Add support for DataSize

This commit provides a data type to represents a size in bytes and other
standard unit.

Issue: SPR-17154

spring-core/src/test/java/org/springframework/util/unit/DataSizeTests.java

@@ -0,0 +1,158 @@
+/*
+ * Copyright 2002-2018 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.util.unit;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import static org.junit.Assert.*;
+
+/**
+ * Tests for {@link DataSize}.
+ *
+ * @author Stephane Nicoll
+ */
+public class DataSizeTests {
+
+	@Rule
+	public final ExpectedException thrown = ExpectedException.none();
+
+	@Test
+	public void ofBytesToBytes() {
+		assertEquals(1024, DataSize.ofBytes(1024).toBytes());
+	}
+
+	@Test
+	public void ofBytesToKiloBytes() {
+		assertEquals(1, DataSize.ofBytes(1024).toKiloBytes());
+	}
+
+	@Test
+	public void ofKiloBytesToKiloBytes() {
+		assertEquals(1024, DataSize.ofKiloBytes(1024).toKiloBytes());
+	}
+
+	@Test
+	public void ofKiloBytesToMegaBytes() {
+		assertEquals(1, DataSize.ofKiloBytes(1024).toMegaBytes());
+	}
+
+	@Test
+	public void ofMegaBytesToMegaBytes() {
+		assertEquals(1024, DataSize.ofMegaBytes(1024).toMegaBytes());
+	}
+
+	@Test
+	public void ofMegaBytesToGigaBytes() {
+		assertEquals(2, DataSize.ofMegaBytes(2048).toGigaBytes());
+	}
+
+	@Test
+	public void ofGigaBytesToGigaBytes() {
+		assertEquals(4096, DataSize.ofGigaBytes(4096).toGigaBytes());
+	}
+
+	@Test
+	public void ofGigaBytesToTeraBytes() {
+		assertEquals(4, DataSize.ofGigaBytes(4096).toTeraBytes());
+	}
+
+	@Test
+	public void ofTeraBytesToGigaBytes() {
+		assertEquals(1024, DataSize.ofTeraBytes(1).toGigaBytes());
+	}
+
+	@Test
+	public void ofWithBytesUnit() {
+		assertEquals(DataSize.ofBytes(10), DataSize.of(10, DataUnit.BYTES));
+	}
+
+	@Test
+	public void ofWithKiloBytesUnit() {
+		assertEquals(DataSize.ofKiloBytes(20), DataSize.of(20, DataUnit.KILOBYTES));
+	}
+
+	@Test
+	public void ofWithMegaBytesUnit() {
+		assertEquals(DataSize.ofMegaBytes(30), DataSize.of(30, DataUnit.MEGABYTES));
+	}
+
+	@Test
+	public void ofWithGigaBytesUnit() {
+		assertEquals(DataSize.ofGigaBytes(40), DataSize.of(40, DataUnit.GIGABYTES));
+	}
+
+	@Test
+	public void ofWithTeraBytesUnit() {
+		assertEquals(DataSize.ofTeraBytes(50), DataSize.of(50, DataUnit.TERABYTES));
+	}
+
+	@Test
+	public void parseWithDefaultUnitUsesBytes() {
+		assertEquals(DataSize.ofKiloBytes(1), DataSize.parse("1024"));
+	}
+
+	@Test
+	public void parseWithNullDefaultUnitUsesBytes() {
+		assertEquals(DataSize.ofKiloBytes(1), DataSize.parse("1024", null));
+	}
+
+	@Test
+	public void parseWithCustomDefaultUnit() {
+		assertEquals(DataSize.ofKiloBytes(1), DataSize.parse("1", DataUnit.KILOBYTES));
+	}
+
+	@Test
+	public void parseWithBytes() {
+		assertEquals(DataSize.ofKiloBytes(1), DataSize.parse("1024B"));
+	}
+
+	@Test
+	public void parseWithKiloBytes() {
+		assertEquals(DataSize.ofBytes(1024), DataSize.parse("1KB"));
+	}
+
+	@Test
+	public void parseWithMegaBytes() {
+		assertEquals(DataSize.ofMegaBytes(4), DataSize.parse("4MB"));
+	}
+
+	@Test
+	public void parseWithGigaBytes() {
+		assertEquals(DataSize.ofMegaBytes(1024), DataSize.parse("1GB"));
+	}
+
+	@Test
+	public void parseWithTeraBytes() {
+		assertEquals(DataSize.ofTeraBytes(1), DataSize.parse("1TB"));
+	}
+
+	@Test
+	public void toStringUsesBytes() {
+		assertEquals("1024B", DataSize.ofKiloBytes(1).toString());
+	}
+
+	@Test
+	public void parseWithUnsupportedUnit() {
+		this.thrown.expect(IllegalArgumentException.class);
+		this.thrown.expectMessage("3WB");
+		this.thrown.expectMessage("is not a valid data size");
+		DataSize.parse("3WB");
+	}
+
+}