org.apache.qpid.framing.AMQShortString 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.qpid.framing;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.qpid.bytebuffer.QpidByteBuffer;
/**
* 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
{
/**
* The maximum number of octets in AMQ short string as defined in AMQP specification
*/
public static final int MAX_LENGTH = 255;
private static final byte MINUS = (byte)'-';
private static final byte ZERO = (byte) '0';
private static final Logger _logger = LoggerFactory.getLogger(AMQShortString.class);
private final byte[] _data;
private final int _offset;
private int _hashCode;
private String _asString = null;
private final int _length;
private static final char[] EMPTY_CHAR_ARRAY = new char[0];
public static final AMQShortString EMPTY_STRING = new AMQShortString((String)null);
public 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.clone();
_length = data.length;
_offset = 0;
}
public AMQShortString(String string)
{
final byte[] data = EncodingUtils.asUTF8Bytes(string);
final int length = data.length;
if (data.length> MAX_LENGTH)
{
throw new IllegalArgumentException("Cannot create AMQShortString with number of octets over 255!");
}
int hash = 0;
for (int i = 0; i < length; i++)
{
data[i] = (byte) (0xFF & data[i]);
hash = (31 * hash) + data[i];
}
_hashCode = hash;
_data = data;
_length = length;
_offset = 0;
_asString = string == null ? "" : string;
}
public static AMQShortString readAMQShortString(ByteBuffer buffer)
{
int length = ((int) buffer.get()) & 0xff;
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);
return new AMQShortString(data, 0, length);
}
}
public static AMQShortString readAMQShortString(QpidByteBuffer buffer)
{
int length = ((int) buffer.get()) & 0xff;
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);
return new AMQShortString(data, 0, length);
}
}
public AMQShortString(byte[] data, final int offset, final int length)
{
if (length > MAX_LENGTH)
{
throw new IllegalArgumentException("Cannot create AMQShortString with number of octets over 255!");
}
if (data == null)
{
throw new NullPointerException("Cannot create AMQShortString with null data[]");
}
_offset = offset;
_length = length;
_data = data;
}
/**
* Get the length of the short string
* @return length of the underlying byte array
*/
public int length()
{
return _length;
}
public char charAt(int index)
{
return (char) _data[_offset + index];
}
public byte[] getBytes()
{
if(_offset == 0 && _length == _data.length)
{
return _data.clone();
}
else
{
byte[] data = new byte[_length];
System.arraycopy(_data,_offset,data,0,_length);
return data;
}
}
public void writeToBuffer(QpidByteBuffer buffer)
{
final int size = length();
buffer.put((byte)size);
buffer.put(_data, _offset, size);
}
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 = _length;
if(length != otherString._length)
{
return false;
}
final byte[] data = _data;
final byte[] otherData = otherString._data;
final int offset = _offset;
final int otherOffset = otherString._offset;
if(offset == 0 && otherOffset == 0 && length == data.length && length == otherData.length)
{
return Arrays.equals(data, otherData);
}
else
{
int thisIdx = offset;
int otherIdx = otherOffset;
for(int i = length; i-- != 0; )
{
if(!(data[thisIdx++] == otherData[otherIdx++]))
{
return false;
}
}
}
return true;
}
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+_offset];
}
_hashCode = hash;
}
return hash;
}
@Override
public String toString()
{
if (_asString == null)
{
_asString = new String(_data, _offset, _length, StandardCharsets.UTF_8);
}
return _asString;
}
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+_offset];
final byte n = name._data[i+name._offset];
if (d < n)
{
return -1;
}
if (d > n)
{
return 1;
}
}
return (length() == name.length()) ? 0 : -1;
}
}
public int toIntValue()
{
int pos = _offset;
int val = 0;
boolean isNegative = (_data[pos] == MINUS);
if(isNegative)
{
pos++;
}
final int end = _length + _offset;
while(pos < end)
{
int digit = (int) (_data[pos++] - ZERO);
if((digit < 0) || (digit > 9))
{
throw new NumberFormatException("\""+toString()+"\" is not a valid number");
}
val = val * 10;
val += digit;
}
if(isNegative)
{
val = val * -1;
}
return val;
}
public boolean contains(final byte b)
{
final int end = _length + _offset;
for(int i = _offset; 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 new AMQShortString(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 new AMQShortString(obj);
}
}
public static String toString(AMQShortString amqShortString)
{
return amqShortString == null ? null : amqShortString.toString();
}
}