EclipseLink Core 4.0.2 · org.eclipse.persistence.history.AsOfClause

Purpose:Wraps an immutable value for a past time. A session, query, or expression can be as of a past time.

For Oracle 9R2 Flasback corresponds to the sub clause which appears between the table and alias name in the FROM clause: SELECT ... FROM EMPLOYEE AS OF TIMESTAMP (value) t0, ...

For generic historical schema support, a special criteria can be added to the where clause for each table in a select: ((t0.ROW_START <= value) AND ((t0.END IS NULL) OR (t1.END > value)))

Responsibilities:

By default AsOfClause is a timestamp. To specify a system change number use AsOfSCNClause.
For Oracle 9R2 Flashback prints the correct AS OF clause before the alias name in the FROM clause.
Read-only: the wrapped value can not change.

Field Summary

Modifier and Type	Field and Description
public static final AsOfClause	NO_CLAUSE
private Object	value

Constructor Summary

Access	Constructor and Description
protected	AsOfClause()
public	AsOfClause(Date date)
public	AsOfClause(Timestamp timestamp)
public	AsOfClause(Calendar calendar)
public	AsOfClause(long time)
public	AsOfClause(Long time)
protected	AsOfClause(Number number)
public	AsOfClause(Expression expression)
protected	AsOfClause(AsOfClause wrappedValue)

Method Summary

Modifier and Type	Method and Description
public boolean	equals(Object the reference object with which to compare. object) Overrides java.lang.Object.equals. INTERNAL: Return if the as of is equal to the other.
public Object	getValue() PUBLIC: The past time represented by the receiver.
public boolean	isAsOfSCNClause() PUBLIC: Indicates that `value` is a system change number or an expression evaluating to one.
public boolean	isUniversal() PUBLIC: Answers if this is a UniversalAsOfClause, one to be applied to the entire selection criteria.
public void	printSQL(ExpressionSQLPrinter printer) INTERNAL: Prints the as of clause for an expression inside of the FROM clause.
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.

Inherited from java.lang.Object:: clone finalize getClass hashCode notify notifyAll wait wait wait

Field Detail

NO_CLAUSE	back to summary
public static final AsOfClause NO_CLAUSE

value	back to summary
private Object value

Constructor Detail

AsOfClause	back to summary
protected AsOfClause()

AsOfClause	back to summary
public AsOfClause(Date date)

AsOfClause	back to summary
public AsOfClause(Timestamp timestamp)

AsOfClause	back to summary
public AsOfClause(Calendar calendar)

AsOfClause	back to summary
public AsOfClause(long time)

AsOfClause	back to summary
public AsOfClause(Long time)

AsOfClause	back to summary
protected AsOfClause(Number number)

AsOfClause	back to summary
public AsOfClause(Expression expression)

AsOfClause	back to summary
protected AsOfClause(AsOfClause wrappedValue)

Method Detail

equals back to summary

equals	back to summary
public boolean equals(Object object) Overrides java.lang.Object.equals. INTERNAL: Return if the as of is equal to the other. Equality of asOf clauses is complex (with subclasses), so only use identity. Parameters object:Object Doc from java.lang.Object.equals. the reference object with which to compare. Returns:boolean Doc from java.lang.Object.equals. `true` if this object is the same as the obj argument; `false` otherwise. Annotations @Override

public boolean equals(Object object)

Overrides java.lang.Object.equals.

INTERNAL: Return if the as of is equal to the other. Equality of asOf clauses is complex (with subclasses), so only use identity.

Parameters

object:Object

Doc from java.lang.Object.equals.

the reference object with which to compare.

Returns:boolean

Doc from java.lang.Object.equals.

true if this object is the same as the obj argument; false otherwise.

Annotations

@Override

getValue	back to summary
public Object getValue() PUBLIC: The past time represented by the receiver. Either a timestamp, a system change number, or an Expression.

isAsOfSCNClause back to summary

isAsOfSCNClause	back to summary
public boolean isAsOfSCNClause() PUBLIC: Indicates that `value` is a system change number or an expression evaluating to one. In Oracle the value will have to be printed using the syntax `AS OF SCN(value)` instead of `AS OF TIMESTAMP(value)`. See Also `AsOfSCNClause`

public boolean isAsOfSCNClause()

PUBLIC: Indicates that value is a system change number or an expression evaluating to one.

In Oracle the value will have to be printed using the syntax AS OF SCN(value) instead of AS OF TIMESTAMP(value).

See Also: AsOfSCNClause

isUniversal	back to summary
public boolean isUniversal() PUBLIC: Answers if this is a UniversalAsOfClause, one to be applied to the entire selection criteria. Used when a query is made as of a past time.

isUniversal

back to summary

public boolean isUniversal()

PUBLIC: Answers if this is a UniversalAsOfClause, one to be applied to the entire selection criteria.

Used when a query is made as of a past time.

printSQL	back to summary
public void printSQL(ExpressionSQLPrinter printer) INTERNAL: Prints the as of clause for an expression inside of the FROM clause.

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Doc from java.lang.Object.toString. Returns a string representation of the object. Returns:String a string representation of the object. Annotations @Override

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object.