DEPRECATED Use `com.bea.p13n.util.jdbc.Sequencer``` and `com.bea.p13n.util.jdbc.SequencerFactory```

# com.beasys.commerce.util
JDBCSequencer Class

public class JDBCSequencer
extends `Object`
implements `com.beasys.commerce.util.Sequencer`

The JDBCSequencer class is a portable implementation for generating unique sequence numbers. JDBCSequencer uses a caching strategy where a block of sequence numbers is allocated in memory. When the block of sequence numbers is exhausted, JDBCSequencer obtains a new range of sequence numbers from the database. This approach has the advantage of minimizing the database access but it can create sequence numbers to be skipped if the server is restarted.

This implementation uses the WLCS_SEQUENCER table to maintain the current values of the different sequences. Each sequence is represented by a row in the WLCS_SEQUENCER and a row is automatically inserted for a sequence that does not exists already.

When allocating a new block of sequence numbers, JDBCSequencer uses a retry loop for obtaining an application lock (IS_LOCKED column in WLCS_SEQUENCER) before incrementing the current value of a sequence. Two properties can be defined in the weblogiccommerce.properties file to control the number of retries and the datasource name to use for obtaining a database connection:

- `commerce.jdbcSequencer.maxRetry` default value is 5 (1 second wait each retry)
- `commerce.jdbcSequencer.dataSource.name` default value is "weblogic.jdbc.jts.commercePool"

Note:JDBSequencer must run in WebLogic because it must suspend the current transaction when allocating a new block of sequence numbers.

Related Topics

``Sequencer``
``SequencerFactory``

Hierarchy
  `Object`
  `JDBCSequencer`

All Implemented Interfaces
  `com.beasys.commerce.util.Sequencer`

## Field Summary

`public static final long` | `DEFAULT_CACHE_SIZE` long
`public static final `String`` | `DEFAULT_SEQUENCE_NAME` String
`public static final `String`` | `DEFAULT_SEQUENCER_DATASOURCE_NAME` String
`public static final `String`` | `DEFAULT_SEQUENCER_NAME` String
`public static final long` | `DEFAULT_STEP_SIZE` long
`public static final `String`` | `SEQUENCE_LOCK_IDENTIFIER` String
`public static final `String`` | `SEQUENCE_NAME_IDENTIFIER` String
`public static final `String`` | `SEQUENCE_VALUE_IDENTIFIER` String
`public static final `String`` | `SEQUENCER_DATASOURCE_NAME_PROPERTY` String
`public static final `String`` | `SEQUENCER_MAX_RETRY_PROPERTY` String

## Constructor Summary

JDBCSequencer() Default constructor.
JDBCSequencer(`String` sequencerName, `String` sequenceName, long cacheSize, long stepSize) Creates a new `JDBCSequencer` with the supplied sequencer name, managed sequence name, cache size, and step size.
JDBCSequencer(`String` sequencerName, `String` sequenceName, long cacheSize) Creates a new `JDBCSequencer` with the supplied sequencer name, managed sequence name, and cache size.
JDBCSequencer(`String` sequencerName, `String` sequenceName) Creates a new `JDBCSequencer` with the supplied sequencer name and managed sequence name.

## Method Summary

`protected final void` | `allocateSequenceBlock`() Allocates a new block of sequence numbers from the database.
`protected final void` | `cleanUpResources`() Closes any open DB resources.
`public long` | `getCacheSize`() Returns the cache size.
`public long` | `getCurrent`(`Connection` databaseConnection) Gets the current sequence number associated with this sequencer.
`public long` | `getCurrent`() Gets the current sequence number associated with this sequencer.
`public long` | `getIncrementAmount`() Returns the increment amount.
`public long` | `getNext`(`Connection` databaseConnection) Gets the next sequence number using the supplied database connection.
`public long` | `getNext`() Gets the next sequence number.
`public `String`` | `getSequenceName`() Returns the name of the sequence that is managed by this sequencer.
`public `String`` | `getSequencerName`() Returns the name of this sequencer.
`public long` | `getStepSize`() Returns the step size.
`public void` | `setCacheSize`(long cacheSize) Sets the cache size.
`public void` | `setIncrementAmount`(long incrementAmount) Sets the increment amount.
`public void` | `setSequenceName`(`String` sequenceName) Sets the name of the sequence that is managed by this sequencer.
`public void` | `setSequencerName`(`String` sequencerName) Sets the name of this sequencer.
`public void` | `setStepSize`(long stepSize) Sets the step size.

Methods from class `java.lang.`Object``
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Methods from interface `com.beasys.commerce.util.`com.beasys.commerce.util.Sequencer``
``getCacheSize`, `getCurrent`, `getIncrementAmount`, `getNext`, `getSequenceName`, `getSequencerName`, `getStepSize`, `setCacheSize`, `setIncrementAmount`, `setSequenceName`, `setSequencerName`, `setStepSize``

## Field Detail

### DEFAULT_CACHE_SIZE

    public static final long DEFAULT_CACHE_SIZE

### DEFAULT_SEQUENCE_NAME

    public static final String DEFAULT_SEQUENCE_NAME

### DEFAULT_SEQUENCER_DATASOURCE_NAME

    public static final String DEFAULT_SEQUENCER_DATASOURCE_NAME

### DEFAULT_SEQUENCER_NAME

    public static final String DEFAULT_SEQUENCER_NAME

### DEFAULT_STEP_SIZE

    public static final long DEFAULT_STEP_SIZE

### SEQUENCE_LOCK_IDENTIFIER

    public static final String SEQUENCE_LOCK_IDENTIFIER

### SEQUENCE_NAME_IDENTIFIER

    public static final String SEQUENCE_NAME_IDENTIFIER

### SEQUENCE_VALUE_IDENTIFIER

    public static final String SEQUENCE_VALUE_IDENTIFIER

### SEQUENCER_DATASOURCE_NAME_PROPERTY

    public static final String SEQUENCER_DATASOURCE_NAME_PROPERTY

### SEQUENCER_MAX_RETRY_PROPERTY

    public static final String SEQUENCER_MAX_RETRY_PROPERTY

## Constructor Detail

### JDBCSequencer

    public JDBCSequencer()

  Default constructor.

### JDBCSequencer

    public JDBCSequencer(String sequencerName,
                         String sequenceName,
                         long cacheSize,
                         long stepSize)

  Creates a new `JDBCSequencer` with the supplied sequencer name, managed sequence name, cache size, and step size.

### JDBCSequencer

    public JDBCSequencer(String sequencerName,
                         String sequenceName,
                         long cacheSize)

  Creates a new `JDBCSequencer` with the supplied sequencer name, managed sequence name, and cache size.

### JDBCSequencer

    public JDBCSequencer(String sequencerName,
                         String sequenceName)

  Creates a new `JDBCSequencer` with the supplied sequencer name and managed sequence name.

## Method Detail

### allocateSequenceBlock() Method

    protected final void allocateSequenceBlock()
         throws SQLException

Allocates a new block of sequence numbers from the database. If a transaction is in progress, it is suspended during the database updates required for incrementing the current value of the sequence and resumed after.

#### Exceptions

``SQLException``

### cleanUpResources() Method

    protected final void cleanUpResources()

Closes any open DB resources.

### getCacheSize() Method

    public long getCacheSize()

Returns the cache size. The cache size defines how often the sequencer will allocate a block of unique sequence numbers from the database. When the sequencer exhausts its supplied of allocated numbers, it will allocate a new sequence of numbers from the database.

#### Returns

The cache size.

### getCurrent(Connection) Method

DEPRECATED JDBCSequencer must allocate the sequence block using a separate transaction because the database updates can be undone if a rollback occurs on the passed connection. Replaced by `com.beasys.commerce.util.JDBCSequencer.getNext()```

    public long getCurrent(Connection databaseConnection)
         throws SQLException

Gets the current sequence number associated with this sequencer.

#### Parameters

databaseConnection
  The database connection used to generate the next sequence number.

#### Exceptions

``SQLException``

### getCurrent() Method

    public long getCurrent()
         throws SQLException

Gets the current sequence number associated with this sequencer.

#### Exceptions

``SQLException``

### getIncrementAmount() Method

DEPRECATED Replaced by getCacheSize

    public long getIncrementAmount()

Returns the increment amount. The increment amount defines how often the sequencer will allocate a block of unique sequence numbers from the database. When the sequencer exhausts its supplied of allocated numbers, it will allocate a new sequence of numbers from the database.

#### Returns

The increment amount.

Related Topics

``JDBCSequencer.getCacheSize()``

### getNext(Connection) Method

DEPRECATED JDBCSequencer must allocate the sequence block using a separate transaction because the database updates can be undone if a rollback occurs on the passed connection. Replaced by `com.beasys.commerce.util.JDBCSequencer.getNext()```

    public long getNext(Connection databaseConnection)
         throws SQLException

Gets the next sequence number using the supplied database connection. The database connection will not be automatically closed upon method return. This class is thread safe.

#### Parameters

databaseConnection
  The database connection used to generate the next sequence number.

#### Exceptions

``SQLException``

### getNext() Method

    public long getNext()
         throws SQLException

Gets the next sequence number. A new block of sequence numbers is allocated if the cache of numbers is exhausted.

#### Returns

the next sequence number

#### Exceptions

``SQLException``

### getSequenceName() Method

    public String getSequenceName()

Returns the name of the sequence that is managed by this sequencer.

#### Returns

The sequence name.

### getSequencerName() Method

    public String getSequencerName()

Returns the name of this sequencer.

#### Returns

The sequencer name.

### getStepSize() Method

    public long getStepSize()

Returns the step size. The step size determines the difference between the values returned from successive calls to `getNext()`.

#### Returns

The step size.

### setCacheSize(long) Method

    public void setCacheSize(long cacheSize)

Sets the cache size. The cache size defines how often the sequencer will allocate a block of unique sequence numbers from the database. When the sequencer exhausts its supplied of allocated numbers, it will allocate a new sequence of numbers from the database.

#### Parameters

cacheSize
  The cache size.

### setIncrementAmount(long) Method

DEPRECATED Replaced by setCacheSize

    public void setIncrementAmount(long incrementAmount)

Sets the increment amount. The increment amount defines how often the sequencer will allocate a block of unique sequence numbers from the database. When the sequencer exhausts its supplied of allocated numbers, it will allocate a new sequence of numbers from the database.

#### Parameters

incrementAmount
  The increment amount.

Related Topics

``JDBCSequencer.setCacheSize(long)``

### setSequenceName(String) Method

    public void setSequenceName(String sequenceName)

Sets the name of the sequence that is managed by this sequencer.

#### Parameters

sequenceName
  The new sequence name.

### setSequencerName(String) Method

    public void setSequencerName(String sequencerName)

Sets the name of this sequencer.

#### Parameters

sequencerName
  The new sequencer name.

### setStepSize(long) Method

    public void setStepSize(long stepSize)

Sets the step size. The step size determines the difference between the values returned from successive calls to `getNext()`.

#### Parameters

stepSize
  The step size.