Package org.eclipse.persistence.queries
Class Cursor
- java.lang.Object
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- org.eclipse.persistence.queries.Cursor
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- 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
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Field Summary
Fields Modifier and Type Field Description CursorPolicy
policy
Query policy that initialize the stream.ReadQuery
query
Read query that initialize the stream.
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Constructor Summary
Constructors Constructor Description Cursor()
INTERNAL: Default constructor.Cursor(org.eclipse.persistence.internal.databaseaccess.DatabaseCall call, CursorPolicy policy)
INTERNAL:
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description void
clear()
PUBLIC: Release all objects read in so far.void
close()
PUBLIC: Closes the stream.org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor
getAccessor()
INTERNAL: Return the accessor associated with the cursor.org.eclipse.persistence.internal.sessions.AbstractSession
getExecutionSession()
INTERNAL: Returns the session the underlying call was executed on.Vector<org.eclipse.persistence.internal.helper.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.org.eclipse.persistence.internal.sessions.AbstractSession
getSession()
INTERNAL: Return the handle to the sessionboolean
isClosed()
PUBLIC: Return if the stream is closed.void
remove()
PUBLIC: Remove is not support with cursors.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 collectionvoid
setPolicy(CursorPolicy policy)
INTERNAL: Set the cursor policy.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(org.eclipse.persistence.internal.sessions.AbstractSession databaseSession)
INTERNAL: Set the session handlevoid
setSize(int size)
INTERNAL: Set the cache sizevoid
setTranslationRow(org.eclipse.persistence.internal.sessions.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
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface java.util.Enumeration
asIterator, hasMoreElements, nextElement
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Methods inherited from interface java.util.Iterator
forEachRemaining, hasNext, next
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Field Detail
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query
public transient ReadQuery query
Read query that initialize the stream.
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policy
public transient CursorPolicy policy
Query policy that initialize the stream.
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Constructor Detail
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Cursor
public Cursor()
INTERNAL: Default constructor.
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Cursor
public Cursor(org.eclipse.persistence.internal.databaseaccess.DatabaseCall call, CursorPolicy policy)
INTERNAL:
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Method Detail
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close
public void close() throws DatabaseException
PUBLIC: Closes the stream. This should be performed whenever the user has finished with the stream.- Throws:
DatabaseException
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getAccessor
public org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor getAccessor()
INTERNAL: Return the accessor associated with the cursor.
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getFields
public Vector<org.eclipse.persistence.internal.helper.DatabaseField> getFields()
INTERNAL: Return the fields for the stream.
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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.
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getObjectCollection
public List<Object> getObjectCollection()
INTERNAL: Return the internal object collection that stores the objects.
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getPageSize
public int getPageSize()
INTERNAL: Return the number of items to be faulted in for the stream.
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getPolicy
public CursorPolicy getPolicy()
INTERNAL: Return the cursor policy.
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getPosition
public abstract int getPosition()
INTERNAL: Return the position of the stream inside the object collection.
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getQuery
public ReadQuery getQuery()
INTERNAL: Return the query associated with the stream.
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getResultSet
public ResultSet getResultSet()
INTERNAL: Return the result set (cursor).
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getSelectionCriteriaClone
public Expression getSelectionCriteriaClone()
INTERNAL: The clone of the selection criteria is needed for in-memory conforming each object read from the Cursor.
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getSession
public org.eclipse.persistence.internal.sessions.AbstractSession getSession()
INTERNAL: Return the handle to the session
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getExecutionSession
public org.eclipse.persistence.internal.sessions.AbstractSession getExecutionSession()
INTERNAL: Returns the session the underlying call was executed on. This root session knows the database platform.
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isClosed
public boolean isClosed()
PUBLIC: Return if the stream is closed.
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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.
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setObjectCollection
public void setObjectCollection(List<Object> collection)
INTERNAL: Set the internal object collection
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setPolicy
public void setPolicy(CursorPolicy policy)
INTERNAL: Set the cursor policy.
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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.
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setSession
public void setSession(org.eclipse.persistence.internal.sessions.AbstractSession databaseSession)
INTERNAL: Set the session handle
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setSize
public void setSize(int size)
INTERNAL: Set the cache size
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setTranslationRow
public void setTranslationRow(org.eclipse.persistence.internal.sessions.AbstractRecord row)
INTERNAL: Sets the translation row this query was executed with. Used for incremental conforming.
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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
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remove
public void remove() throws QueryException
PUBLIC: Remove is not support with cursors.- Specified by:
remove
in interfaceIterator
- Throws:
QueryException
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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.
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