Initial commit

This adds the initial contents of the repository.

src/main/java/com/github/btrekkie/connectivity/ConnVertex.java

@@ -0,0 +1,41 @@
+package com.github.btrekkie.connectivity;
+
+import java.util.Random;
+
+/** A vertex in a ConnGraph. See the comments for ConnGraph. */
+public class ConnVertex {
+    /**
+     * The thread-local random number generator we use by default to set the "hash" field. We could use
+     * ThreadLocalRandom instead, but ThreadLocalRandom isn't available in Java 6.0 and below.
+     */
+    private static final ThreadLocal<Random> random = new ThreadLocal<Random>() {
+        @Override
+        protected Random initialValue() {
+            return new Random();
+        }
+    };
+
+    /**
+     * A randomly generated integer to use as the return value of hashCode(). ConnGraph relies on random hash codes for
+     * its performance guarantees.
+     */
+    private final int hash;
+
+    public ConnVertex() {
+        hash = random.get().nextInt();
+    }
+
+    /**
+     * Constructs a new ConnVertex.
+     * @param random The random number generator to use to produce a random hash code. ConnGraph relies on random hash
+     *     codes for its performance guarantees.
+     */
+    public ConnVertex(Random random) {
+        hash = random.nextInt();
+    }
+
+    @Override
+    public int hashCode() {
+        return hash;
+    }
+}