Generic Recordinality supporting String, Long, or Integer elements

src/main/java/com/cscotta/recordinality/Recordinality.java

@@ -25,7 +25,7 @@
 import com.google.common.hash.HashFunction;
 import com.google.common.collect.ImmutableSet;
 
-public class Recordinality {
+public class Recordinality<T> {
 
     private final int sampleSize;
     private final int seed = new Random().nextInt();
@@ -46,7 +46,7 @@ public Recordinality(int sampleSize) {
     /*
      * Observes a value in a stream.
      */
-    public void observe(String element) {
+    public void observe(T element) {
         boolean inserted = insertIfFits(element);
         if (inserted) modifications.incrementAndGet();
     }
@@ -84,8 +84,17 @@ public Set<Element> getSample() {
     /*
      * Inserts a record into our k-set if it fits.
     */
-    private boolean insertIfFits(String element) {
-        long hashedValue = hash.hashString(element).asLong();
+    private boolean insertIfFits(T element) {
+        long hashedValue = 0L;
+
+        if (element.getClass() == String.class)
+            hashedValue = hash.hashString((String)element).asLong();
+        else if (element.getClass() == Long.class)
+            hashedValue = hash.hashLong((Long)element).asLong();
+        else if (element.getClass() == Integer.class)
+            hashedValue = hash.hashInt((Integer)element).asLong();
+        else
+            throw new ClassCastException();
 
         // Short-circuit if our k-set is saturated. Common case.
         if (hashedValue < cachedMin.get() && kMapSize >= sampleSize)
@@ -141,10 +150,10 @@ public String toString() {
      */
     public class Element {
 
-        public final String value;
+        public final T value;
         public final AtomicLong count;
 
-        public Element(String value) {
+        public Element(T value) {
             this.value = value;
             this.count = new AtomicLong(1);
         }

src/test/java/com/cscotta/recordinality/RecordinalityTest.java

@@ -67,7 +67,7 @@ public Result call() throws Exception {
                     long start = System.currentTimeMillis();
                     final double[] results = new double[numRuns];
                     for (int i = 0; i < numRuns; i++) {
-                        Recordinality rec = new Recordinality(kSize);
+                        Recordinality rec = new Recordinality<String>(kSize);
                         for (String line : lines) rec.observe(line);
                         results[i] = rec.estimateCardinality();
                     }