Refactor HTTP Range support with ResourceRegion

Prior to this commit, the `ResourceHttpMessageConverter` would support
all HTTP Range requests and `MethodProcessors` would "wrap" controller
handler return values with a `HttpRangeResource` to support that use
case in Controllers.

This commit refactors that support in several ways:
* a new ResourceRegion class has been introduced
* a new, separate, ResourceRegionHttpMessageConverter handles the HTTP
range use cases when serving static resources with the
ResourceHttpRequestHandler
* the support of HTTP range requests on Controller handlers has been
removed until a better solution is found

Issue: SPR-14221, SPR-13834

spring-core/src/test/java/org/springframework/core/io/ResourceRegionTests.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2002-2016 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.springframework.core.io;
+
+import static org.mockito.Mockito.mock;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for the {@link ResourceRegion} class.
+ *
+ * @author Brian Clozel
+ */
+public class ResourceRegionTests {
+
+	@Test(expected = IllegalArgumentException.class)
+	public void shouldThrowExceptionWithNullResource() {
+		new ResourceRegion(null, 0, 1);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void shouldThrowExceptionForNegativePosition() {
+		new ResourceRegion(mock(Resource.class), -1, 1);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void shouldThrowExceptionForNegativeCount() {
+		new ResourceRegion(mock(Resource.class), 0, -1);
+	}
+}

spring-core/src/test/java/org/springframework/util/StreamUtilsTests.java

@@ -21,6 +21,7 @@ import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.charset.Charset;
+import java.util.Arrays;
 import java.util.Random;
 import java.util.UUID;
 
@@ -93,6 +94,15 @@ public class StreamUtilsTests {
 		verify(out, never()).close();
 	}
 
+	@Test
+	public void copyRange() throws Exception {
+		ByteArrayOutputStream out = spy(new ByteArrayOutputStream());
+		StreamUtils.copyRange(new ByteArrayInputStream(bytes), out, 0, 100);
+		byte[] range = Arrays.copyOfRange(bytes, 0, 101);
+		assertThat(out.toByteArray(), equalTo(range));
+		verify(out, never()).close();
+	}
+
 	@Test
 	public void nonClosingInputStream() throws Exception {
 		InputStream source = mock(InputStream.class);