collection_sumfunction.html

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   would return 2.

   The parser might use this information to ensure validity,
   and its also for reporting <Function> capabilities.

  NOTE: this was previously javadoc-ed incorrectly, please note
        the new definition.
  NOTE: you cannot have a function with a variable number of
        arguments.
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../org/geotools/filter/FunctionExpression.html#getArgCount()">getArgCount</A></CODE> in interface <CODE><A HREF="../../../../org/geotools/filter/FunctionExpression.html" title="interface in org.geotools.filter">FunctionExpression</A></CODE><DT><B>Specified by:</B><DD><CODE><A HREF="../../../../org/geotools/filter/FunctionExpressionImpl.html#getArgCount()">getArgCount</A></CODE> in class <CODE><A HREF="../../../../org/geotools/filter/FunctionExpressionImpl.html" title="class in org.geotools.filter">FunctionExpressionImpl</A></CODE></DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>the number of args.</DL>
</DD>
</DL>
<HR>

<A NAME="calculateSum(org.geotools.feature.FeatureCollection, org.geotools.filter.Expression)"><!-- --></A><H3>
calculateSum</H3>
<PRE>
public static <A HREF="../../../../org/geotools/feature/visitor/CalcResult.html" title="interface in org.geotools.feature.visitor">CalcResult</A> <B>calculateSum</B>(<A HREF="../../../../org/geotools/feature/FeatureCollection.html" title="interface in org.geotools.feature">FeatureCollection</A>&nbsp;collection,
                                      <A HREF="../../../../org/geotools/filter/Expression.html" title="interface in org.geotools.filter">Expression</A>&nbsp;expression)
                               throws <A HREF="../../../../org/geotools/filter/IllegalFilterException.html" title="class in org.geotools.filter">IllegalFilterException</A>,
                                      <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></PRE>
<DL>
<DD>Calculate sum (using FeatureCalc) - only one parameter is used.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>collection</CODE> - collection to calculate the sum<DD><CODE>expression</CODE> - Single Expression argument
<DT><B>Returns:</B><DD>An object containing the sum value of the attributes
<DT><B>Throws:</B>
<DD><CODE><A HREF="../../../../org/geotools/filter/IllegalFilterException.html" title="class in org.geotools.filter">IllegalFilterException</A></CODE>
<DD><CODE><A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></CODE></DL>
</DD>
</DL>
<HR>

<A NAME="setArgs(org.geotools.filter.Expression[])"><!-- --></A><H3>
setArgs</H3>
<PRE>
public void <B>setArgs</B>(<A HREF="../../../../org/geotools/filter/Expression.html" title="interface in org.geotools.filter">Expression</A>[]&nbsp;args)</PRE>
<DL>
<DD>The provided arguments are evaulated with respect to the
 FeatureCollection.
 
 <p>
 For an aggregate function (like sum) please use the WFS mandated XPath
 syntax to refer to featureMember content.
 </p>
 
 <p>
 To refer to all 'X': <code>featureMember/asterisk/X</code>
 </p>
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../org/geotools/filter/FunctionExpression.html#setArgs(org.geotools.filter.Expression[])">setArgs</A></CODE> in interface <CODE><A HREF="../../../../org/geotools/filter/FunctionExpression.html" title="interface in org.geotools.filter">FunctionExpression</A></CODE><DT><B>Overrides:</B><DD><CODE><A HREF="../../../../org/geotools/filter/FunctionExpressionImpl.html#setArgs(org.geotools.filter.Expression[])">setArgs</A></CODE> in class <CODE><A HREF="../../../../org/geotools/filter/FunctionExpressionImpl.html" title="class in org.geotools.filter">FunctionExpressionImpl</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>args</CODE> - DOCUMENT ME!
<DT><B>Throws:</B>
<DD><CODE><A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/IllegalArgumentException.html" title="class or interface in java.lang">IllegalArgumentException</A></CODE> - DOCUMENT ME!</DL>
</DD>
</DL>
<HR>

<A NAME="evaluate(org.geotools.feature.Feature)"><!-- --></A><H3>
evaluate</H3>
<PRE>
public <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/Object.html" title="class or interface in java.lang">Object</A> <B>evaluate</B>(<A HREF="../../../../org/geotools/feature/Feature.html" title="interface in org.geotools.feature">Feature</A>&nbsp;feature)</PRE>
<DL>
<DD><B>Description copied from interface: <CODE><A HREF="../../../../org/geotools/filter/Expression.html" title="interface in org.geotools.filter">Expression</A></CODE></B></DD>
<DD>Evaluates the expression against an instance of <A HREF="../../../../org/geotools/feature/Feature.html" title="interface in org.geotools.feature"><CODE>Feature</CODE></A>.
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../org/geotools/filter/Expression.html#evaluate(org.geotools.feature.Feature)">evaluate</A></CODE> in interface <CODE><A HREF="../../../../org/geotools/filter/Expression.html" title="interface in org.geotools.filter">Expression</A></CODE><DT><B>Overrides:</B><DD><CODE><A HREF="../../../../org/geotools/filter/DefaultExpression.html#evaluate(org.geotools.feature.Feature)">evaluate</A></CODE> in class <CODE><A HREF="../../../../org/geotools/filter/DefaultExpression.html" title="class in org.geotools.filter">DefaultExpression</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>feature</CODE> - Specified feature to use when returning value.
<DT><B>Returns:</B><DD>The value of this expression based on the feature.</DL>
</DD>
</DL>
<HR>

<A NAME="setExpression(org.geotools.filter.Expression)"><!-- --></A><H3>
setExpression</H3>
<PRE>
public void <B>setExpression</B>(<A HREF="../../../../org/geotools/filter/Expression.html" title="interface in org.geotools.filter">Expression</A>&nbsp;e)</PRE>
<DL>
<DD><DL>
</DL>
</DD>
<DD><DL>
</DL>
</DD>
</DL>
<HR>

<A NAME="getArgs()"><!-- --></A><H3>
getArgs</H3>
<PRE>
public <A HREF="../../../../org/geotools/filter/Expression.html" title="interface in org.geotools.filter">Expression</A>[] <B>getArgs</B>()</PRE>
<DL>
<DD>Should be an xPath of the form: featureMembers/asterisk/NAME
<P>
<DD><DL>
<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../org/geotools/filter/FunctionExpression.html#getArgs()">getArgs</A></CODE> in interface <CODE><A HREF="../../../../org/geotools/filter/FunctionExpression.html" title="interface in org.geotools.filter">FunctionExpression</A></CODE><DT><B>Overrides:</B><DD><CODE><A HREF="../../../../org/geotools/filter/FunctionExpressionImpl.html#getArgs()">getArgs</A></CODE> in class <CODE><A HREF="../../../../org/geotools/filter/FunctionExpressionImpl.html" title="class in org.geotools.filter">FunctionExpressionImpl</A></CODE></DL>
</DD>
<DD><DL>
</DL>
</DD>
</DL>
<HR>

<A NAME="toString()"><!-- --></A><H3>
toString</H3>
<PRE>
public <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A> <B>toString</B>()</PRE>
<DL>
<DD>Return this function as a string.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>

<DT><B>Returns:</B><DD>String representation of this sum function.</DL>
</DD>
</DL>
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