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SimpleExpression
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net.sf.saxon.expr</FONT>
<BR>
Class SimpleExpression</H2>
<PRE>
<A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">java.lang.Object</A>
<IMG SRC="../../../../resources/inherit.gif" ALT="extended by "><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">net.sf.saxon.expr.Expression</A>
<IMG SRC="../../../../resources/inherit.gif" ALT="extended by "><B>net.sf.saxon.expr.SimpleExpression</B>
</PRE>
<DL>
<DT><B>All Implemented Interfaces:</B> <DD><A HREF="http://download.oracle.com/javase/6/docs/api/java/io/Serializable.html?is-external=true" title="class or interface in java.io">Serializable</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/javax/xml/transform/SourceLocator.html?is-external=true" title="class or interface in javax.xml.transform">SourceLocator</A>, <A HREF="../../../../net/sf/saxon/event/LocationProvider.html" title="interface in net.sf.saxon.event">LocationProvider</A>, <A HREF="../../../../net/sf/saxon/event/SaxonLocator.html" title="interface in net.sf.saxon.event">SaxonLocator</A>, <A HREF="../../../../net/sf/saxon/expr/CallableExpression.html" title="interface in net.sf.saxon.expr">CallableExpression</A>, <A HREF="../../../../net/sf/saxon/trace/InstructionInfo.html" title="interface in net.sf.saxon.trace">InstructionInfo</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/org/xml/sax/Locator.html?is-external=true" title="class or interface in org.xml.sax">Locator</A></DD>
</DL>
<DL>
<DT><B>Direct Known Subclasses:</B> <DD><A HREF="../../../../com/saxonica/expr/ContextCall.html" title="class in com.saxonica.expr">ContextCall</A></DD>
</DL>
<HR>
<DL>
<DT><PRE>public abstract class <B>SimpleExpression</B><DT>extends <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A><DT>implements <A HREF="../../../../net/sf/saxon/expr/CallableExpression.html" title="interface in net.sf.saxon.expr">CallableExpression</A></DL>
</PRE>
<P>
An abstract implementation of Expression designed to make it easy to implement new expressions,
in particular, expressions to support extension instructions.
<p>An implementation of this class must supply the <A HREF="../../../../net/sf/saxon/expr/CallableExpression.html#call(net.sf.saxon.om.SequenceIterator[], net.sf.saxon.expr.XPathContext)"><CODE>CallableExpression.call(net.sf.saxon.om.SequenceIterator[], XPathContext)</CODE></A>
method to evaluate the expression and return its result.</p>
<P>
<P>
<DL>
<DT><B>See Also:</B><DD><A HREF="../../../../serialized-form.html#net.sf.saxon.expr.SimpleExpression">Serialized Form</A></DL>
<HR>
<P>
<!-- =========== FIELD SUMMARY =========== -->
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<B>Field Summary</B></FONT></TH>
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<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>protected <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>[]</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#arguments">arguments</A></B></CODE>
<BR>
</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>static <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>[]</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#NO_ARGUMENTS">NO_ARGUMENTS</A></B></CODE>
<BR>
</TD>
</TR>
</TABLE>
<A NAME="fields_inherited_from_class_net.sf.saxon.expr.Expression"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TH ALIGN="left"><B>Fields inherited from class net.sf.saxon.expr.<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></B></TH>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#EFFECTIVE_BOOLEAN_VALUE">EFFECTIVE_BOOLEAN_VALUE</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#EVALUATE_METHOD">EVALUATE_METHOD</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#EVENT_FEED_METHOD">EVENT_FEED_METHOD</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#ITEM_FEED_METHOD">ITEM_FEED_METHOD</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#ITERATE_METHOD">ITERATE_METHOD</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#locationId">locationId</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#MAX_SEQUENCE_LENGTH">MAX_SEQUENCE_LENGTH</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#MAX_STRING_LENGTH">MAX_STRING_LENGTH</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#PROCESS_METHOD">PROCESS_METHOD</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#PUSH_SELECTION">PUSH_SELECTION</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#staticProperties">staticProperties</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#UNBOUNDED_LOWER">UNBOUNDED_LOWER</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#UNBOUNDED_UPPER">UNBOUNDED_UPPER</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#WATCH_METHOD">WATCH_METHOD</A></CODE></TD>
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<!-- ======== CONSTRUCTOR SUMMARY ======== -->
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<B>Constructor Summary</B></FONT></TH>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#SimpleExpression()">SimpleExpression</A></B>()</CODE>
<BR>
Constructor</TD>
</TR>
</TABLE>
<!-- ========== METHOD SUMMARY =========== -->
<A NAME="method_summary"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
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<B>Method Summary</B></FONT></TH>
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<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#computeCardinality()">computeCardinality</A></B>()</CODE>
<BR>
Determine the static cardinality of the expression.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#computeDependencies()">computeDependencies</A></B>()</CODE>
<BR>
Compute the dependencies of an expression, as the union of the
dependencies of its subexpressions.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#copy()">copy</A></B>()</CODE>
<BR>
Copy an expression.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../../net/sf/saxon/om/Item.html" title="interface in net.sf.saxon.om">Item</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#evaluateItem(net.sf.saxon.expr.XPathContext)">evaluateItem</A></B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A> context)</CODE>
<BR>
Evaluate an expression as a single item.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#explain(net.sf.saxon.trace.ExpressionPresenter)">explain</A></B>(<A HREF="../../../../net/sf/saxon/trace/ExpressionPresenter.html" title="class in net.sf.saxon.trace">ExpressionPresenter</A> destination)</CODE>
<BR>
Diagnostic print of expression structure.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>[]</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#getArguments()">getArguments</A></B>()</CODE>
<BR>
Get the subexpressions (arguments to this expression)</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#getExpressionType()">getExpressionType</A></B>()</CODE>
<BR>
Return a distinguishing name for the expression, for use in diagnostics.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../../net/sf/saxon/type/ItemType.html" title="interface in net.sf.saxon.type">ItemType</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#getItemType(net.sf.saxon.type.TypeHierarchy)">getItemType</A></B>(<A HREF="../../../../net/sf/saxon/type/TypeHierarchy.html" title="class in net.sf.saxon.type">TypeHierarchy</A> th)</CODE>
<BR>
Determine the data type of the items returned by this expression.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../../net/sf/saxon/om/SequenceIterator.html" title="interface in net.sf.saxon.om">SequenceIterator</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#iterate(net.sf.saxon.expr.XPathContext)">iterate</A></B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A> context)</CODE>
<BR>
Return an Iterator to iterate over the values of a sequence.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="http://download.oracle.com/javase/6/docs/api/java/util/Iterator.html?is-external=true" title="class or interface in java.util">Iterator</A><<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#iterateSubExpressions()">iterateSubExpressions</A></B>()</CODE>
<BR>
Get the immediate sub-expressions of this expression.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#optimize(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)">optimize</A></B>(<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor</A> visitor,
<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.ContextItemType.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor.ContextItemType</A> contextItemType)</CODE>
<BR>
Perform optimisation of an expression and its subexpressions.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#process(net.sf.saxon.expr.XPathContext)">process</A></B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A> context)</CODE>
<BR>
Process the instruction, without returning any tail calls</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#promote(net.sf.saxon.expr.parser.PromotionOffer, net.sf.saxon.expr.Expression)">promote</A></B>(<A HREF="../../../../net/sf/saxon/expr/parser/PromotionOffer.html" title="class in net.sf.saxon.expr.parser">PromotionOffer</A> offer,
<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> parent)</CODE>
<BR>
Offer promotion for this subexpression.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> boolean</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#replaceSubExpression(net.sf.saxon.expr.Expression, net.sf.saxon.expr.Expression)">replaceSubExpression</A></B>(<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> original,
<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> replacement)</CODE>
<BR>
Replace one subexpression by a replacement subexpression</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#setArguments(net.sf.saxon.expr.Expression[])">setArguments</A></B>(<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>[] sub)</CODE>
<BR>
Set the immediate sub-expressions of this expression.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#simplify(net.sf.saxon.expr.parser.ExpressionVisitor)">simplify</A></B>(<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor</A> visitor)</CODE>
<BR>
Simplify the expression</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE> <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SimpleExpression.html#typeCheck(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)">typeCheck</A></B>(<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor</A> visitor,
<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.ContextItemType.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor.ContextItemType</A> contextItemType)</CODE>
<BR>
Perform type checking of an expression and its subexpressions.</TD>
</TR>
</TABLE>
<A NAME="methods_inherited_from_class_net.sf.saxon.expr.Expression"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TH ALIGN="left"><B>Methods inherited from class net.sf.saxon.expr.<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></B></TH>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#addToPathMap(net.sf.saxon.expr.parser.PathMap, net.sf.saxon.expr.parser.PathMap.PathMapNodeSet)">addToPathMap</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#adoptChildExpression(net.sf.saxon.expr.Expression)">adoptChildExpression</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#checkForUpdatingSubexpressions()">checkForUpdatingSubexpressions</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#checkPermittedContents(net.sf.saxon.type.SchemaType, net.sf.saxon.expr.StaticContext, boolean)">checkPermittedContents</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#computeSpecialProperties()">computeSpecialProperties</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#computeStaticProperties()">computeStaticProperties</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#doPromotion(net.sf.saxon.expr.Expression, net.sf.saxon.expr.parser.PromotionOffer)">doPromotion</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#dynamicError(java.lang.String, java.lang.String, net.sf.saxon.expr.XPathContext)">dynamicError</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#effectiveBooleanValue(net.sf.saxon.expr.XPathContext)">effectiveBooleanValue</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#evaluateAsString(net.sf.saxon.expr.XPathContext)">evaluateAsString</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#evaluatePendingUpdates(net.sf.saxon.expr.XPathContext, net.sf.saxon.expr.PendingUpdateList)">evaluatePendingUpdates</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#explain(java.io.OutputStream)">explain</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getCardinality()">getCardinality</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getColumnNumber()">getColumnNumber</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getColumnNumber(long)">getColumnNumber</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getConstructType()">getConstructType</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getContainer()">getContainer</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getDependencies()">getDependencies</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getEvaluationMethod()">getEvaluationMethod</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getExecutable()">getExecutable</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getExpressionName()">getExpressionName</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getHostLanguage()">getHostLanguage</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getImplementationMethod()">getImplementationMethod</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getIntegerBounds()">getIntegerBounds</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getIntrinsicDependencies()">getIntrinsicDependencies</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getLineNumber()">getLineNumber</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getLineNumber(long)">getLineNumber</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getLocationId()">getLocationId</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getLocationProvider()">getLocationProvider</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getObjectName()">getObjectName</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getProperties()">getProperties</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getProperty(java.lang.String)">getProperty</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getPublicId()">getPublicId</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getSlotsUsed()">getSlotsUsed</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getSpecialProperties()">getSpecialProperties</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getSystemId()">getSystemId</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#getSystemId(long)">getSystemId</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#hasLoopingSubexpression(net.sf.saxon.expr.Expression)">hasLoopingSubexpression</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#hasVariableBinding(net.sf.saxon.expr.Binding)">hasVariableBinding</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#implementsStaticTypeCheck()">implementsStaticTypeCheck</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#isSubtreeExpression()">isSubtreeExpression</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#isUpdatingExpression()">isUpdatingExpression</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#isVacuousExpression()">isVacuousExpression</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#iterateEvents(net.sf.saxon.expr.XPathContext)">iterateEvents</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#iterateSameFocusSubExpressions()">iterateSameFocusSubExpressions</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#markTailFunctionCalls(net.sf.saxon.om.StructuredQName, int)">markTailFunctionCalls</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#resetLocalStaticProperties()">resetLocalStaticProperties</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#setContainer(net.sf.saxon.expr.Container)">setContainer</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#setEvaluationMethod(int)">setEvaluationMethod</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#setFiltered(boolean)">setFiltered</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#setFlattened(boolean)">setFlattened</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#setLocationId(int)">setLocationId</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#staticTypeCheck(net.sf.saxon.value.SequenceType, boolean, net.sf.saxon.expr.parser.RoleLocator, net.sf.saxon.TypeCheckerEnvironment)">staticTypeCheck</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#suppressValidation(int)">suppressValidation</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#toString()">toString</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#typeError(java.lang.String, java.lang.String, net.sf.saxon.expr.XPathContext)">typeError</A></CODE></TD>
</TR>
</TABLE>
<A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TH ALIGN="left"><B>Methods inherited from class java.lang.<A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</A></B></TH>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#clone()" title="class or interface in java.lang">clone</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#equals(java.lang.Object)" title="class or interface in java.lang">equals</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#finalize()" title="class or interface in java.lang">finalize</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#getClass()" title="class or interface in java.lang">getClass</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#hashCode()" title="class or interface in java.lang">hashCode</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#notify()" title="class or interface in java.lang">notify</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#notifyAll()" title="class or interface in java.lang">notifyAll</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait()" title="class or interface in java.lang">wait</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait(long)" title="class or interface in java.lang">wait</A>, <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/Object.html?is-external=true#wait(long, int)" title="class or interface in java.lang">wait</A></CODE></TD>
</TR>
</TABLE>
<A NAME="methods_inherited_from_class_net.sf.saxon.expr.CallableExpression"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TH ALIGN="left"><B>Methods inherited from interface net.sf.saxon.expr.<A HREF="../../../../net/sf/saxon/expr/CallableExpression.html" title="interface in net.sf.saxon.expr">CallableExpression</A></B></TH>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="../../../../net/sf/saxon/expr/CallableExpression.html#call(net.sf.saxon.om.SequenceIterator[], net.sf.saxon.expr.XPathContext)">call</A></CODE></TD>
</TR>
</TABLE>
<P>
<!-- ============ FIELD DETAIL =========== -->
<A NAME="field_detail"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
<B>Field Detail</B></FONT></TH>
</TR>
</TABLE>
<A NAME="NO_ARGUMENTS"><!-- --></A><H3>
NO_ARGUMENTS</H3>
<PRE>
public static final <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>[] <B>NO_ARGUMENTS</B></PRE>
<DL>
<DL>
</DL>
</DL>
<HR>
<A NAME="arguments"><!-- --></A><H3>
arguments</H3>
<PRE>
protected <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>[] <B>arguments</B></PRE>
<DL>
<DL>
</DL>
</DL>
<!-- ========= CONSTRUCTOR DETAIL ======== -->
<A NAME="constructor_detail"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
<B>Constructor Detail</B></FONT></TH>
</TR>
</TABLE>
<A NAME="SimpleExpression()"><!-- --></A><H3>
SimpleExpression</H3>
<PRE>
public <B>SimpleExpression</B>()</PRE>
<DL>
<DD>Constructor
<P>
</DL>
<!-- ============ METHOD DETAIL ========== -->
<A NAME="method_detail"><!-- --></A>
<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
<B>Method Detail</B></FONT></TH>
</TR>
</TABLE>
<A NAME="setArguments(net.sf.saxon.expr.Expression[])"><!-- --></A><H3>
setArguments</H3>
<PRE>
public void <B>setArguments</B>(<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>[] sub)</PRE>
<DL>
<DD>Set the immediate sub-expressions of this expression.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>sub</CODE> - an array containing the sub-expressions of this expression</DL>
</DD>
</DL>
<HR>
<A NAME="iterateSubExpressions()"><!-- --></A><H3>
iterateSubExpressions</H3>
<PRE>
public <A HREF="http://download.oracle.com/javase/6/docs/api/java/util/Iterator.html?is-external=true" title="class or interface in java.util">Iterator</A><<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>> <B>iterateSubExpressions</B>()</PRE>
<DL>
<DD>Get the immediate sub-expressions of this expression.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#iterateSubExpressions()">iterateSubExpressions</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>an array containing the sub-expressions of this expression</DL>
</DD>
</DL>
<HR>
<A NAME="replaceSubExpression(net.sf.saxon.expr.Expression, net.sf.saxon.expr.Expression)"><!-- --></A><H3>
replaceSubExpression</H3>
<PRE>
public boolean <B>replaceSubExpression</B>(<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> original,
<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> replacement)</PRE>
<DL>
<DD>Replace one subexpression by a replacement subexpression
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#replaceSubExpression(net.sf.saxon.expr.Expression, net.sf.saxon.expr.Expression)">replaceSubExpression</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>original</CODE> - the original subexpression<DD><CODE>replacement</CODE> - the replacement subexpression
<DT><B>Returns:</B><DD>true if the original subexpression is found</DL>
</DD>
</DL>
<HR>
<A NAME="simplify(net.sf.saxon.expr.parser.ExpressionVisitor)"><!-- --></A><H3>
simplify</H3>
<PRE>
public <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> <B>simplify</B>(<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor</A> visitor)
throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Simplify the expression
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#simplify(net.sf.saxon.expr.parser.ExpressionVisitor)">simplify</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>visitor</CODE> - an expression visitor
<DT><B>Returns:</B><DD>the simplified expression
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if an error is discovered during expression
rewriting</DL>
</DD>
</DL>
<HR>
<A NAME="typeCheck(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)"><!-- --></A><H3>
typeCheck</H3>
<PRE>
public <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> <B>typeCheck</B>(<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor</A> visitor,
<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.ContextItemType.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor.ContextItemType</A> contextItemType)
throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD><B>Description copied from class: <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#typeCheck(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)">Expression</A></CODE></B></DD>
<DD>Perform type checking of an expression and its subexpressions. This is the second phase of
static optimization.
<p>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.</p>
<p>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.</p>
<p>If the implementation returns a value other than "this", then it is required to ensure that
the 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.</p>
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#typeCheck(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)">typeCheck</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>visitor</CODE> - an expression visitor<DD><CODE>contextItemType</CODE> - 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
<A HREF="../../../../net/sf/saxon/type/Type.html#ITEM_TYPE"><CODE>Type.ITEM_TYPE</CODE></A>
<DT><B>Returns:</B><DD>the original expression, rewritten to perform necessary run-time type checks,
and to perform other type-related optimizations
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if an error is discovered during this phase
(typically a type error)</DL>
</DD>
</DL>
<HR>
<A NAME="optimize(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)"><!-- --></A><H3>
optimize</H3>
<PRE>
public <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> <B>optimize</B>(<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor</A> visitor,
<A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.ContextItemType.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor.ContextItemType</A> contextItemType)
throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD><B>Description copied from class: <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#optimize(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)">Expression</A></CODE></B></DD>
<DD>Perform optimisation of an expression and its subexpressions. This is the third and final
phase of static optimization.
<p>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.</p>
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#optimize(net.sf.saxon.expr.parser.ExpressionVisitor, net.sf.saxon.expr.parser.ExpressionVisitor.ContextItemType)">optimize</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>visitor</CODE> - an expression visitor<DD><CODE>contextItemType</CODE> - 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
<A HREF="../../../../net/sf/saxon/type/Type.html#ITEM_TYPE"><CODE>Type.ITEM_TYPE</CODE></A>
<DT><B>Returns:</B><DD>the original expression, rewritten if appropriate to optimize execution
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if an error is discovered during this phase
(typically a type error)</DL>
</DD>
</DL>
<HR>
<A NAME="copy()"><!-- --></A><H3>
copy</H3>
<PRE>
public <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> <B>copy</B>()</PRE>
<DL>
<DD>Copy an expression. This makes a deep copy.
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#copy()">copy</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the copy of the original expression</DL>
</DD>
</DL>
<HR>
<A NAME="promote(net.sf.saxon.expr.parser.PromotionOffer, net.sf.saxon.expr.Expression)"><!-- --></A><H3>
promote</H3>
<PRE>
public <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> <B>promote</B>(<A HREF="../../../../net/sf/saxon/expr/parser/PromotionOffer.html" title="class in net.sf.saxon.expr.parser">PromotionOffer</A> offer,
<A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A> parent)
throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Offer promotion for this subexpression. The offer will be accepted if the subexpression
is not dependent on the factors (e.g. the context item) identified in the PromotionOffer.
By default the offer is not accepted - this is appropriate in the case of simple expressions
such as constant values and variable references where promotion would give no performance
advantage. This method is always called at compile time.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#promote(net.sf.saxon.expr.parser.PromotionOffer, net.sf.saxon.expr.Expression)">promote</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>offer</CODE> - details of the offer, for example the offer to move
expressions that don't depend on the context to an outer level in
the containing expression<DD><CODE>parent</CODE> -
<DT><B>Returns:</B><DD>if the offer is not accepted, return this expression unchanged.
Otherwise return the result of rewriting the expression to promote
this subexpression
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if any error is detected</DL>
</DD>
</DL>
<HR>
<A NAME="getItemType(net.sf.saxon.type.TypeHierarchy)"><!-- --></A><H3>
getItemType</H3>
<PRE>
public <A HREF="../../../../net/sf/saxon/type/ItemType.html" title="interface in net.sf.saxon.type">ItemType</A> <B>getItemType</B>(<A HREF="../../../../net/sf/saxon/type/TypeHierarchy.html" title="class in net.sf.saxon.type">TypeHierarchy</A> th)</PRE>
<DL>
<DD>Determine the data type of the items returned by this expression. This implementation
returns "item()", which can be overridden in a subclass.
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#getItemType(net.sf.saxon.type.TypeHierarchy)">getItemType</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>th</CODE> - the type hierarchy cache
<DT><B>Returns:</B><DD>the data type</DL>
</DD>
</DL>
<HR>
<A NAME="computeCardinality()"><!-- --></A><H3>
computeCardinality</H3>
<PRE>
public int <B>computeCardinality</B>()</PRE>
<DL>
<DD>Determine the static cardinality of the expression. This implementation
returns "zero or more", which can be overridden in a subclass.
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#computeCardinality()">computeCardinality</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the computed cardinality, as one of the values <A HREF="../../../../net/sf/saxon/expr/StaticProperty.html#ALLOWS_ZERO_OR_ONE"><CODE>StaticProperty.ALLOWS_ZERO_OR_ONE</CODE></A>,
<A HREF="../../../../net/sf/saxon/expr/StaticProperty.html#EXACTLY_ONE"><CODE>StaticProperty.EXACTLY_ONE</CODE></A>, <A HREF="../../../../net/sf/saxon/expr/StaticProperty.html#ALLOWS_ONE_OR_MORE"><CODE>StaticProperty.ALLOWS_ONE_OR_MORE</CODE></A>,
<A HREF="../../../../net/sf/saxon/expr/StaticProperty.html#ALLOWS_ZERO_OR_MORE"><CODE>StaticProperty.ALLOWS_ZERO_OR_MORE</CODE></A></DL>
</DD>
</DL>
<HR>
<A NAME="computeDependencies()"><!-- --></A><H3>
computeDependencies</H3>
<PRE>
public int <B>computeDependencies</B>()</PRE>
<DL>
<DD>Compute the dependencies of an expression, as the union of the
dependencies of its subexpressions. (This is overridden for path expressions
and filter expressions, where the dependencies of a subexpression are not all
propogated). This method should be called only once, to compute the dependencies;
after that, getDependencies should be used.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#computeDependencies()">computeDependencies</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the depencies, as a bit-mask</DL>
</DD>
</DL>
<HR>
<A NAME="evaluateItem(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
evaluateItem</H3>
<PRE>
public final <A HREF="../../../../net/sf/saxon/om/Item.html" title="interface in net.sf.saxon.om">Item</A> <B>evaluateItem</B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A> context)
throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Evaluate an expression as a single item. This always returns either a single Item or
null (denoting the empty sequence). No conversion is done. This method should not be
used unless the static type of the expression is a subtype of "item" or "item?": that is,
it should not be called if the expression may return a sequence. There is no guarantee that
this condition will be detected.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#evaluateItem(net.sf.saxon.expr.XPathContext)">evaluateItem</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - The context in which the expression is to be evaluated
<DT><B>Returns:</B><DD>the node or atomic value that results from evaluating the
expression; or null to indicate that the result is an empty
sequence
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if any dynamic error occurs evaluating the
expression</DL>
</DD>
</DL>
<HR>
<A NAME="iterate(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
iterate</H3>
<PRE>
public final <A HREF="../../../../net/sf/saxon/om/SequenceIterator.html" title="interface in net.sf.saxon.om">SequenceIterator</A> <B>iterate</B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A> context)
throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>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.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#iterate(net.sf.saxon.expr.XPathContext)">iterate</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - supplies the context for evaluation
<DT><B>Returns:</B><DD>a SequenceIterator that can be used to iterate over the result
of the expression
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if any dynamic error occurs evaluating the
expression</DL>
</DD>
</DL>
<HR>
<A NAME="process(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
process</H3>
<PRE>
public final void <B>process</B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A> context)
throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Process the instruction, without returning any tail calls
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#process(net.sf.saxon.expr.XPathContext)">process</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>context</CODE> - The dynamic context, giving access to the current node,
the current variables, etc.
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE> - if a dynamic error occurs</DL>
</DD>
</DL>
<HR>
<A NAME="getArguments()"><!-- --></A><H3>
getArguments</H3>
<PRE>
public <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A>[] <B>getArguments</B>()</PRE>
<DL>
<DD>Get the subexpressions (arguments to this expression)
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/CallableExpression.html#getArguments()">getArguments</A></CODE> in interface <CODE><A HREF="../../../../net/sf/saxon/expr/CallableExpression.html" title="interface in net.sf.saxon.expr">CallableExpression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>the arguments, as an array</DL>
</DD>
</DL>
<HR>
<A NAME="explain(net.sf.saxon.trace.ExpressionPresenter)"><!-- --></A><H3>
explain</H3>
<PRE>
public void <B>explain</B>(<A HREF="../../../../net/sf/saxon/trace/ExpressionPresenter.html" title="class in net.sf.saxon.trace">ExpressionPresenter</A> destination)</PRE>
<DL>
<DD>Diagnostic print of expression structure. The abstract expression tree
is written to the supplied output destination.
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#explain(net.sf.saxon.trace.ExpressionPresenter)">explain</A></CODE> in class <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>destination</CODE> - the expression presenter used to display the structure</DL>
</DD>
</DL>
<HR>
<A NAME="getExpressionType()"><!-- --></A><H3>
getExpressionType</H3>
<PRE>
public <A HREF="http://download.oracle.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A> <B>getExpressionType</B>()</PRE>
<DL>
<DD>Return a distinguishing name for the expression, for use in diagnostics.
By default the class name is used.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Returns:</B><DD>a distinguishing name for the expression (defaults to the name of the implementation class)</DL>
</DD>
</DL>
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