org.cdlib.xtf.saxonExt
Class InstructionWithContent

Object
  Expression
      Instruction
          InstructionWithContent

All Implemented Interfaces:

Serializable, SourceLocator, Container, EvaluableItem, SequenceIterable, TailCallReturner, InstructionInfoProvider

Direct Known Subclasses:

OutputElement.OutputInstruction, PipeFileElement.PipeFileInstruction, PipeFopElement.PipeFopInstruction, PipeRequestElement.PipeRequestInstruction, SendElement.SendInstruction

public abstract class InstructionWithContent
extends Instruction

Base class that automates much of the tedious Saxon housekeeping for an extension instruction that supports arbitrary content.

Author:

Martin Haye

See Also:

Serialized Form

Field Summary

protected Map<String,Expression>	attribs
protected Expression	content
protected String	name
private int	nameCode

Fields inherited from class Expression

EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

InstructionWithContent(String name, Map<String,Expression> attribs, Expression content)
Construct the content instruction.

Method Summary

boolean	createsNewNodes() Determine whether this instruction creates new nodes.
void	display(int level, PrintStream out, Configuration config) Diagnostic print of expression structure.
protected void	dynamicError(Throwable cause, String message, String code, XPathContext context) Special version of dynamicError that includes a cause with the exception.
boolean	getAttribBool(String attrName, XPathContext context, boolean defaultVal)
String	getAttribStr(String attrName, XPathContext context)
String	getAttribStr(String attrName, XPathContext context, String defaultVal)
int	getCardinality()
int	getInstructionNameCode() Get the name of this instruction for diagnostic and tracing purposes
ItemType	getItemType(TypeHierarchy th)
Iterator	iterateSubExpressions() Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)
Expression	optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
abstract TailCall	processLeavingTail(XPathContext context) This is where the main work should be performed.
protected void	promoteInst(PromotionOffer offer) Handle promotion offers, that is, non-local tree rewrites.
boolean	replaceSubExpression(Expression original, Expression replacement) Replace one subexpression by a replacement subexpression
protected static String	sequenceToString(Expression exp, XPathContext context) Utility function to convert an expression (which might be a sequence) to a string value.
Expression	simplify(StaticContext env) Simplify an expression.
Expression	typeCheck(StaticContext env, ItemType contextItemType)

Methods inherited from class Instruction

appendItem, assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getImplementationMethod, getInstructionInfo, getSourceLocator, isXSLT, iterate, process, promote

Methods inherited from class Expression

adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, getColumnNumber, getConstructType, getContainingProcedure, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, typeError

Methods inherited from class Object

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

Methods inherited from interface SourceLocator

getColumnNumber, getLineNumber, getPublicId, getSystemId

Field Detail

name

protected final String name

nameCode

private int nameCode

attribs

protected Map<String,Expression> attribs

content

protected Expression content

Constructor Detail

InstructionWithContent

public InstructionWithContent(String name,
                              Map<String,Expression> attribs,
                              Expression content)

Construct the content instruction.

Method Detail

getAttribStr

public String getAttribStr(String attrName,
                           XPathContext context)
                    throws XPathException

Throws:

XPathException

getAttribStr

public String getAttribStr(String attrName,
                           XPathContext context,
                           String defaultVal)
                    throws XPathException

Throws:

XPathException

getAttribBool

public boolean getAttribBool(String attrName,
                             XPathContext context,
                             boolean defaultVal)
                      throws XPathException

Throws:

XPathException

simplify

public Expression simplify(StaticContext env)
                    throws XPathException

Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.

Specified by:

simplify in class Instruction

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

typeCheck

public Expression typeCheck(StaticContext env,
                            ItemType contextItemType)
                     throws XPathException

Overrides:

typeCheck in class Expression

Throws:

XPathException

optimize

public Expression optimize(Optimizer opt,
                           StaticContext env,
                           ItemType contextItemType)
                    throws XPathException

Overrides:

optimize in class Expression

Throws:

XPathException

getInstructionNameCode

public int getInstructionNameCode()

Get the name of this instruction for diagnostic and tracing purposes

Overrides:

getInstructionNameCode in class Instruction

getItemType

public ItemType getItemType(TypeHierarchy th)

Overrides:

getItemType in class Instruction

getCardinality

public int getCardinality()

Overrides:

getCardinality in class Expression

createsNewNodes

public final boolean createsNewNodes()

Determine whether this instruction creates new nodes. This implementation returns true.

Overrides:

createsNewNodes in class Instruction

promoteInst

protected void promoteInst(PromotionOffer offer)
                    throws XPathException

Handle promotion offers, that is, non-local tree rewrites.

Overrides:

promoteInst in class Instruction

Parameters:

offer - The type of rewrite being offered

Throws:

XPathException

iterateSubExpressions

public Iterator iterateSubExpressions()

Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)

Overrides:

iterateSubExpressions in class Expression

replaceSubExpression

public boolean replaceSubExpression(Expression original,
                                    Expression replacement)

Replace one subexpression by a replacement subexpression

Specified by:

replaceSubExpression in interface Container

Overrides:

replaceSubExpression in class Expression

Parameters:

original - the original subexpression

replacement - the replacement subexpression

Returns:

true if the original subexpression is found

processLeavingTail

public abstract TailCall processLeavingTail(XPathContext context)
                                     throws XPathException

This is where the main work should be performed. Subclasses must implement this method.

Specified by:

processLeavingTail in interface TailCallReturner

Specified by:

processLeavingTail in class Instruction

Throws:

XPathException

sequenceToString

protected static String sequenceToString(Expression exp,
                                         XPathContext context)
                                  throws XPathException

Utility function to convert an expression (which might be a sequence) to a string value.

Throws:

XPathException

display

public void display(int level,
                    PrintStream out,
                    Configuration config)

Diagnostic print of expression structure. The expression is written to the System.err output stream

Specified by:

display in class Expression

Parameters:

level - indentation level for this expression

out -

config -

dynamicError

protected void dynamicError(Throwable cause,
                            String message,
                            String code,
                            XPathContext context)
                     throws DynamicError

Special version of dynamicError that includes a cause with the exception.

Throws:

DynamicError