org.exist.xquery.update
Class Modification

java.lang.Object
  org.exist.xquery.AbstractExpression
      org.exist.xquery.update.Modification

All Implemented Interfaces:

Expression

Direct Known Subclasses:

Delete, Insert, Rename, Replace, Update

public abstract class Modification

extends AbstractExpression

Author:

wolf

Field Summary

protected DocumentSet	lockedDocuments
protected static Logger	LOG
protected Expression	select
protected Expression	value

Fields inherited from class org.exist.xquery.AbstractExpression

astNode, context, contextDocSet, contextId

Fields inherited from interface org.exist.xquery.Expression

EXPRESSION_ID_INVALID, IGNORE_CONTEXT, IN_PREDICATE, IN_UPDATE, IN_WHERE_CLAUSE, NO_CONTEXT_ID, SINGLE_STEP_EXECUTION

Constructor Summary

Modification(XQueryContext context, Expression select, Expression value)

Method Summary

void	analyze(AnalyzeContextInfo contextInfo) Statically analyze the expression and its subexpressions.
protected void	checkFragmentation(Txn transaction, DocumentSet docs) Check if any of the modified documents needs defragmentation.
protected Sequence	deepCopy(Sequence inSeq)
int	getCardinality() The default cardinality is Cardinality.EXACTLY_ONE.
void	resetState() Called to inform an expression that it should reset to its initial state.
int	returnsType() The static return type of the expression.
protected StoredNode[]	selectAndLock(NodeSet nodes) Acquire a lock on all documents processed by this modification.
protected void	unlockDocuments() Release all acquired document locks.

Methods inherited from class org.exist.xquery.AbstractExpression

eval, eval, getASTNode, getContextDocSet, getContextId, getDependencies, getExpressionId, setASTNode, setContextDocSet, setPrimaryAxis

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.exist.xquery.Expression

dump

Field Detail

LOG

protected static final Logger LOG

select

protected final Expression select

value

protected final Expression value

lockedDocuments

protected DocumentSet lockedDocuments

Constructor Detail

Modification

public Modification(XQueryContext context,
                    Expression select,
                    Expression value)

Parameters:

context -

Method Detail

getCardinality

public int getCardinality()

Description copied from class: AbstractExpression

The default cardinality is Cardinality.EXACTLY_ONE.

Specified by:

getCardinality in interface Expression

Overrides:

getCardinality in class AbstractExpression

returnsType

public int returnsType()

Description copied from interface: Expression

The static return type of the expression. This method should return one of the type constants defined in class Type. If the return type cannot be determined statically, return Type.ITEM.

Specified by:

returnsType in interface Expression

Specified by:

returnsType in class AbstractExpression

resetState

public void resetState()

Description copied from interface: Expression

Called to inform an expression that it should reset to its initial state. All cached data in the expression object should be dropped. For example, the document() function calls this method whenever the input document set has changed.

Specified by:

resetState in interface Expression

Overrides:

resetState in class AbstractExpression

analyze

public void analyze(AnalyzeContextInfo contextInfo)
             throws XPathException

Description copied from interface: Expression

Statically analyze the expression and its subexpressions. During the static analysis phase, the query engine can detect unknown variables and some type errors.

Throws:

XPathException

selectAndLock

protected StoredNode[] selectAndLock(NodeSet nodes)
                              throws LockException,
                                     PermissionDeniedException,
                                     XPathException

Acquire a lock on all documents processed by this modification. We have to avoid that node positions change during the operation.

Returns:

Throws:

LockException

PermissionDeniedException

XPathException

deepCopy

protected Sequence deepCopy(Sequence inSeq)
                     throws XPathException

Throws:

XPathException

unlockDocuments

protected void unlockDocuments()

Release all acquired document locks.

checkFragmentation

protected void checkFragmentation(Txn transaction,
                                  DocumentSet docs)
                           throws EXistException

Check if any of the modified documents needs defragmentation. Defragmentation will take place if the number of split pages in the document exceeds the limit defined in the configuration file.

Parameters:

docs -

Throws:

EXistException