Package net.sf.saxon.instruct

Class CopyOf

    • Constructor Detail

      • CopyOf

        public CopyOf​(Expression select,
              boolean copyNamespaces,
              int validation,
              SchemaType schemaType,
              boolean rejectDuplicatAttributes)

    • Method Detail

      • setReadOnce

        public void setReadOnce​(boolean b)

      • createsNewNodes

        public final boolean createsNewNodes()
        Determine whether this instruction creates new nodes. The result depends on the type of the select expression.
        Overrides:
        createsNewNodes in class Instruction

      • getInstructionNameCode

        public int getInstructionNameCode()
        Get the name of this instruction, for diagnostics and tracing
        Overrides:
        getInstructionNameCode in class Instruction

      • setRequireDocumentOrElement

        public void setRequireDocumentOrElement​(boolean requireDocumentOrElement)
        For XQuery, the operand (select) must be a single element or document node.
        Parameters:
        requireDocumentOrElement -

      • getImplementationMethod

        public int getImplementationMethod()
        An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided. This implementation provides both iterate() and process() methods natively.
        Specified by:
        getImplementationMethod in interface Expression
        Overrides:
        getImplementationMethod in class Instruction

      • copyAttribute

        static void copyAttribute​(NodeInfo source,
                          SchemaType schemaType,
                          int validation,
                          Instruction instruction,
                          XPathContext context,
                          boolean rejectDuplicates)
                   throws XPathException
        Method shared by xsl:copy and xsl:copy-of to copy an attribute node
        Parameters:
        source - the node to be copied
        schemaType - the simple type against which the value is to be validated, if any
        validation - one of preserve, strip, strict, lax
        instruction - the calling instruction, used for diagnostics
        context - the dynamic context
        rejectDuplicates - true if duplicate attributes with the same name are disallowed (XQuery)
        Throws:
        XPathException

      • simplify

        public Expression simplify​(StaticContext env)
                    throws XPathException
        Description copied from class: Instruction
        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 interface Expression
        Specified by:
        simplify in class Instruction
        Parameters:
        env - the static context
        Returns:
        the simplified expression
        Throws:
        XPathException - if an error is discovered during expression rewriting

      • getCardinality

        public int getCardinality()
        Description copied from class: ComputedExpression
        Determine the static cardinality of the expression. This establishes how many items there will be in the result of the expression, at compile time (i.e., without actually evaluating the result.
        Specified by:
        getCardinality in interface Expression
        Overrides:
        getCardinality in class ComputedExpression
        Returns:
        one of the values Cardinality.ONE_OR_MORE, Cardinality.ZERO_OR_MORE, Cardinality.EXACTLY_ONE, Cardinality.ZERO_OR_ONE, Cardinality.EMPTY. This default implementation returns ZERO_OR_MORE (which effectively gives no information).

      • getDependencies

        public int getDependencies()
        Description copied from class: ComputedExpression
        Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as XPathContext.VARIABLES and XPathContext.CURRENT_NODE. The default implementation combines the intrinsic dependencies of this expression with the dependencies of the subexpressions, computed recursively. This is overridden for expressions such as FilterExpression where a subexpression's dependencies are not necessarily inherited by the parent expression.
        Specified by:
        getDependencies in interface Expression
        Overrides:
        getDependencies in class ComputedExpression
        Returns:
        a set of bit-significant flags identifying the dependencies of the expression

      • typeCheck

        public Expression typeCheck​(StaticContext env,
                            ItemType contextItemType)
                     throws XPathException
        Description copied from interface: Expression
        Perform type checking of an expression and its subexpressions. This is the second phase of static optimization.

        This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.

        This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.

        If the implementation returns a value other than "this", then it is required to ensure that the parent pointer and location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.

        Parameters:
        env - the static context of the expression
        contextItemType - 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 to perform necessary run-time type checks, and to perform other type-related optimizations
        Throws:
        StaticError - if an error is discovered during this phase (typically a type error)
        XPathException

      • optimize

        public Expression optimize​(Optimizer opt,
                           StaticContext env,
                           ItemType contextItemType)
                    throws XPathException
        Description copied from interface: Expression
        Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization.

        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.

        Parameters:
        opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.
        env - the static context of the expression
        contextItemType - 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:
        StaticError - if an error is discovered during this phase (typically a type error)
        XPathException

      • display

        public void display​(int level,
                    java.io.PrintStream out,
                    Configuration config)
        Diagnostic print of expression structure. The expression is written to the System.err output stream
        Parameters:
        level - indentation level for this expression
        out -
        config -

      • iterateSubExpressions

        public java.util.Iterator iterateSubExpressions()
        Description copied from class: ComputedExpression
        Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.
        Specified by:
        iterateSubExpressions in interface Expression
        Overrides:
        iterateSubExpressions in class ComputedExpression
        Returns:
        an iterator containing the sub-expressions of this 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 ComputedExpression
        Parameters:
        original - the original subexpression
        replacement - the replacement subexpression
        Returns:
        true if the original subexpression is found

      • iterate

        public SequenceIterator iterate​(XPathContext context)
                         throws XPathException
        Description copied from class: Instruction
        Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.
        Specified by:
        iterate in interface Expression
        Overrides:
        iterate in class Instruction
        Parameters:
        context - supplies the context for evaluation
        Returns:
        a SequenceIterator that can be used to iterate over the result of the expression
        Throws:
        XPathException - if any dynamic error occurs evaluating the expression