java.lang.Object
- org.eclipse.persistence.queries.Cursor

All Implemented Interfaces:

Serializable, Enumeration, Iterator

Direct Known Subclasses:

CursoredStream, ScrollableCursor
```
public abstract class Cursor
extends Object
implements Enumeration, Iterator, Serializable
```
Purpose: Abstract class for CursoredStream and ScrolableCursor

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`protected AbstractSession`	`executionSession`	The root session that executed the call for the query.
`protected Vector<DatabaseField>`	`fields`	The fields expected in the result set.
`protected Map<Object,Object>`	`initiallyConformingIndex`	Conforming instances found in memory when building the result.
`protected AbstractRecord`	`nextRow`	Store the next row, for 1-m joining.
`protected List<Object>`	`objectCollection`	Internal collection of objects.
`CursorPolicy`	`policy`	Query policy that initialize the stream.
`protected int`	`position`	Current position in the objectCollection of the stream.
`ReadQuery`	`query`	Read query that initialize the stream.
`protected ResultSet`	`resultSet`	The result set (cursor) that holds the handle to the database that the results are read from.
`protected Expression`	`selectionCriteriaClone`	SelectionCriteria & translation row ready for incremental conforming.
`protected AbstractSession`	`session`	The session that executed the query for the stream.
`protected int`	`size`	Cached size of the stream.
`protected Statement`	`statement`	The preparedStatement that holds the handle to the database that the results are read from.
`protected AbstractRecord`	`translationRow`

Constructor Summary

Constructors
Constructor Description

Cursor()
INTERNAL: Default constructor.

Cursor(DatabaseCall call, CursorPolicy policy)
INTERNAL:

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`protected Object`	`buildAndRegisterObject(AbstractRecord row)`	INTERNAL: builds and registers an object from a row for cursors.
`void`	`clear()`	PUBLIC: Release all objects read in so far.
`void`	`close()`	PUBLIC: Closes the stream.
`protected void`	`finalize()`	Close in case not closed.
`DatabaseAccessor`	`getAccessor()`	INTERNAL: Return the accessor associated with the cursor.
`protected abstract int`	`getCursorSize()`	INTERNAL: Retrieve the size of the open cursor by executing a count on the same query as the cursor.
`AbstractSession`	`getExecutionSession()`	INTERNAL: Returns the session the underlying call was executed on.
`Vector<DatabaseField>`	`getFields()`	INTERNAL: Return the fields for the stream.
`Map<Object,Object>`	`getInitiallyConformingIndex()`	INTERNAL: Conforming instances found in memory when building the result.
`List<Object>`	`getObjectCollection()`	INTERNAL: Return the internal object collection that stores the objects.
`int`	`getPageSize()`	INTERNAL: Return the number of items to be faulted in for the stream.
`CursorPolicy`	`getPolicy()`	INTERNAL: Return the cursor policy.
`abstract int`	`getPosition()`	INTERNAL: Return the position of the stream inside the object collection.
`ReadQuery`	`getQuery()`	INTERNAL: Return the query associated with the stream.
`ResultSet`	`getResultSet()`	INTERNAL: Return the result set (cursor).
`Expression`	`getSelectionCriteriaClone()`	INTERNAL: The clone of the selection criteria is needed for in-memory conforming each object read from the Cursor.
`AbstractSession`	`getSession()`	INTERNAL: Return the handle to the session
`protected Statement`	`getStatement()`	INTERNAL: Return the Statement.
`protected AbstractRecord`	`getTranslationRow()`	INTERNAL: Gets the translation row the query was executed with, used for incremental conforming.
`boolean`	`isClosed()`	PUBLIC: Return if the stream is closed.
`void`	`remove()`	PUBLIC: Remove is not support with cursors.
`protected abstract Object`	`retrieveNextObject()`	INTERNAL: Read the next row from the result set.
`protected void`	`setExecutionSession(AbstractSession executionSession)`	INTERNAL: Sets the session the underlying call was executed on.
`protected void`	`setFields(Vector<DatabaseField> fields)`	INTERNAL: Set the fields for the stream.
`void`	`setInitiallyConformingIndex(Map<Object,Object> index)`	INTERNAL: Conforming instances found in memory when building the result.
`void`	`setObjectCollection(List<Object> collection)`	INTERNAL: Set the internal object collection
`void`	`setPolicy(CursorPolicy policy)`	INTERNAL: Set the cursor policy.
`protected void`	`setPosition(int value)`	INTERNAL: Set the current position of the stream
`protected void`	`setResultSet(ResultSet result)`	INTERNAL: Set the result set (cursor)
`void`	`setSelectionCriteriaClone(Expression expression)`	INTERNAL: The clone of the selection criteria is needed for in-memory conforming each object read from the Cursor.
`void`	`setSession(AbstractSession databaseSession)`	INTERNAL: Set the session handle
`void`	`setSize(int size)`	INTERNAL: Set the cache size
`void`	`setTranslationRow(AbstractRecord row)`	INTERNAL: Sets the translation row this query was executed with.
`int`	`size()`	PUBLIC: Retrieve the size of the open cursor by executing a count on the same query as the cursor.

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

Methods inherited from interface java.util.Enumeration
hasMoreElements, nextElement

Methods inherited from interface java.util.Iterator
forEachRemaining, hasNext, next

- Field Detail
  - statement
```
protected transient Statement statement
```
    The preparedStatement that holds the handle to the database that the results are read from.
  - resultSet
```
protected transient ResultSet resultSet
```
    The result set (cursor) that holds the handle to the database that the results are read from.
  - session
```
protected transient AbstractSession session
```
    The session that executed the query for the stream.
  - executionSession
```
protected transient AbstractSession executionSession
```
    The root session that executed the call for the query. Knows the database platform.
  - fields
```
protected transient Vector<DatabaseField> fields
```
    The fields expected in the result set.
  - size
```
protected int size
```
    Cached size of the stream.
  - query
```
public transient ReadQuery query
```
    Read query that initialize the stream.
  - policy
```
public transient CursorPolicy policy
```
    Query policy that initialize the stream.
  - objectCollection
```
protected List<Object> objectCollection
```
    Internal collection of objects.
  - initiallyConformingIndex
```
protected Map<Object,Object> initiallyConformingIndex
```
    Conforming instances found in memory when building the result.
  - selectionCriteriaClone
```
protected Expression selectionCriteriaClone
```
    SelectionCriteria & translation row ready for incremental conforming.
  - translationRow
```
protected AbstractRecord translationRow
```
  - nextRow
```
protected AbstractRecord nextRow
```
    Store the next row, for 1-m joining.
  - position
```
protected int position
```
    Current position in the objectCollection of the stream.
- Constructor Detail
  - Cursor
```
public Cursor()
```
    INTERNAL: Default constructor.
  - Cursor
```
public Cursor(DatabaseCall call,
              CursorPolicy policy)
```
    INTERNAL:
- Method Detail
  - close
```
public void close()
           throws DatabaseException
```
    PUBLIC: Closes the stream. This should be performed whenever the user has finished with the stream.
    
    Throws:
    
    DatabaseException
  - finalize
```
protected void finalize()
                 throws DatabaseException
```
    Close in case not closed.
    
    Overrides:
    
    finalize in class Object
    
    Throws:
    
    DatabaseException
  - getAccessor
```
public DatabaseAccessor getAccessor()
```
    INTERNAL: Return the accessor associated with the cursor.
  - getCursorSize
```
protected abstract int getCursorSize()
                              throws DatabaseException,
                                     QueryException
```
    INTERNAL: Retrieve the size of the open cursor by executing a count on the same query as the cursor.
    
    Throws:
    
    DatabaseException
    
    QueryException
  - getFields
```
public Vector<DatabaseField> getFields()
```
    INTERNAL: Return the fields for the stream.
  - getInitiallyConformingIndex
```
public Map<Object,Object> getInitiallyConformingIndex()
```
    INTERNAL: Conforming instances found in memory when building the result. These objects are returned first by the cursor, and a fast lookup is needed to make sure the same objects appearing in the cursor are filtered out.
  - getObjectCollection
```
public List<Object> getObjectCollection()
```
    INTERNAL: Return the internal object collection that stores the objects.
  - getPageSize
```
public int getPageSize()
```
    INTERNAL: Return the number of items to be faulted in for the stream.
  - getPolicy
```
public CursorPolicy getPolicy()
```
    INTERNAL: Return the cursor policy.
  - getPosition
```
public abstract int getPosition()
```
    INTERNAL: Return the position of the stream inside the object collection.
  - getQuery
```
public ReadQuery getQuery()
```
    INTERNAL: Return the query associated with the stream.
  - getResultSet
```
public ResultSet getResultSet()
```
    INTERNAL: Return the result set (cursor).
  - getSelectionCriteriaClone
```
public Expression getSelectionCriteriaClone()
```
    INTERNAL: The clone of the selection criteria is needed for in-memory conforming each object read from the Cursor.
  - getSession
```
public AbstractSession getSession()
```
    INTERNAL: Return the handle to the session
  - getExecutionSession
```
public AbstractSession getExecutionSession()
```
    INTERNAL: Returns the session the underlying call was executed on. This root session knows the database platform.
  - getStatement
```
protected Statement getStatement()
```
    INTERNAL: Return the Statement.
  - getTranslationRow
```
protected AbstractRecord getTranslationRow()
```
    INTERNAL: Gets the translation row the query was executed with, used for incremental conforming.
  - isClosed
```
public boolean isClosed()
```
    PUBLIC: Return if the stream is closed.
  - buildAndRegisterObject
```
protected Object buildAndRegisterObject(AbstractRecord row)
```
    INTERNAL: builds and registers an object from a row for cursors. Behavior is different from the query version in that refreshing is not supported.
  - retrieveNextObject
```
protected abstract Object retrieveNextObject()
                                      throws DatabaseException
```
    INTERNAL: Read the next row from the result set.
    
    Throws:
    
    DatabaseException
  - setFields
```
protected void setFields(Vector<DatabaseField> fields)
```
    INTERNAL: Set the fields for the stream.
  - setInitiallyConformingIndex
```
public void setInitiallyConformingIndex(Map<Object,Object> index)
```
    INTERNAL: Conforming instances found in memory when building the result. These objects are returned first by the cursor, and a fast lookup is needed to make sure the same objects appearing in the cursor are filtered out.
  - setObjectCollection
```
public void setObjectCollection(List<Object> collection)
```
    INTERNAL: Set the internal object collection
  - setPolicy
```
public void setPolicy(CursorPolicy policy)
```
    INTERNAL: Set the cursor policy.
  - setPosition
```
protected void setPosition(int value)
```
    INTERNAL: Set the current position of the stream
  - setResultSet
```
protected void setResultSet(ResultSet result)
```
    INTERNAL: Set the result set (cursor)
  - setSelectionCriteriaClone
```
public void setSelectionCriteriaClone(Expression expression)
```
    INTERNAL: The clone of the selection criteria is needed for in-memory conforming each object read from the Cursor.
  - setSession
```
public void setSession(AbstractSession databaseSession)
```
    INTERNAL: Set the session handle
  - setExecutionSession
```
protected void setExecutionSession(AbstractSession executionSession)
```
    INTERNAL: Sets the session the underlying call was executed on. This root session knows the database platform.
  - setSize
```
public void setSize(int size)
```
    INTERNAL: Set the cache size
  - setTranslationRow
```
public void setTranslationRow(AbstractRecord row)
```
    INTERNAL: Sets the translation row this query was executed with. Used for incremental conforming.
  - size
```
public int size()
         throws DatabaseException
```
    PUBLIC: Retrieve the size of the open cursor by executing a count on the same query as the cursor. If this cursor is conforming size() can only be an estimate. cursor size plus number of conforming instances found in memory will be returned. The union (actual result) may be smaller than this.
    
    Throws:
    
    DatabaseException
  - remove
```
public void remove()
            throws QueryException
```
    PUBLIC: Remove is not support with cursors.
    
    Specified by:
    
    remove in interface Iterator
    
    Throws:
    
    QueryException
  - clear
```
public void clear()
```
    PUBLIC: Release all objects read in so far. This should be performed when reading in a large collection of objects in order to preserve memory.

Constructor	Description
`Cursor()`	INTERNAL: Default constructor.
`Cursor(DatabaseCall call, CursorPolicy policy)`	INTERNAL:

Class Cursor

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Enumeration

Methods inherited from interface java.util.Iterator

Field Detail

statement

resultSet

session

executionSession

fields

size

query

policy

objectCollection

initiallyConformingIndex

selectionCriteriaClone

translationRow

nextRow

position

Constructor Detail

Cursor

Cursor

Method Detail

close

finalize

getAccessor

getCursorSize

getFields

getInitiallyConformingIndex

getObjectCollection

getPageSize

getPolicy

getPosition

getQuery

getResultSet

getSelectionCriteriaClone

getSession

getExecutionSession

getStatement

getTranslationRow

isClosed

buildAndRegisterObject

retrieveNextObject

setFields

setInitiallyConformingIndex

setObjectCollection

setPolicy

setPosition

setResultSet

setSelectionCriteriaClone

setSession

setExecutionSession

setSize

setTranslationRow

size

remove

clear