From f5cf3e3ad0a4865ec75ffb4e58b03557b4d1db2e Mon Sep 17 00:00:00 2001
From: Robert von Burg <eitch@eitchnet.ch>
Date: Mon, 10 Aug 2015 22:20:40 +0200
Subject: [PATCH] [New] Added a DefaultedHashMap for default values on unmapped
 keys

---
 .../utils/collections/DefaultedHashMap.java   | 43 ++++++++++++++++
 .../collections/DefaultedHashMapTest.java     | 51 +++++++++++++++++++
 2 files changed, 94 insertions(+)
 create mode 100644 src/main/java/ch/eitchnet/utils/collections/DefaultedHashMap.java
 create mode 100644 src/test/java/ch/eitchnet/utils/collections/DefaultedHashMapTest.java

diff --git a/src/main/java/ch/eitchnet/utils/collections/DefaultedHashMap.java b/src/main/java/ch/eitchnet/utils/collections/DefaultedHashMap.java
new file mode 100644
index 000000000..10ef2d75b
--- /dev/null
+++ b/src/main/java/ch/eitchnet/utils/collections/DefaultedHashMap.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2015 Robert von Burg <eitch@eitchnet.ch>
+ * 
+ * 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 ch.eitchnet.utils.collections;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author Robert von Burg <eitch@eitchnet.ch>
+ */
+public class DefaultedHashMap<K, V> extends HashMap<K, V> {
+
+	private static final long serialVersionUID = 1L;
+	private V defaultValue;
+
+	/**
+	 * Constructs this {@link Map} instance to have a default value on inexistent keys
+	 * 
+	 * @param defaultValue
+	 *            the default to return if a key is not mapped
+	 */
+	public DefaultedHashMap(V defaultValue) {
+		this.defaultValue = defaultValue;
+	}
+
+	@Override
+	public V get(Object key) {
+		return getOrDefault(key, this.defaultValue);
+	}
+}
diff --git a/src/test/java/ch/eitchnet/utils/collections/DefaultedHashMapTest.java b/src/test/java/ch/eitchnet/utils/collections/DefaultedHashMapTest.java
new file mode 100644
index 000000000..ddf7c6569
--- /dev/null
+++ b/src/test/java/ch/eitchnet/utils/collections/DefaultedHashMapTest.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2015 Robert von Burg <eitch@eitchnet.ch>
+ * 
+ * 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 ch.eitchnet.utils.collections;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Map;
+
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * @author Robert von Burg <eitch@eitchnet.ch>
+ */
+public class DefaultedHashMapTest {
+
+	private Map<String, String> map;
+
+	@Before
+	public void setUp() {
+		this.map = new DefaultedHashMap<String, String>("foobar");
+		this.map.put("foo", "foofoo");
+	}
+
+	@Test
+	public void shouldReturnMappedValue() {
+		assertTrue(this.map.containsKey("foo"));
+		assertEquals("foofoo", this.map.get("foo"));
+	}
+
+	@Test
+	public void shouldReturnDefaultValue() {
+		assertFalse(this.map.containsKey("bar"));
+		assertEquals("foobar", this.map.get("bar"));
+	}
+}