From 8a1588ae295614858089c3382364825aa9f8b7e7 Mon Sep 17 00:00:00 2001
From: Stephane Nicoll <snicoll@pivotal.io>
Date: Fri, 10 Aug 2018 14:28:36 +0200
Subject: [PATCH] Add support for DataSize

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

Issue: SPR-17154
---
 .../springframework/util/unit/DataSize.java   | 248 ++++++++++++++++++
 .../springframework/util/unit/DataUnit.java   |  82 ++++++
 .../util/unit/package-info.java               |  25 ++
 .../util/unit/DataSizeTests.java              | 158 +++++++++++
 4 files changed, 513 insertions(+)
 create mode 100644 spring-core/src/main/java/org/springframework/util/unit/DataSize.java
 create mode 100644 spring-core/src/main/java/org/springframework/util/unit/DataUnit.java
 create mode 100644 spring-core/src/main/java/org/springframework/util/unit/package-info.java
 create mode 100644 spring-core/src/test/java/org/springframework/util/unit/DataSizeTests.java

diff --git a/spring-core/src/main/java/org/springframework/util/unit/DataSize.java b/spring-core/src/main/java/org/springframework/util/unit/DataSize.java
new file mode 100644
index 0000000000..4921de8eba
--- /dev/null
+++ b/spring-core/src/main/java/org/springframework/util/unit/DataSize.java
@@ -0,0 +1,248 @@
+/*
+ * 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 java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * A data size, such as '12MB'.
+ * <p>
+ * This class models a size in terms of bytes and is immutable and thread-safe.
+ *
+ * @author Stephane Nicoll
+ * @since 5.1
+ */
+public class DataSize implements Comparable<DataSize> {
+
+	/**
+	 * The pattern for parsing.
+	 */
+	private static final Pattern PATTERN = Pattern.compile("^(\\d+)([a-zA-Z]{0,2})$");
+
+	/**
+	 * Bytes per KiloByte.
+	 */
+	private static long BYTES_PER_KB = 1024;
+
+	/**
+	 * Bytes per MegaByte.
+	 */
+	private static long BYTES_PER_MB = BYTES_PER_KB * 1024;
+
+	/**
+	 * Bytes per GigaByte.
+	 */
+	private static long BYTES_PER_GB = BYTES_PER_MB * 1024;
+
+	/**
+	 * Bytes per TeraByte.
+	 */
+	private static long BYTES_PER_TB = BYTES_PER_GB * 1024;
+
+
+	private final long bytes;
+
+	private DataSize(long bytes) {
+		this.bytes = bytes;
+	}
+
+
+	/**
+	 * Obtain a {@link DataSize} representing the specified number of bytes.
+	 * @param bytes the number of bytes
+	 * @return a {@link DataSize}
+	 */
+	public static DataSize ofBytes(long bytes) {
+		return new DataSize(bytes);
+	}
+
+	/**
+	 * Obtain a {@link DataSize} representing the specified number of kilobytes.
+	 * @param kiloBytes the number of kilobytes
+	 * @return a {@link DataSize}
+	 */
+	public static DataSize ofKiloBytes(long kiloBytes) {
+		return new DataSize(Math.multiplyExact(kiloBytes, BYTES_PER_KB));
+	}
+
+	/**
+	 * Obtain a {@link DataSize} representing the specified number of megabytes.
+	 * @param megaBytes the number of megabytes
+	 * @return a {@link DataSize}
+	 */
+	public static DataSize ofMegaBytes(long megaBytes) {
+		return new DataSize(Math.multiplyExact(megaBytes, BYTES_PER_MB));
+	}
+
+	/**
+	 * Obtain a {@link DataSize} representing the specified number of gigabytes.
+	 * @param gigaBytes the number of gigabytes
+	 * @return a {@link DataSize}
+	 */
+	public static DataSize ofGigaBytes(long gigaBytes) {
+		return new DataSize(Math.multiplyExact(gigaBytes, BYTES_PER_GB));
+	}
+
+	/**
+	 * Obtain a {@link DataSize} representing the specified number of terabytes.
+	 * @param teraBytes the number of terabytes
+	 * @return a {@link DataSize}
+	 */
+	public static DataSize ofTeraBytes(long teraBytes) {
+		return new DataSize(Math.multiplyExact(teraBytes, BYTES_PER_TB));
+	}
+
+	/**
+	 * Obtain a {@link DataSize} representing an amount in the specified {@link DataUnit}.
+	 * @param amount the amount of the size, measured in terms of the unit
+	 * @return a {@link DataSize}
+	 */
+	public static DataSize of(long amount, DataUnit unit) {
+		Assert.notNull(unit, "Unit must not be null");
+		return new DataSize(Math.multiplyExact(amount, unit.getSize().toBytes()));
+	}
+
+	/**
+	 * Obtain a {@link DataSize} from a text string such as {@code 12MB} using
+	 * {@link DataUnit#BYTES} if no unit is specified.
+	 * <p>
+	 * Examples:
+	 * <pre>
+	 * "12KB" -- parses as "12 kilobytes"
+	 * "5MB"  -- parses as "5 megabytes" (where a minute is 60 seconds)
+	 * "20"   -- parses as "20 bytes"
+	 * </pre>
+	 * @param text the text to parse
+	 * @return the parsed {@link DataSize}
+	 * @see #parse(CharSequence, DataUnit)
+	 */
+	public static DataSize parse(CharSequence text) {
+		return parse(text, null);
+	}
+
+	/**
+	 * Obtain a {@link DataSize} from a text string such as {@code 12MB} using
+	 * the specified default {@link DataUnit} if no unit is specified.
+	 * <p>
+	 * The string starts with a number followed optionally by a unit matching one of the
+	 * supported {@link DataUnit suffixes}.
+	 * <p>
+	 * Examples:
+	 * <pre>
+	 * "12KB" -- parses as "12 kilobytes"
+	 * "5MB"  -- parses as "5 megabytes" (where a minute is 60 seconds)
+	 * "20"   -- parses as "20 kilobytes" (where the {@code defaultUnit} is {@link DataUnit#KILOBYTES})
+	 * </pre>
+	 * @param text the text to parse
+	 * @return the parsed {@link DataSize}
+	 */
+	public static DataSize parse(CharSequence text, @Nullable DataUnit defaultUnit) {
+		Assert.notNull(text, "Text must not be null");
+		try {
+			Matcher matcher = PATTERN.matcher(text);
+			Assert.state(matcher.matches(), "Does not match data size pattern");
+			DataUnit unit = determineDataUnit(matcher.group(2), defaultUnit);
+			Long amount = Long.parseLong(matcher.group(1));
+			return DataSize.of(amount, unit);
+		}
+		catch (Exception ex) {
+			throw new IllegalArgumentException(
+					"'" + text + "' is not a valid data size", ex);
+		}
+	}
+
+	private static DataUnit determineDataUnit(String suffix,
+			@Nullable DataUnit defaultUnit) {
+		defaultUnit = (defaultUnit != null ? defaultUnit : DataUnit.BYTES);
+		return (StringUtils.hasLength(suffix) ? DataUnit.fromSuffix(suffix)
+				: defaultUnit);
+	}
+
+	/**
+	 * Return the number of bytes in this instance.
+	 * @return the number of bytes
+	 */
+	public long toBytes() {
+		return this.bytes;
+	}
+
+	/**
+	 * Return the number of kilobytes in this instance.
+	 * @return the number of kilobytes
+	 */
+	public long toKiloBytes() {
+		return this.bytes / BYTES_PER_KB;
+	}
+
+	/**
+	 * Return the number of megabytes in this instance.
+	 * @return the number of megabytes
+	 */
+	public long toMegaBytes() {
+		return this.bytes / BYTES_PER_MB;
+	}
+
+	/**
+	 * Return the number of gigabytes in this instance.
+	 * @return the number of gigabytes
+	 */
+	public long toGigaBytes() {
+		return this.bytes / BYTES_PER_GB;
+	}
+
+	/**
+	 * Return the number of terabytes in this instance.
+	 * @return the number of terabytes
+	 */
+	public long toTeraBytes() {
+		return this.bytes / BYTES_PER_TB;
+	}
+
+	@Override
+	public int compareTo(DataSize other) {
+		return Long.compare(this.bytes, other.bytes);
+	}
+
+	@Override
+	public String toString() {
+		return String.format("%dB", this.bytes);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) {
+			return true;
+		}
+		if (o == null || getClass() != o.getClass()) {
+			return false;
+		}
+		DataSize that = (DataSize) o;
+		return this.bytes == that.bytes;
+	}
+
+	@Override
+	public int hashCode() {
+		return Long.hashCode(this.bytes);
+	}
+
+}
+
diff --git a/spring-core/src/main/java/org/springframework/util/unit/DataUnit.java b/spring-core/src/main/java/org/springframework/util/unit/DataUnit.java
new file mode 100644
index 0000000000..86158f6ed5
--- /dev/null
+++ b/spring-core/src/main/java/org/springframework/util/unit/DataUnit.java
@@ -0,0 +1,82 @@
+/*
+ * 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 java.util.Objects;
+
+/**
+ * A standard set of data size units.
+ *
+ * @author Stephane Nicoll
+ * @since 5.1
+ */
+public enum DataUnit {
+
+	/**
+	 * Bytes.
+	 */
+	BYTES("B", DataSize.ofBytes(1)),
+
+	/**
+	 * KiloByte.
+	 */
+	KILOBYTES("KB", DataSize.ofKiloBytes(1)),
+
+	/**
+	 * MegaByte.
+	 */
+	MEGABYTES("MB", DataSize.ofMegaBytes(1)),
+
+	/**
+	 * TeraByte.
+	 */
+	GIGABYTES("GB", DataSize.ofGigaBytes(1)),
+
+	/**
+	 * TeraByte.
+	 */
+	TERABYTES("TB", DataSize.ofTeraBytes(1));
+
+	private final String suffix;
+
+	private final DataSize size;
+
+	DataUnit(String suffix, DataSize size) {
+		this.suffix = suffix;
+		this.size = size;
+	}
+
+	protected DataSize getSize() {
+		return this.size;
+	}
+
+	/**
+	 * Return the {@link DataUnit} matching the specified {@code suffix}.
+	 * @param suffix one of the standard suffix
+	 * @return the {@link DataUnit} matching the specified {@code suffix}
+	 * @throws IllegalArgumentException if the suffix does not match any instance
+	 */
+	public static DataUnit fromSuffix(String suffix) {
+		for (DataUnit candidate : values()) {
+			if (Objects.equals(candidate.suffix, suffix)) {
+				return candidate;
+			}
+		}
+		throw new IllegalArgumentException("Unknown unit '" + suffix + "'");
+	}
+
+}
diff --git a/spring-core/src/main/java/org/springframework/util/unit/package-info.java b/spring-core/src/main/java/org/springframework/util/unit/package-info.java
new file mode 100644
index 0000000000..fded112fe5
--- /dev/null
+++ b/spring-core/src/main/java/org/springframework/util/unit/package-info.java
@@ -0,0 +1,25 @@
+/*
+ * 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.
+ */
+
+/**
+ * Useful unit data types.
+ */
+@NonNullApi
+@NonNullFields
+package org.springframework.util.unit;
+
+import org.springframework.lang.NonNullApi;
+import org.springframework.lang.NonNullFields;
\ No newline at end of file
diff --git a/spring-core/src/test/java/org/springframework/util/unit/DataSizeTests.java b/spring-core/src/test/java/org/springframework/util/unit/DataSizeTests.java
new file mode 100644
index 0000000000..091f97ca38
--- /dev/null
+++ b/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");
+	}
+
+}