net.sf.saxon.expr

Class SystemFunctionCall.Optimized

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.FunctionCall

net.sf.saxon.expr.StaticFunctionCall

net.sf.saxon.expr.SystemFunctionCall

net.sf.saxon.expr.SystemFunctionCall.Optimized

All Implemented Interfaces:

Callable, ExportAgent, Locatable, Negatable, IdentityComparable

Enclosing class:

SystemFunctionCall

public abstract static class SystemFunctionCall.Optimized
extends SystemFunctionCall

Subclass representing a system function call that has been optimized; this overrides the optimize() method to do nothing, thus ensuring that optimization converges.

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.saxon.expr.SystemFunctionCall

SystemFunctionCall.Optimized

Field Summary

Fields inherited from class net.sf.saxon.expr.SystemFunctionCall

argumentEvaluators

Fields inherited from class net.sf.saxon.expr.Expression

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_COST, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD

Constructor Summary

Constructors

Constructor and Description
Optimized(SystemFunction target, Expression[] arguments)

Method Summary

Modifier and Type	Method and Description
Expression	optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) Perform optimisation of an expression and its subexpressions.

Methods inherited from class net.sf.saxon.expr.SystemFunctionCall

addToPathMap, computeCardinality, computeSpecialProperties, copy, evaluateArguments, export, getExpressionName, getIntegerBounds, getIntrinsicDependencies, getItemType, getNetCost, getScopingExpression, getTargetFunction, isLiftable, isNegatable, isVacuousExpression, negate, preEvaluate, resetLocalStaticProperties, setRetainedStaticContext, toPattern, typeCheck, unordered

Methods inherited from class net.sf.saxon.expr.StaticFunctionCall

call, getFunctionName, getStaticUType, getTargetFunction, isCallOn

Methods inherited from class net.sf.saxon.expr.FunctionCall

addExternalFunctionCallToPathMap, adjustRequiredType, checkArgumentCount, checkArguments, checkFunctionCall, computeHashCode, equals, getArg, getArguments, getArity, getDisplayName, getImplementationMethod, getOperanda, iterate, operands, pluralArguments, preEvaluateIfConstant, setArg, setArguments, setOperanda, setOperanda, simplifyArguments, toShortString, toString

Methods inherited from class net.sf.saxon.expr.Expression

adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getConstructType, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getInterpretedExpression, getLocalRetainedStaticContext, getLocation, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStreamerName, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isEqual, isIdentical, isInstruction, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, prepareForStreaming, process, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, typeCheckChildren, typeError, verifyParentPointers

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Optimized

public Optimized(SystemFunction target,
                 Expression[] arguments)

Method Detail

optimize

public Expression optimize(ExpressionVisitor visitor,
                           ContextItemStaticInfo contextInfo)
                    throws XPathException

Description copied from class: FunctionCall

Perform optimisation of an expression and its subexpressions.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

Overrides:

optimize in class SystemFunctionCall

Parameters:

visitor - an expression visitor

contextInfo - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE

Returns:

the original expression, rewritten if appropriate to optimize execution

Throws:

XPathException - if an error is discovered during this phase (typically a type error)