| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.beam.sdk.io.range; |
| |
| import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkNotNull; |
| |
| import com.google.protobuf.ByteString; |
| import com.google.protobuf.ByteString.ByteIterator; |
| import java.io.Serializable; |
| import java.nio.ByteBuffer; |
| import javax.annotation.Nonnull; |
| |
| /** |
| * A class representing a key consisting of an array of bytes. Arbitrary-length {@code byte[]} keys |
| * are typical in key-value stores such as Google Cloud Bigtable. |
| * |
| * <p>Instances of {@link ByteKey} are immutable. |
| * |
| * <p>{@link ByteKey} implements {@link Comparable Comparable<ByteKey>} by comparing the |
| * arrays in lexicographic order. The smallest {@link ByteKey} is a zero-length array; the successor |
| * to a key is the same key with an additional 0 byte appended; and keys have unbounded size. |
| * |
| * <p>Note that the empty {@link ByteKey} compares smaller than all other keys, but some systems |
| * have the semantic that when an empty {@link ByteKey} is used as an upper bound, it represents the |
| * largest possible key. In these cases, implementors should use {@link #isEmpty} to test whether an |
| * upper bound key is empty. |
| */ |
| public final class ByteKey implements Comparable<ByteKey>, Serializable { |
| /** An empty key. */ |
| public static final ByteKey EMPTY = ByteKey.of(); |
| |
| /** |
| * Creates a new {@link ByteKey} backed by a copy of the data remaining in the specified {@link |
| * ByteBuffer}. |
| */ |
| public static ByteKey copyFrom(ByteBuffer value) { |
| return new ByteKey(ByteString.copyFrom(value)); |
| } |
| |
| /** |
| * Creates a new {@link ByteKey} backed by a copy of the specified {@code byte[]}. |
| * |
| * <p>Makes a copy of the underlying array. |
| */ |
| public static ByteKey copyFrom(byte[] bytes) { |
| return new ByteKey(ByteString.copyFrom(bytes)); |
| } |
| |
| /** |
| * Creates a new {@link ByteKey} backed by a copy of the specified {@code int[]}. This method is |
| * primarily used as a convenience to create a {@link ByteKey} in code without casting down to |
| * signed Java {@link Byte bytes}: |
| * |
| * <pre>{@code |
| * ByteKey key = ByteKey.of(0xde, 0xad, 0xbe, 0xef); |
| * }</pre> |
| * |
| * <p>Makes a copy of the input. |
| */ |
| public static ByteKey of(int... bytes) { |
| byte[] ret = new byte[bytes.length]; |
| for (int i = 0; i < bytes.length; ++i) { |
| ret[i] = (byte) (bytes[i] & 0xff); |
| } |
| return ByteKey.copyFrom(ret); |
| } |
| |
| /** Returns a read-only {@link ByteBuffer} representing this {@link ByteKey}. */ |
| public ByteBuffer getValue() { |
| return value.asReadOnlyByteBuffer(); |
| } |
| |
| /** |
| * Returns a newly-allocated {@code byte[]} representing this {@link ByteKey}. |
| * |
| * <p>Copies the underlying {@code byte[]}. |
| */ |
| public byte[] getBytes() { |
| return value.toByteArray(); |
| } |
| |
| /** Returns {@code true} if the {@code byte[]} backing this {@link ByteKey} is of length 0. */ |
| public boolean isEmpty() { |
| return value.isEmpty(); |
| } |
| |
| /** |
| * {@link ByteKey} implements {@link Comparable Comparable<ByteKey>} by comparing the arrays |
| * in lexicographic order. The smallest {@link ByteKey} is a zero-length array; the successor to a |
| * key is the same key with an additional 0 byte appended; and keys have unbounded size. |
| */ |
| @Override |
| public int compareTo(@Nonnull ByteKey other) { |
| checkNotNull(other, "other"); |
| ByteIterator thisIt = value.iterator(); |
| ByteIterator otherIt = other.value.iterator(); |
| while (thisIt.hasNext() && otherIt.hasNext()) { |
| // (byte & 0xff) converts [-128,127] bytes to [0,255] ints. |
| int cmp = (thisIt.nextByte() & 0xff) - (otherIt.nextByte() & 0xff); |
| if (cmp != 0) { |
| return cmp; |
| } |
| } |
| // If we get here, the prefix of both arrays is equal up to the shorter array. The array with |
| // more bytes is larger. |
| return value.size() - other.value.size(); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////////// |
| private final ByteString value; |
| |
| private ByteKey(ByteString value) { |
| this.value = value; |
| } |
| |
| /** Array used as a helper in {@link #toString}. */ |
| private static final char[] HEX = |
| new char[] {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; |
| |
| // Prints the key as a string "[deadbeef]". |
| @Override |
| public String toString() { |
| char[] encoded = new char[2 * value.size() + 2]; |
| encoded[0] = '['; |
| int cnt = 1; |
| ByteIterator iterator = value.iterator(); |
| while (iterator.hasNext()) { |
| byte b = iterator.nextByte(); |
| encoded[cnt] = HEX[(b & 0xF0) >>> 4]; |
| ++cnt; |
| encoded[cnt] = HEX[b & 0xF]; |
| ++cnt; |
| } |
| encoded[cnt] = ']'; |
| return new String(encoded); |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (o == this) { |
| return true; |
| } |
| if (!(o instanceof ByteKey)) { |
| return false; |
| } |
| ByteKey other = (ByteKey) o; |
| return (other.value.size() == value.size()) && this.compareTo(other) == 0; |
| } |
| |
| @Override |
| public int hashCode() { |
| return value.hashCode(); |
| } |
| } |