Module org.eclipse.persistence.core
Package org.eclipse.persistence.sequencing

Class Sequence

java.lang.Object
org.eclipse.persistence.sequencing.Sequence
All Implemented Interfaces:
Serializable, Cloneable
Direct Known Subclasses:
DefaultSequence, OIDSequence, StandardSequence, UUIDSequence
public abstract class Sequence extends Object implements Serializable, 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:

  • Field Details

    • name

      protected String name

    • size

      protected int size

    • platform

      protected Platform platform

    • initialValue

      protected int initialValue

    • depth

      protected int depth

    • qualifier

      protected String qualifier

    • isCustomQualifier

      protected boolean isCustomQualifier

    • shouldAlwaysOverrideExistingValue

      protected boolean shouldAlwaysOverrideExistingValue

  • Constructor Details

    • Sequence

      protected Sequence()

    • Sequence

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

    • Sequence

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

    • Sequence

      protected Sequence(String name, int size, int initialValue)

  • Method Details

    • isNative

      public boolean isNative()

    • isTable

      public boolean isTable()

    • isUnaryTable

      public boolean isUnaryTable()

    • getName

      public String getName()

    • setName

      public void setName(String name)

    • getPreallocationSize

      public int getPreallocationSize()

    • setPreallocationSize

      public void setPreallocationSize(int size)

    • getInitialValue

      public int getInitialValue()

    • setInitialValue

      public void setInitialValue(int initialValue)

    • clone

      public Object clone()
      Overrides:
      clone in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • equalNameAndSize

      public static boolean equalNameAndSize(Sequence seq1, Sequence seq2)
      INTERNAL: Used in equals.

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • setDatasourcePlatform

      protected void setDatasourcePlatform(Platform platform)

    • getDatasourcePlatform

      public 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 Object getGeneratedValue(Accessor accessor, AbstractSession writeSession, 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 Object getGeneratedValue(Accessor accessor, 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 Vector<?> getGeneratedVector(Accessor accessor, AbstractSession writeSession, 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 Vector<?> getGeneratedVector(Accessor accessor, 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(Platform platform)
      INTERNAL: This method is called when Sequencing object is created. Don't override this method.

    • onConnect

      public 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(Platform platform)
      INTERNAL: This method is called when Sequencing object is destroyed. Don't override this method.

    • onDisconnect

      public 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(Platform otherPlatform)
      INTERNAL: Make sure that the sequence is not used by more than one platform.

    • setQualifier

      public void setQualifier(String qualifier)
      INTERNAL:

    • isCustomQualifier

      public boolean isCustomQualifier()
      INTERNAL:

    • getQualifier

      public String getQualifier()
      INTERNAL:

    • getQualified

      public String getQualified(String str)
      INTERNAL:

    • setShouldAlwaysOverrideExistingValue

      public void setShouldAlwaysOverrideExistingValue(boolean shouldAlwaysOverrideExistingValue)
      ADVANCED: Set that to true if the sequence should always override the existing pk value.

    • shouldAlwaysOverrideExistingValue

      public boolean shouldAlwaysOverrideExistingValue()
      INTERNAL: Indicates whether the existing pk value should always be overridden by the sequence. As always the version of the method taking seqName is provided for the benefit of DefaultSequence.

    • shouldAlwaysOverrideExistingValue

      public boolean shouldAlwaysOverrideExistingValue(String seqName)
      INTERNAL: Indicates whether the existing pk value should always be overridden by the sequence.

    • toString

      public String toString()
      Overrides:
      toString in class Object