org.apache.pulsar.common.protocol.schema.BytesSchemaVersion Maven / Gradle / Ivy
/*
* 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.pulsar.common.protocol.schema;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Comparator;
/**
* Bytes schema version.
*/
public class BytesSchemaVersion implements SchemaVersion, Comparable {
private static final char[] HEX_CHARS_UPPER = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
};
private final byte[] bytes;
// cache the hash code for the string, default to 0
private int hashCode;
private BytesSchemaVersion(byte[] bytes) {
this.bytes = bytes;
}
@Override
public byte[] bytes() {
return bytes;
}
public static BytesSchemaVersion of(byte[] bytes) {
return bytes != null ? new BytesSchemaVersion(bytes) : null;
}
/**
* Get the data from the Bytes.
* @return The underlying byte array
*/
public byte[] get() {
return this.bytes;
}
/**
* The hashcode is cached except for the case where it is computed as 0, in which
* case we compute the hashcode on every call.
*
* @return the hashcode
*/
@Override
public int hashCode() {
if (hashCode == 0) {
hashCode = Arrays.hashCode(bytes);
}
return hashCode;
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (other == null) {
return false;
}
// we intentionally use the function to compute hashcode here
if (this.hashCode() != other.hashCode()) {
return false;
}
if (other instanceof BytesSchemaVersion) {
return Arrays.equals(this.bytes, ((BytesSchemaVersion) other).get());
}
return false;
}
@Override
public int compareTo(BytesSchemaVersion that) {
return BYTES_LEXICO_COMPARATOR.compare(this.bytes, that.bytes);
}
@Override
public String toString() {
return BytesSchemaVersion.toString(bytes, 0, bytes.length);
}
/**
* Write a printable representation of a byte array. Non-printable
* characters are hex escaped in the format \\x%02X, eg:
* \x00 \x05 etc.
*
* This function is brought from org.apache.hadoop.hbase.util.Bytes
*
* @param b array to write out
* @param off offset to start at
* @param len length to write
* @return string output
*/
private static String toString(final byte[] b, int off, int len) {
StringBuilder result = new StringBuilder();
if (b == null) {
return result.toString();
}
// just in case we are passed a 'len' that is > buffer length...
if (off >= b.length) {
return result.toString();
}
if (off + len > b.length) {
len = b.length - off;
}
for (int i = off; i < off + len; ++i) {
int ch = b[i] & 0xFF;
if (ch >= ' ' && ch <= '~' && ch != '\\') {
result.append((char) ch);
} else {
result.append("\\x");
result.append(HEX_CHARS_UPPER[ch / 0x10]);
result.append(HEX_CHARS_UPPER[ch % 0x10]);
}
}
return result.toString();
}
/**
* A byte array comparator based on lexicograpic ordering.
*/
public static final ByteArrayComparator BYTES_LEXICO_COMPARATOR = new LexicographicByteArrayComparator();
/**
* This interface helps to compare byte arrays.
*/
public interface ByteArrayComparator extends Comparator, Serializable {
int compare(byte[] buffer1, int offset1, int length1,
byte[] buffer2, int offset2, int length2);
}
private static class LexicographicByteArrayComparator implements ByteArrayComparator {
private static final long serialVersionUID = -1915703761143534937L;
@Override
public int compare(byte[] buffer1, byte[] buffer2) {
return compare(buffer1, 0, buffer1.length, buffer2, 0, buffer2.length);
}
public int compare(final byte[] buffer1, int offset1, int length1,
final byte[] buffer2, int offset2, int length2) {
// short circuit equal case
if (buffer1 == buffer2
&& offset1 == offset2
&& length1 == length2) {
return 0;
}
// similar to Arrays.compare() but considers offset and length
int end1 = offset1 + length1;
int end2 = offset2 + length2;
for (int i = offset1, j = offset2; i < end1 && j < end2; i++, j++) {
int a = buffer1[i] & 0xff;
int b = buffer2[j] & 0xff;
if (a != b) {
return a - b;
}
}
return length1 - length2;
}
}
}