| /* |
| * |
| * 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.qpid.server.protocol.v0_8; |
| |
| import java.nio.ByteBuffer; |
| import java.nio.charset.StandardCharsets; |
| import java.util.Arrays; |
| |
| import com.google.common.cache.Cache; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.qpid.server.bytebuffer.QpidByteBuffer; |
| import org.apache.qpid.server.virtualhost.CacheFactory; |
| import org.apache.qpid.server.virtualhost.NullCache; |
| |
| /** |
| * A short string is a representation of an AMQ Short String |
| * Short strings differ from the Java String class by being limited to on ASCII characters (0-127) |
| * and thus can be held more effectively in a byte buffer. |
| * |
| */ |
| public final class AMQShortString implements Comparable<AMQShortString> |
| { |
| /** |
| * The maximum number of octets in AMQ short string as defined in AMQP specification |
| */ |
| public static final int MAX_LENGTH = 255; |
| |
| private static final Logger LOGGER = LoggerFactory.getLogger(AMQShortString.class); |
| private static final NullCache<ByteBuffer, AMQShortString> NULL_CACHE = new NullCache<>(); |
| |
| // Unfortunately CacheBuilder does not yet support keyEquivalence, so we have to wrap the keys in ByteBuffers |
| // rather than using the byte arrays as keys. |
| private static final ThreadLocal<Cache<ByteBuffer, AMQShortString>> CACHE = |
| ThreadLocal.withInitial(() -> CacheFactory.getCache("amqShortStringCache", NULL_CACHE)); |
| |
| private final byte[] _data; |
| private int _hashCode; |
| private String _asString = null; |
| |
| public static final AMQShortString EMPTY_STRING = createAMQShortString((String)null); |
| |
| |
| private AMQShortString(byte[] data) |
| { |
| if (data == null) |
| { |
| throw new NullPointerException("Cannot create AMQShortString with null data[]"); |
| } |
| if (data.length > MAX_LENGTH) |
| { |
| throw new IllegalArgumentException("Cannot create AMQShortString with number of octets over 255!"); |
| } |
| _data = data; |
| } |
| |
| private static byte[] readAMQShortStringAsBytes(QpidByteBuffer buffer) |
| { |
| int length = buffer.getUnsignedByte(); |
| if(length == 0) |
| { |
| return null; |
| } |
| else |
| { |
| if (length > MAX_LENGTH) |
| { |
| throw new IllegalArgumentException("Cannot create AMQShortString with number of octets over 255!"); |
| } |
| if(length > buffer.remaining()) |
| { |
| throw new IllegalArgumentException("Cannot create AMQShortString with length " |
| + length + " from a ByteBuffer with only " |
| + buffer.remaining() |
| + " bytes."); |
| |
| } |
| byte[] data = new byte[length]; |
| buffer.get(data,0, length); |
| |
| return data; |
| } |
| } |
| |
| public static String readAMQShortStringAsString(QpidByteBuffer buffer) |
| { |
| byte[] data = readAMQShortStringAsBytes(buffer); |
| if (data == null) |
| { |
| return null; |
| } |
| else |
| { |
| return new String(data, StandardCharsets.UTF_8); |
| } |
| } |
| |
| public static AMQShortString readAMQShortString(QpidByteBuffer buffer) |
| { |
| byte[] data = readAMQShortStringAsBytes(buffer); |
| if (data == null) |
| { |
| return null; |
| } |
| else |
| { |
| ByteBuffer stringBuffer = ByteBuffer.wrap(data); |
| AMQShortString cached = getShortStringCache().getIfPresent(stringBuffer); |
| if (cached == null) |
| { |
| cached = new AMQShortString(data); |
| getShortStringCache().put(stringBuffer, cached); |
| } |
| return cached; |
| } |
| } |
| |
| public static AMQShortString createAMQShortString(byte[] data) |
| { |
| if (data == null) |
| { |
| throw new NullPointerException("Cannot create AMQShortString with null data[]"); |
| } |
| |
| final AMQShortString cached = getShortStringCache().getIfPresent(ByteBuffer.wrap(data)); |
| return cached != null ? cached : new AMQShortString(data); |
| } |
| |
| public static AMQShortString createAMQShortString(String string) |
| { |
| final byte[] data = EncodingUtils.asUTF8Bytes(string); |
| |
| final AMQShortString cached = getShortStringCache().getIfPresent(ByteBuffer.wrap(data)); |
| if (cached != null) |
| { |
| return cached; |
| } |
| else |
| { |
| final AMQShortString shortString = new AMQShortString(data); |
| |
| int hash = 0; |
| for (int i = 0; i < data.length; i++) |
| { |
| data[i] = (byte) (0xFF & data[i]); |
| hash = (31 * hash) + data[i]; |
| } |
| shortString._hashCode = hash; |
| shortString._asString = string; |
| return shortString; |
| } |
| } |
| |
| /** |
| * Get the length of the short string |
| * @return length of the underlying byte array |
| */ |
| public int length() |
| { |
| return _data.length; |
| } |
| |
| public char charAt(int index) |
| { |
| return (char) _data[index]; |
| |
| } |
| |
| public byte[] getBytes() |
| { |
| return _data.clone(); |
| } |
| |
| public void writeToBuffer(QpidByteBuffer buffer) |
| { |
| writeShortStringBytes(buffer, _data); |
| } |
| |
| public static void writeShortString(final QpidByteBuffer buffer, final String data) |
| { |
| writeShortStringBytes(buffer, data.getBytes(StandardCharsets.UTF_8)); |
| } |
| |
| private static void writeShortStringBytes(final QpidByteBuffer buffer, final byte[] data) |
| { |
| final short size = (short) data.length; |
| buffer.putUnsignedByte(size); |
| buffer.put(data, 0, size); |
| } |
| |
| @Override |
| public boolean equals(Object o) |
| { |
| |
| if (o == this) |
| { |
| return true; |
| } |
| |
| if(o instanceof AMQShortString) |
| { |
| return equals((AMQShortString) o); |
| } |
| |
| return false; |
| |
| } |
| |
| public boolean equals(final AMQShortString otherString) |
| { |
| if (otherString == this) |
| { |
| return true; |
| } |
| |
| if (otherString == null) |
| { |
| return false; |
| } |
| |
| final int hashCode = _hashCode; |
| |
| final int otherHashCode = otherString._hashCode; |
| |
| if ((hashCode != 0) && (otherHashCode != 0) && (hashCode != otherHashCode)) |
| { |
| return false; |
| } |
| |
| final int length = _data.length; |
| |
| if(length != otherString._data.length) |
| { |
| return false; |
| } |
| |
| return Arrays.equals(_data, otherString._data); |
| |
| } |
| |
| @Override |
| public int hashCode() |
| { |
| int hash = _hashCode; |
| if (hash == 0) |
| { |
| final int size = length(); |
| |
| for (int i = 0; i < size; i++) |
| { |
| hash = (31 * hash) + _data[i]; |
| } |
| |
| _hashCode = hash; |
| } |
| |
| return hash; |
| } |
| |
| @Override |
| public String toString() |
| { |
| if (_asString == null) |
| { |
| _asString = new String(_data, StandardCharsets.UTF_8); |
| } |
| return _asString; |
| } |
| |
| @Override |
| public int compareTo(AMQShortString name) |
| { |
| if(name == this) |
| { |
| return 0; |
| } |
| else if (name == null) |
| { |
| return 1; |
| } |
| else |
| { |
| |
| if (name.length() < length()) |
| { |
| return -name.compareTo(this); |
| } |
| |
| for (int i = 0; i < length(); i++) |
| { |
| final byte d = _data[i]; |
| final byte n = name._data[i]; |
| if (d < n) |
| { |
| return -1; |
| } |
| |
| if (d > n) |
| { |
| return 1; |
| } |
| } |
| |
| return (length() == name.length()) ? 0 : -1; |
| } |
| } |
| |
| public boolean contains(final byte b) |
| { |
| final int end = _data.length; |
| for(int i = 0; i < end; i++) |
| { |
| if(_data[i] == b) |
| { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| public static AMQShortString validValueOf(Object obj) |
| { |
| return valueOf(obj,true,true); |
| } |
| |
| static AMQShortString valueOf(Object obj, boolean truncate, boolean nullAsEmptyString) |
| { |
| if (obj == null) |
| { |
| if (nullAsEmptyString) |
| { |
| return EMPTY_STRING; |
| } |
| return null; |
| } |
| else |
| { |
| String value = String.valueOf(obj); |
| int strLength = Math.min(value.length(), AMQShortString.MAX_LENGTH); |
| |
| byte[] bytes = EncodingUtils.asUTF8Bytes(value); |
| if(truncate) |
| { |
| while (bytes.length > AMQShortString.MAX_LENGTH) |
| { |
| value = value.substring(0, strLength-- - 3) + "..."; |
| bytes = EncodingUtils.asUTF8Bytes(value); |
| } |
| |
| } |
| return createAMQShortString(bytes); |
| } |
| } |
| |
| public static AMQShortString valueOf(Object obj) |
| { |
| return valueOf(obj, false, false); |
| } |
| |
| public static AMQShortString valueOf(String obj) |
| { |
| if(obj == null) |
| { |
| return null; |
| } |
| else |
| { |
| return createAMQShortString(obj); |
| } |
| |
| } |
| |
| public static String toString(AMQShortString amqShortString) |
| { |
| return amqShortString == null ? null : amqShortString.toString(); |
| } |
| |
| static Cache<ByteBuffer, AMQShortString> getShortStringCache() |
| { |
| return CACHE.get(); |
| } |
| |
| /** Unit testing only */ |
| static void setShortStringCache(final Cache<ByteBuffer, AMQShortString> cache) |
| { |
| CACHE.set(cache); |
| } |
| } |