Fix for the IPCI issue where ClientsP(p) is greater than P

Author: Kiskae

src/main/java/nl/rug/jbi/jsm/metrics/packagemetrics/IPCI.java

@@ -16,6 +16,7 @@
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static nl.rug.jbi.jsm.metrics.packagemetrics.CollectionAccumulator.DEF_ATOMIC_DOUBLE;
@@ -37,7 +38,11 @@ public IPCI() {
     @Subscribe
     @UsingProducer(PackageProducer.class)
     public void onPackage(final MetricState state, final PackageUnit pack) {
-        state.setValue("IPCI-ClientsP", pack.ClientsP().size());
+        //For this metric, clamp ClientsP to the set P in M. This is done because ClientsP can contain packages
+        //that are not part of the same collection, resulting in a ClientsP that is larger than P, which results
+        //in negative values for this metric.
+        final Set<String> ClientsP = pack.filterSameCollectionP(pack.ClientsP());
+        state.setValue("IPCI-ClientsP", ClientsP.size());
         state.setValue("Collection", pack.getSourceIdentifier());
     }
 

src/main/java/nl/rug/jbi/jsm/metrics/packagemetrics/resource/PackageUnit.java

@@ -1,6 +1,7 @@
 package nl.rug.jbi.jsm.metrics.packagemetrics.resource;
 
 import com.google.common.base.Function;
+import com.google.common.base.Predicate;
 import com.google.common.collect.FluentIterable;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Sets;
@@ -232,4 +233,20 @@ public Iterable<String> apply(ClassData member) {
                 })
                 .toSet();
     }
+
+    /**
+     * Filters the given set of package names so only those that belong to the same collection as this package remain.
+     *
+     * @param packageNames Set of package names to filter
+     * @return A filtered view of the given set.
+     */
+    public Set<String> filterSameCollectionP(final Set<String> packageNames) {
+        return Sets.filter(packageNames, new Predicate<String>() {
+            @Override
+            public boolean apply(final String packageName) {
+                final String otherSource = packagedata.get(packageName).getPackageSource();
+                return data.getPackageSource().equals(otherSource);
+            }
+        });
+    }
 }