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saxon-manual-9.4.0.9-2.mga7.noarch.rpm

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SingleNodeExpression
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net.sf.saxon.expr</FONT>
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Class SingleNodeExpression</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.SingleNodeExpression</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/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="../../../../net/sf/saxon/expr/ParentNodeExpression.html" title="class in net.sf.saxon.expr">ParentNodeExpression</A>, <A HREF="../../../../net/sf/saxon/expr/RootExpression.html" title="class in net.sf.saxon.expr">RootExpression</A></DD>
</DL>
<HR>
<DL>
<DT><PRE>public abstract class <B>SingleNodeExpression</B><DT>extends <A HREF="../../../../net/sf/saxon/expr/Expression.html" title="class in net.sf.saxon.expr">Expression</A></DL>
</PRE>

<P>
A node set expression that will always return zero or one nodes
<P>

<P>
<DL>
<DT><B>See Also:</B><DD><A HREF="../../../../serialized-form.html#net.sf.saxon.expr.SingleNodeExpression">Serialized Form</A></DL>
<HR>

<P>
<!-- =========== FIELD SUMMARY =========== -->

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<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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<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SingleNodeExpression.html#SingleNodeExpression()">SingleNodeExpression</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TD>
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<!-- ========== METHOD SUMMARY =========== -->

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<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SingleNodeExpression.html#computeCardinality()">computeCardinality</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Specify that the expression returns a singleton</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SingleNodeExpression.html#computeSpecialProperties()">computeSpecialProperties</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Compute the special properties of this expression.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;boolean</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SingleNodeExpression.html#effectiveBooleanValue(net.sf.saxon.expr.XPathContext)">effectiveBooleanValue</A></B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the effective boolean value of the expression.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<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/SingleNodeExpression.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>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;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>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SingleNodeExpression.html#getIntrinsicDependencies()">getIntrinsicDependencies</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Determine which aspects of the context the expression depends on.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<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/SingleNodeExpression.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>&nbsp;th)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;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>abstract &nbsp;<A HREF="../../../../net/sf/saxon/om/NodeInfo.html" title="interface in net.sf.saxon.om">NodeInfo</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SingleNodeExpression.html#getNode(net.sf.saxon.expr.XPathContext)">getNode</A></B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the single node to which this expression refers.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;boolean</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../../net/sf/saxon/expr/SingleNodeExpression.html#isContextPossiblyUndefined()">isContextPossiblyUndefined</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Ask whether there is a possibility that the context item will be undefined</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<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/SingleNodeExpression.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>&nbsp;context)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Evaluate the expression in a given context to return an iterator</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>protected abstract &nbsp;<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/SingleNodeExpression.html#noContextMessage()">noContextMessage</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Customize the error message on type checking</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<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/SingleNodeExpression.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>&nbsp;visitor,
         <A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.ContextItemType.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor.ContextItemType</A>&nbsp;contextItemType)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;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>&nbsp;<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/SingleNodeExpression.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>&nbsp;visitor,
          <A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.ContextItemType.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor.ContextItemType</A>&nbsp;contextItemType)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Type-check the expression.</TD>
</TR>
</TABLE>
&nbsp;<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#computeDependencies()">computeDependencies</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#computeStaticProperties()">computeStaticProperties</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#copy()">copy</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#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(net.sf.saxon.trace.ExpressionPresenter)">explain</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#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#iterateSubExpressions()">iterateSubExpressions</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#process(net.sf.saxon.expr.XPathContext)">process</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#promote(net.sf.saxon.expr.parser.PromotionOffer, net.sf.saxon.expr.Expression)">promote</A>, <A HREF="../../../../net/sf/saxon/expr/Expression.html#replaceSubExpression(net.sf.saxon.expr.Expression, net.sf.saxon.expr.Expression)">replaceSubExpression</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#simplify(net.sf.saxon.expr.parser.ExpressionVisitor)">simplify</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>
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<A NAME="SingleNodeExpression()"><!-- --></A><H3>
SingleNodeExpression</H3>
<PRE>
public <B>SingleNodeExpression</B>()</PRE>
<DL>
</DL>

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<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>&nbsp;visitor,
                            <A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.ContextItemType.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor.ContextItemType</A>&nbsp;contextItemType)
                     throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Type-check the expression.
<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="noContextMessage()"><!-- --></A><H3>
noContextMessage</H3>
<PRE>
protected abstract <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>noContextMessage</B>()</PRE>
<DL>
<DD>Customize the error message on type checking
<P>
<DD><DL>
</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>&nbsp;visitor,
                           <A HREF="../../../../net/sf/saxon/expr/parser/ExpressionVisitor.ContextItemType.html" title="class in net.sf.saxon.expr.parser">ExpressionVisitor.ContextItemType</A>&nbsp;contextItemType)
                    throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Perform optimisation of an expression and its subexpressions.
 <p/>
 <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="computeCardinality()"><!-- --></A><H3>
computeCardinality</H3>
<PRE>
public int <B>computeCardinality</B>()</PRE>
<DL>
<DD>Specify that the expression returns a singleton
<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="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>&nbsp;th)</PRE>
<DL>
<DD>Determine the data type of the items returned by this expression
<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>Type.NODE</DL>
</DD>
</DL>
<HR>

<A NAME="getIntrinsicDependencies()"><!-- --></A><H3>
getIntrinsicDependencies</H3>
<PRE>
public int <B>getIntrinsicDependencies</B>()</PRE>
<DL>
<DD>Determine which aspects of the context the expression depends on. The result is
 a bitwise-or'ed value composed from constants such as StaticProperty.VARIABLES and
 StaticProperty.CURRENT_NODE
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#getIntrinsicDependencies()">getIntrinsicDependencies</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>a set of bit-significant flags identifying the "intrinsic"
     dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty</DL>
</DD>
</DL>
<HR>

<A NAME="computeSpecialProperties()"><!-- --></A><H3>
computeSpecialProperties</H3>
<PRE>
public int <B>computeSpecialProperties</B>()</PRE>
<DL>
<DD><B>Description copied from class: <CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#computeSpecialProperties()">Expression</A></CODE></B></DD>
<DD>Compute the special properties of this expression. These properties are denoted by a bit-significant
 integer, possible values are in class <A HREF="../../../../net/sf/saxon/expr/StaticProperty.html" title="class in net.sf.saxon.expr"><CODE>StaticProperty</CODE></A>. The "special" properties are properties
 other than cardinality and dependencies, and most of them relate to properties of node sequences, for
 example whether the nodes are in document order.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#computeSpecialProperties()">computeSpecialProperties</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 special properties, as a bit-significant integer</DL>
</DD>
</DL>
<HR>

<A NAME="getNode(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
getNode</H3>
<PRE>
public abstract <A HREF="../../../../net/sf/saxon/om/NodeInfo.html" title="interface in net.sf.saxon.om">NodeInfo</A> <B>getNode</B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)
                          throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Get the single node to which this expression refers. Returns null if the node-set is empty
<P>
<DD><DL>

<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></CODE></DL>
</DD>
</DL>
<HR>

<A NAME="isContextPossiblyUndefined()"><!-- --></A><H3>
isContextPossiblyUndefined</H3>
<PRE>
public boolean <B>isContextPossiblyUndefined</B>()</PRE>
<DL>
<DD>Ask whether there is a possibility that the context item will be undefined
<P>
<DD><DL>

<DT><B>Returns:</B><DD>true if this is a possibility</DL>
</DD>
</DL>
<HR>

<A NAME="iterate(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
iterate</H3>
<PRE>
public <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>&nbsp;context)
                         throws <A HREF="../../../../net/sf/saxon/trans/XPathException.html" title="class in net.sf.saxon.trans">XPathException</A></PRE>
<DL>
<DD>Evaluate the expression in a given context to return an iterator
<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> - the evaluation context
<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="evaluateItem(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
evaluateItem</H3>
<PRE>
public <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>&nbsp;context)
                  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#evaluateItem(net.sf.saxon.expr.XPathContext)">Expression</A></CODE></B></DD>
<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="effectiveBooleanValue(net.sf.saxon.expr.XPathContext)"><!-- --></A><H3>
effectiveBooleanValue</H3>
<PRE>
public boolean <B>effectiveBooleanValue</B>(<A HREF="../../../../net/sf/saxon/expr/XPathContext.html" title="interface in net.sf.saxon.expr">XPathContext</A>&nbsp;context)
                              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#effectiveBooleanValue(net.sf.saxon.expr.XPathContext)">Expression</A></CODE></B></DD>
<DD>Get the effective boolean value of the expression. This returns false if the value
 is the empty sequence, a zero-length string, a number equal to zero, or the boolean
 false. Otherwise it returns true.
<P>
<DD><DL>
<DT><B>Overrides:</B><DD><CODE><A HREF="../../../../net/sf/saxon/expr/Expression.html#effectiveBooleanValue(net.sf.saxon.expr.XPathContext)">effectiveBooleanValue</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 effective boolean value
<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>
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