UTILS-15: typesafe id.

diff --git a/support/general/src/main/java/org/wamblee/general/Id.java b/support/general/src/main/java/org/wamblee/general/Id.java
new file mode 100644 (file)
index 0000000..925732f
--- /dev/null
+++ b/support/general/src/main/java/org/wamblee/general/Id.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2005-2011 the original author or authors.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.wamblee.general;
+
+/**
+ * This class provides a generic typesafe id wrapping a long value.
+ * 
+ * @author Erik Brakkee
+ * 
+ * @param <T>
+ *            Type the id refers to.
+ */
+public class Id<T> implements Comparable<Id<T>> {
+
+    private long id;
+
+    /**
+     * Constructs the id.
+     * 
+     * @param aId
+     *            Integer id.
+     */
+    public Id(long aId) {
+        id = aId;
+    }
+
+    /**
+     * @return The underlying id.
+     */
+    public long getId() {
+        return id;
+    }
+
+    @Override
+    public int hashCode() {
+        return ((Long) id).hashCode();
+    }
+
+    @Override
+    public boolean equals(Object aObj) {
+        if (aObj == null) {
+            return false;
+        }
+        if (!(aObj instanceof Id)) {
+            return false;
+        }
+        return id == ((Id<T>) aObj).id;
+    }
+
+    @Override
+    public String toString() {
+        return id + "";
+    }
+
+    @Override
+    public int compareTo(org.wamblee.general.Id<T> aId) {
+        return ((Long) id).compareTo((Long) aId.getId());
+    }
+}

diff --git a/support/general/src/test/java/org/wamblee/general/IdTest.java b/support/general/src/test/java/org/wamblee/general/IdTest.java
new file mode 100644 (file)
index 0000000..8a442cd
--- /dev/null
+++ b/support/general/src/test/java/org/wamblee/general/IdTest.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2005-2010 the original author or authors.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.wamblee.general;
+
+import static junit.framework.Assert.*;
+
+import org.junit.Test;
+
+public class IdTest {
+
+    @Test
+    public void testGetSet() {
+        Id<IdTest> id = new Id<IdTest>(100L);
+        assertEquals(100L, id.getId());
+    }
+
+    @Test
+    public void testEqualsHashCodeCompare() {
+        Id<IdTest> id1 = new Id<IdTest>(100L);
+        Id<IdTest> id2 = new Id<IdTest>(200L);
+        Id<IdTest> id3 = new Id<IdTest>(100L);
+        assertEquals(id1, id3);
+        assertFalse(id1.equals(id2));
+        assertFalse(id1.equals(null));
+        assertFalse(id1.equals("hello"));
+        assertEquals(id1.hashCode(), id3.hashCode());
+
+        assertTrue(id1.compareTo(id2) < 0);
+        assertTrue(id2.compareTo(id1) > 0);
+        assertEquals(0, id1.compareTo(id3));
+    }
+}