org.eclipse.persistence.sequencing
Class Sequence

java.lang.Object
  org.eclipse.persistence.sequencing.Sequence

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

Direct Known Subclasses:

DefaultSequence, StandardSequence

public abstract class Sequence
extends java.lang.Object
implements java.io.Serializable, java.lang.Cloneable

Purpose: Abstract class to define sequencing.

Description A sequence defines how generated ids are obtained. The main sequence types are TableSequence and NativeSequence. Descriptors using sequencing will use the sequence object defined in their session's DatabaseLogin with the name matching their sequence name. If a specific sequence is not defined for the name the DatabaseLogin's default sequence will be used.

See Also:

TableSequence, NativeSequence, Serialized Form

Field Summary

protected int	depth
protected int	initialValue
protected java.lang.String	name
protected org.eclipse.persistence.internal.databaseaccess.Platform	platform
protected int	size

Constructor Summary

Sequence()

Sequence(java.lang.String name)
Create a new sequence with the name.

Sequence(java.lang.String name, int size)
Create a new sequence with the name and sequence pre-allocation size.

Sequence(java.lang.String name, int size, int initialValue)

Method Summary

java.lang.Object	clone()
static boolean	equalNameAndSize(Sequence seq1, Sequence seq2) INTERNAL: Used in equals.
boolean	equals(java.lang.Object obj)
org.eclipse.persistence.internal.databaseaccess.Platform	getDatasourcePlatform()
java.lang.Object	getGeneratedValue(org.eclipse.persistence.internal.databaseaccess.Accessor accessor, org.eclipse.persistence.internal.sessions.AbstractSession writeSession) INTERNAL: Return the newly-generated sequencing value.
abstract java.lang.Object	getGeneratedValue(org.eclipse.persistence.internal.databaseaccess.Accessor accessor, org.eclipse.persistence.internal.sessions.AbstractSession writeSession, java.lang.String seqName) INTERNAL: Return the newly-generated sequencing value.
java.util.Vector	getGeneratedVector(org.eclipse.persistence.internal.databaseaccess.Accessor accessor, org.eclipse.persistence.internal.sessions.AbstractSession writeSession) INTERNAL: Return a Vector of newly-generated sequencing values.
abstract java.util.Vector	getGeneratedVector(org.eclipse.persistence.internal.databaseaccess.Accessor accessor, org.eclipse.persistence.internal.sessions.AbstractSession writeSession, java.lang.String seqName, int size) INTERNAL: Return a Vector of newly-generated sequencing values.
int	getInitialValue()
java.lang.String	getName()
int	getPreallocationSize()
boolean	isConnected() PUBLIC: Indicates that Sequence is connected.
boolean	isNative()
boolean	isTable()
boolean	isUnaryTable()
protected abstract void	onConnect() INTERNAL: This method is called when Sequencing object is created.
void	onConnect(org.eclipse.persistence.internal.databaseaccess.Platform platform) INTERNAL: This method is called when Sequencing object is created.
protected abstract void	onDisconnect() INTERNAL: This method is called when Sequencing object is destroyed.
void	onDisconnect(org.eclipse.persistence.internal.databaseaccess.Platform platform) INTERNAL: This method is called when Sequencing object is destroyed.
protected void	setDatasourcePlatform(org.eclipse.persistence.internal.databaseaccess.Platform platform)
void	setInitialValue(int initialValue)
void	setName(java.lang.String name)
void	setPreallocationSize(int size)
abstract boolean	shouldAcquireValueAfterInsert() INTERNAL: Indicates whether sequencing value should be acquired after INSERT.
boolean	shouldUsePreallocation() INTERNAL: Indicates whether several sequencing values should be acquired at a time and be kept by TopLink.
abstract boolean	shouldUseTransaction() INTERNAL: Indicates whether TopLink should internally call beginTransaction() before getGeneratedValue/Vector, and commitTransaction after.
protected void	verifyPlatform(org.eclipse.persistence.internal.databaseaccess.Platform otherPlatform) INTERNAL: Make sure that the sequence is not used by more than one platform.

Methods inherited from class java.lang.Object

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

Field Detail

name

protected java.lang.String name

size

protected int size

platform

protected org.eclipse.persistence.internal.databaseaccess.Platform platform

initialValue

protected int initialValue

depth

protected int depth

Constructor Detail

Sequence

public Sequence()

Sequence

public Sequence(java.lang.String name)

Create a new sequence with the name.

Sequence

public Sequence(java.lang.String name,
                int size)

Create a new sequence with the name and sequence pre-allocation size.

Sequence

public Sequence(java.lang.String name,
                int size,
                int initialValue)

Method Detail

isNative

public boolean isNative()

isTable

public boolean isTable()

isUnaryTable

public boolean isUnaryTable()

getName

public java.lang.String getName()

setName

public void setName(java.lang.String name)

getPreallocationSize

public int getPreallocationSize()

setPreallocationSize

public void setPreallocationSize(int size)

getInitialValue

public int getInitialValue()

setInitialValue

public void setInitialValue(int initialValue)

clone

public java.lang.Object clone()

Overrides:

clone in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

equalNameAndSize

public static boolean equalNameAndSize(Sequence seq1,
                                       Sequence seq2)

INTERNAL: Used in equals.

setDatasourcePlatform

protected void setDatasourcePlatform(org.eclipse.persistence.internal.databaseaccess.Platform platform)

getDatasourcePlatform

public org.eclipse.persistence.internal.databaseaccess.Platform getDatasourcePlatform()

shouldAcquireValueAfterInsert

public abstract boolean shouldAcquireValueAfterInsert()

INTERNAL: Indicates whether sequencing value should be acquired after INSERT. Note that preallocation could be used only in case sequencing values should be acquired before insert (this method returns false). In default implementation, it is true for table sequencing and native sequencing on Oracle platform, false for native sequencing on other platforms.

shouldUsePreallocation

public boolean shouldUsePreallocation()

INTERNAL: Indicates whether several sequencing values should be acquired at a time and be kept by TopLink. This in only possible in case sequencing numbers should be acquired before insert (shouldAcquireValueAfterInsert()==false). In default implementation, it is true for table sequencing and native sequencing on Oracle platform, false for native sequencing on other platforms.

shouldUseTransaction

public abstract boolean shouldUseTransaction()

INTERNAL: Indicates whether TopLink should internally call beginTransaction() before getGeneratedValue/Vector, and commitTransaction after. In default implementation, it is true for table sequencing and false for native sequencing.

getGeneratedValue

public abstract java.lang.Object getGeneratedValue(org.eclipse.persistence.internal.databaseaccess.Accessor accessor,
                                                   org.eclipse.persistence.internal.sessions.AbstractSession writeSession,
                                                   java.lang.String seqName)

INTERNAL: Return the newly-generated sequencing value. Used only in case preallocation is not used (shouldUsePreallocation()==false). Accessor may be non-null only in case shouldUseSeparateConnection()==true. Even in this case accessor could be null - if SequencingControl().shouldUseSeparateConnection()==false; Therefore in case shouldUseSeparateConnection()==true, implementation should handle both cases: use a separate connection if provided (accessor != null), or get by without it (accessor == null).

Parameters:

accessor - Accessor is a separate sequencing accessor (may be null);

writeSession - Session is a Session used for writing (either ClientSession or DatabaseSession);

seqName - String is sequencing number field name

getGeneratedValue

public java.lang.Object getGeneratedValue(org.eclipse.persistence.internal.databaseaccess.Accessor accessor,
                                          org.eclipse.persistence.internal.sessions.AbstractSession writeSession)

INTERNAL: Return the newly-generated sequencing value. Used only in case preallocation is not used (shouldUsePreallocation()==false). Accessor may be non-null only in case shouldUseSeparateConnection()==true. Even in this case accessor could be null - if SequencingControl().shouldUseSeparateConnection()==false; Therefore in case shouldUseSeparateConnection()==true, implementation should handle both cases: use a separate connection if provided (accessor != null), or get by without it (accessor == null).

Parameters:

accessor - Accessor is a separate sequencing accessor (may be null);

writeSession - Session is a Session used for writing (either ClientSession or DatabaseSession);

getGeneratedVector

public abstract java.util.Vector getGeneratedVector(org.eclipse.persistence.internal.databaseaccess.Accessor accessor,
                                                    org.eclipse.persistence.internal.sessions.AbstractSession writeSession,
                                                    java.lang.String seqName,
                                                    int size)

INTERNAL: Return a Vector of newly-generated sequencing values. Used only in case preallocation is used (shouldUsePreallocation()==true). Accessor may be non-null only in case shouldUseSeparateConnection()==true. Even in this case accessor could be null - if SequencingControl().shouldUseSeparateConnection()==false; Therefore in case shouldUseSeparateConnection()==true, implementation should handle both cases: use a separate connection if provided (accessor != null), or get by without it (accessor == null).

Parameters:

accessor - Accessor is a separate sequencing accessor (may be null);

writeSession - Session is a Session used for writing (either ClientSession or DatabaseSession);

seqName - String is sequencing number field name

size - int number of values to preallocate (output Vector size).

getGeneratedVector

public java.util.Vector getGeneratedVector(org.eclipse.persistence.internal.databaseaccess.Accessor accessor,
                                           org.eclipse.persistence.internal.sessions.AbstractSession writeSession)

INTERNAL: Return a Vector of newly-generated sequencing values. Used only in case preallocation is used (shouldUsePreallocation()==true). Accessor may be non-null only in case shouldUseSeparateConnection()==true. Even in this case accessor could be null - if SequencingControl().shouldUseSeparateConnection()==false; Therefore in case shouldUseSeparateConnection()==true, implementation should handle both cases: use a separate connection if provided (accessor != null), or get by without it (accessor == null).

Parameters:

accessor - Accessor is a separate sequencing accessor (may be null);

writeSession - Session is a Session used for writing (either ClientSession or DatabaseSession);

onConnect

public void onConnect(org.eclipse.persistence.internal.databaseaccess.Platform platform)

INTERNAL: This method is called when Sequencing object is created. Don't override this method.

onConnect

protected abstract void onConnect()

INTERNAL: This method is called when Sequencing object is created. If it requires initialization, subclass should override this method.

onDisconnect

public void onDisconnect(org.eclipse.persistence.internal.databaseaccess.Platform platform)

INTERNAL: This method is called when Sequencing object is destroyed. Don't override this method.

onDisconnect

protected abstract void onDisconnect()

INTERNAL: This method is called when Sequencing object is destroyed. If it requires deinitialization, subclass should override this method.

isConnected

public boolean isConnected()

PUBLIC: Indicates that Sequence is connected.

verifyPlatform

protected void verifyPlatform(org.eclipse.persistence.internal.databaseaccess.Platform otherPlatform)

INTERNAL: Make sure that the sequence is not used by more than one platform.