DATAMONGO-1404 - Add support for $min and $max update operators.

Original pull request: #353.
CLA: 169820160330091912 (Alexey Plotnik)

Author: odiszapc

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Update.java

@@ -312,6 +312,34 @@ public Update multiply(String key, Number multiplier) {
 		addMultiFieldOperation("$mul", key, multiplier.doubleValue());
 		return this;
 	}
+	
+	/**
+	 * Update using the {@literal $max} update modifier
+	 *
+	 * @see http://docs.mongodb.org/manual/reference/operator/update/max/
+	 * @param key
+	 * @param value
+	 * @return
+	 */
+	public Update max(String key, Object value) {
+		Assert.notNull(value, "Value must not be 'null'.");
+		addMultiFieldOperation("$max", key, value);
+		return this;
+	}
+
+	/**
+	 * Update using the {@literal $max} update modifier
+	 *
+	 * @see http://docs.mongodb.org/manual/reference/operator/update/min/
+	 * @param key
+	 * @param value
+	 * @return
+	 */
+	public Update min(String key, Object value) {
+		Assert.notNull(value, "Value must not be 'null'.");
+		addMultiFieldOperation("$min", key, value);
+		return this;
+	}
 
 	/**
 	 * The operator supports bitwise {@code and}, bitwise {@code or}, and bitwise {@code xor} operations.

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/query/UpdateTests.java

@@ -490,4 +490,94 @@ public void registersMultiplePullAllClauses() {
 		assertThat(pullAll.get("field1"), is(notNullValue()));
 		assertThat(pullAll.get("field2"), is(notNullValue()));
 	}
+
+	/**
+	 * @see DATAMONGO-1404
+	 */
+	@Test(expected = IllegalArgumentException.class)
+	public void maxShouldThrowExceptionForNullMultiplier() {
+		new Update().max("key", null);
+	}
+
+	/**
+	 * @see DATAMONGO-1404
+	 */
+	@Test(expected = IllegalArgumentException.class)
+	public void minShouldThrowExceptionForNullMultiplier() {
+		new Update().min("key", null);
+	}
+
+	/**
+	 * @see DATAMONGO-1404
+	 */
+	@Test
+	public void getUpdateObjectShouldReturnCorrectRepresentationForMax() {
+
+		Update update = new Update().max("key", 10);
+
+		assertThat(update.getUpdateObject(), equalTo(new Document().append("$max", new Document("key", 10))));
+	}
+
+	/**
+	 * @see DATAMONGO-1404
+	 */
+	@Test
+	public void getUpdateObjectShouldReturnCorrectRepresentationForMin() {
+
+		Update update = new Update().min("key", 10);
+
+		assertThat(update.getUpdateObject(), equalTo(new Document().append("$min", new Document("key", 10))));
+	}
+
+	/**
+	 * @see DATAMONGO-1404
+	 */
+	@Test
+	public void shouldSuppressPreviousValueForMax() {
+
+		Update update = new Update().max("key", 10);
+
+		update.max("key", 99);
+
+		assertThat(update.getUpdateObject(), equalTo(new Document().append("$max", new Document("key", 99))));
+	}
+
+	/**
+	 * @see DATAMONGO-1404
+	 */
+	@Test
+	public void shouldSuppressPreviousValueForMin() {
+
+		Update update = new Update().min("key", 10);
+
+		update.max("key", 99);
+
+		assertThat(update.getUpdateObject(), equalTo(new Document().append("$min9", new Document("key", 99))));
+	}
+
+	/**
+	 * @see DATAMONGO-1404
+	 */
+	@Test
+	public void getUpdateObjectShouldReturnCorrectDateRepresentationForMax() {
+
+		final java.util.Date date = new java.util.Date();
+
+		Update update = new Update().max("key", date);
+
+		assertThat(update.getUpdateObject(), equalTo(new Document().append("$max", new Document("key", date))));
+	}
+
+	/**
+	 * @see DATAMONGO-1404
+	 */
+	@Test
+	public void getUpdateObjectShouldReturnCorrectDateRepresentationForMin() {
+
+		final java.util.Date date = new java.util.Date();
+
+		Update update = new Update().min("key", date);
+
+		assertThat(update.getUpdateObject(), equalTo(new Document().append("$min", new Document("key", date))));
+	}
 }