add containsFeature() method

app/carnival-util/src/main/groovy/carnival/util/FeatureReport.groovy

@@ -1224,6 +1224,32 @@ class FeatureReport extends MappedDataTable {
     }
 
 
+    /**
+     * Check if a feature with the given name already exists for the given 
+     * subjectId.
+     *
+     * @param subjectId The subject identifier.
+     * @param featureName The feature name.
+     * @return True if the subject has a feature of the given name, false 
+     * otherwise.
+     * 
+     */
+    public boolean containsFeature(String subjectId, String featureName) {
+        assert subjectId != null : "subjectId cannot be null. featureName:${featureName} featureValue:${featureValue}"
+        assert featureName != null : "featureName cannot be null. subjectId:${subjectId} featureValue:${featureValue}"
+
+        // check if feature already exists
+        def fv = this.dataGet(subjectId)
+        if (fv == null) throw new RuntimeException("no feature vector for ${subjectId}")
+
+        def ffn = this.toFieldName(featureName)
+
+        return fv.containsKey(ffn)
+    }
+
+
+
+
     /** 
      * Add a feature to the subject identified by subjectId.
      *

app/carnival-util/src/test/groovy/carnival/util/FeatureReportSpec.groovy

@@ -717,6 +717,24 @@ class FeatureReportSpec extends Specification {
     }
 
 
+    def "contains feature"() {
+        given:
+        Exception e
+        def frp = new FeatureReport(name:'frp-test', idFieldName:'ID')
+        frp.dataModes([FeatureReport.DataMode.ADD_SUBJECT, FeatureReport.DataMode.ADD_FEATURE])
+        frp.addSubject('id1')
+
+        when:
+        frp.addFeature('id1', 'v1', 'v11')
+        boolean b1 = frp.containsFeature('id1', 'v1')
+        boolean b2 = frp.containsFeature('id1', 'v2')
+
+        then:
+        b1
+        !b2
+    }
+
+
     def "add feature"() {
         given:
         Exception e