simple UPDATE SQL statement with appropriate optimistic locking phrases.

The string returned is:

• astrUpdateFragment + "," + getIncrementOptCounterFragment() + " " + astrWhereClausePrefixFragment + getWhereClauseFragment() + astrWhereClausePostfixFragment

Do not call this method during static initialization.

Parameters:

astrUpdateFragment - the UPDATE SQL fragment.

astrWhereClausePrefixFragment - the WHERE clause prefix fragment.

astrWhereClausePostfixFragment - the WHERE clause postfix fragment.

Returns:

the SQL statement.

getOptimisticSelectSQL

public java.lang.String getOptimisticSelectSQL(java.lang.String astrSelectFragment,
                                               java.lang.String astrWhereClauseFragment)

Returns a simple SELECT statement with the appropriate phrases to obtain the opt counter and include it in the WHERE clause.

The string returned is:

• astrSelectFragment + "," + OPTCOUNTER_COLUMN_NAME + " " + astrWhereClauseFragment + getWhereClauseFragment()

Do not call this method during static initialization.

Parameters:

astrSelectFragment - the select SQL fragment.

astrWhereClauseFragment - the WHERE clause fragment.

Returns:

the SQL statement.

getOptimisticIncrementSQL

public java.lang.String getOptimisticIncrementSQL(java.lang.String astrTableName,
                                                  java.lang.String astrWhereClause)

Returns an SQL statement that can be used to increment the OPTCOUNTER column of a specific row.

Parameters:

astrTableName - the table name.

astrWhereClause - a WHERE clause (should NOT start with "WHERE") that uniquely identifies the row.

Returns:

the SQL statement.

getOptimisticDecrementSQL

public java.lang.String getOptimisticDecrementSQL(java.lang.String astrTableName,
                                                  java.lang.String astrWhereClause)

Returns an SQL statement that can be used to decrement the OPTCOUNTER column of a specific row.

Parameters:

astrTableName - the table name.

astrWhereClause - a WHERE clause (should NOT start with "WHERE") that uniquely identifies the row.

Returns:

the SQL statement.

getOptimisticSelectForUpdateSQL

public java.lang.String getOptimisticSelectForUpdateSQL(java.lang.String astrSelectFragment,
                                                        java.lang.String astrWhereClauseFragment)

Returns a simple SELECT statement with the appropriate phrases to obtain the opt counter value from the database, to include a previously read opt counter (if any) in the WHERE clause, and to obtain a FOR UPDATE lock.

The string returned is:

• astrSelectFragment + "," + OPTCOUNTER_COLUMN_NAME + " " + astrWhereClauseFragment + getWhereClauseFragment() + getSelectForUpdateFragment()

Do not call this method during static initialization.

Parameters:

astrSelectFragment - the select SQL fragment.

astrWhereClauseFragment - the WHERE clause fragment.

Returns:

the SQL statement.

getOptimisticSelectForUpdateSQL

public java.lang.String getOptimisticSelectForUpdateSQL(java.lang.String astrSelectFragment)

Returns a simple SELECT statement with the appropriate phrases to include a previously read opt counter (if any) in the WHERE clause, and to obtain a FOR UPDATE lock.

The string returned is:

• astrSelectFragment + getWhereClauseFragment() + getSelectForUpdateFragment()

Do not call this method during static initialization.

Parameters:

astrSelectFragment - the select SQL fragment.

Returns:

the SQL statement.

setParameter

public OptCounterInfo setParameter(java.sql.PreparedStatement aPreparedStatement,
                                   int aIndex)
                            throws java.sql.SQLException

Sets the OPTCOUNTER value into the specified PreparedStatement at the specified position, if it is known and not null, has not been incremented, and has not been randomized.

Parameters:

aPreparedStatement - the PreparedStatement.

aIndex - the position of the parameter to be set in the PreparedStatement.

Returns:

this.

Throws:

java.sql.SQLException