Illegal value at 'filematch': patternSet{ includes: [Index_*.xml] excludes: [] } - ant

Question

I have to search a given string "OK" from a file Index_*.xml. This * is a random generated Id. This file is generated after every 15seconds
This is what I have done so far, but I am getting the exception " Illegal value at 'filematch': patternSet{ includes: [Index_*.xml] excludes: [] }"
<?xml version="1.0" encoding="UTF-8"?>
<project name="StringSearch" default="wait-for-some-time" basedir=".">
<patternset id="filematch">
<include name="Index_*.xml"/>
</patternset>
<target name="wait-for-some-time">
<waitfor maxwait="15" maxwaitunit="second" timeoutproperty="notfound">
<resourcecontains refid="filematch" substring="OK" />
</waitfor>
<antcall target="success" />
</target>
<target name="success" depends="fail" unless="notfound">
<echo message="String OK found" />
</target>
<target name="fail" if="notfound">
<echo message="String not found" />
</target>
</project>
Any suggestion of what is wrong here or may be another approach if this is not feasible.
Thanks
New code:
Using this
<path id="pathtoIndexfile">
<fileset dir="${destination.dir}">
<include name="Index_*.xml"/>
</fileset>
</path>
<target name="wait-for-some-time">
<echo>${destination.dir}</echo>
<waitfor maxwait="1" maxwaitunit="minute" timeoutproperty="notfound">
<resourcecontains refid="pathtoIndexfile" substring="OK" />
</waitfor>
<antcall target="success" />
</target>
1) The exception is "java.lang.ClassCastException: org.apache.tools.ant.types.Path cannot be cast to org.apache.tools.ant.types.Resource".
2) With fileSet the exception is "java.lang.ClassCastException: org.apache.tools.ant.types.FileSet cannot be cast to org.apache.tools.ant.types.Resource"
Am I missing some Jars?

Answer 1

I have achieved the solution by two steps which are as follows:
Step 1: Copying the index_*.xml file to output.xml file
Step 2: Search OK in the output.xml file
My improvised code which does the search of a string "OK" is
<target name="StringSearch">
<sleep seconds="10"/>
<copy tofile="${destination.dir}/output.xml">
<fileset dir="${destination.dir}">
<include name="Index_*.xml"/>
</fileset>
</copy>
<sleep seconds="10"/>
<echo>destination.dir is: ${destination.dir}</echo>
<loadfile property="OK.exists" srcfile="${destination.dir}/output.xml">
<filterchain>
<linecontainsregexp>
<regexp pattern="OK"/>
</linecontainsregexp>
</filterchain>
</loadfile>
<echo>OK exists: ${OK.exists}</echo>
</target>