Class ByteChunk

java.lang.Object
org.apache.tomcat.util.buf.AbstractChunk
org.apache.tomcat.util.buf.ByteChunk
All Implemented Interfaces:
Serializable, Cloneable
public final class ByteChunk extends AbstractChunk
This class is used to represent a chunk of bytes, and utilities to manipulate byte[].

The buffer can be modified and used for both input and output.

There are 2 modes: The chunk can be associated with a sink - ByteInputChannel or ByteOutputChannel, which will be used when the buffer is empty (on input) or filled (on output). For output, it can also grow. This operating mode is selected by calling setLimit() or allocate(initial, limit) with limit != -1.

Various search and append method are defined - similar with String and StringBuffer, but operating on bytes.

This is important because it allows processing the http headers directly on the received bytes, without converting to chars and Strings until the strings are needed. In addition, the charset is determined later, from headers or user code.

In a server it is very important to be able to operate on the original byte[] without converting everything to chars. Some protocols are ASCII only, and some allow different non-UNICODE encodings. The encoding is not known beforehand, and can even change during the execution of the protocol. ( for example a multipart message may have parts with different encoding )

For HTTP, it is not very clear how the encoding of RequestURI and mime values can be determined, but it is a great advantage to be able to parse the request without converting to string.

See Also:

  • Field Details

    • DEFAULT_CHARSET

      public static final Charset DEFAULT_CHARSET
      Default encoding used to convert to strings. It should be UTF8, as most standards seem to converge, but the servlet API requires 8859_1, and this object is used mostly for servlets.

  • Constructor Details

    • ByteChunk

      public ByteChunk()
      Creates a new, uninitialized ByteChunk object.

    • ByteChunk

      public ByteChunk(int initial)
      Creates a ByteChunk with the specified initial buffer size.
      Parameters:
      initial - initial buffer size

  • Method Details

    • clone

      public ByteChunk clone() throws CloneNotSupportedException
      Overrides:
      clone in class Object
      Throws:
      CloneNotSupportedException

    • recycle

      public void recycle()
      Description copied from class: AbstractChunk
      Resets the chunk to an uninitialized state.
      Overrides:
      recycle in class AbstractChunk

    • allocate

      public void allocate(int initial, int limit)
      Allocates a buffer with the specified initial size and optional limit.
      Parameters:
      initial - initial size
      limit - maximum size or -1 for unlimited

    • setBytes

      public void setBytes(byte[] b, int off, int len)
      Sets the buffer to the specified sub array of bytes.
      Parameters:
      b - the ascii bytes
      off - the start offset of the bytes
      len - the length of the bytes

    • setCharset

      public void setCharset(Charset charset)
      Sets the character set for this chunk.
      Parameters:
      charset - the character set

    • getCharset

      public Charset getCharset()
      Returns the character set for this chunk.
      Returns:
      the character set

    • getBytes

      public byte[] getBytes()
      Returns the underlying byte array.
      Returns:
      the buffer

    • getBuffer

      public byte[] getBuffer()
      Returns the underlying byte array.
      Returns:
      the buffer

    • setByteInputChannel

      public void setByteInputChannel(ByteChunk.ByteInputChannel in)
      When the buffer is empty, read the data from the input channel.
      Parameters:
      in - The input channel

    • setByteOutputChannel

      public void setByteOutputChannel(ByteChunk.ByteOutputChannel out)
      When the buffer is full, write the data to the output channel. Also used when large amount of data is appended. If not set, the buffer will grow to the limit.
      Parameters:
      out - The output channel

    • append

      public void append(byte b) throws IOException
      Appends a single byte to this chunk.
      Parameters:
      b - the byte to append
      Throws:
      IOException - if writing fails

    • append

      public void append(ByteChunk src) throws IOException
      Appends the contents of another ByteChunk.
      Parameters:
      src - the source chunk
      Throws:
      IOException - if writing fails

    • append

      public void append(byte[] src, int off, int len) throws IOException
      Add data to the buffer.
      Parameters:
      src - Bytes array
      off - Offset
      len - Length
      Throws:
      IOException - Writing overflow data to the output channel failed

    • append

      public void append(ByteBuffer from) throws IOException
      Add data to the buffer.
      Parameters:
      from - the ByteBuffer with the data
      Throws:
      IOException - Writing overflow data to the output channel failed

    • subtract

      public int subtract() throws IOException
      Reads and removes the next byte from this chunk.
      Returns:
      the byte value (0-255) or -1 if end of data
      Throws:
      IOException - if reading from input channel fails

    • subtractB

      @Deprecated public byte subtractB() throws IOException
      Deprecated.
      Use subtract() instead. This method cannot distinguish between EOF (-1) and the legitimate byte value 0xFF because it returns byte.
      Reads and removes the next byte from this chunk.
      Returns:
      the byte value or -1 if end of data
      Throws:
      IOException - if reading from input channel fails

    • subtract

      public int subtract(byte[] dest, int off, int len) throws IOException
      Reads bytes into the specified array.
      Parameters:
      dest - destination array
      off - offset
      len - maximum length
      Returns:
      number of bytes read or -1 if end of data
      Throws:
      IOException - if reading from input channel fails

    • subtract

      public int subtract(ByteBuffer to) throws IOException
      Transfers bytes from the buffer to the specified ByteBuffer. After the operation the position of the ByteBuffer will be returned to the one before the operation, the limit will be the position incremented by the number of the transferred bytes.
      Parameters:
      to - the ByteBuffer into which bytes are to be written.
      Returns:
      an integer specifying the actual number of bytes read, or -1 if the end of the stream is reached
      Throws:
      IOException - if an input or output exception has occurred

    • flushBuffer

      public void flushBuffer() throws IOException
      Send the buffer to the sink. Called by append() when the limit is reached. You can also call it explicitly to force the data to be written.
      Throws:
      IOException - Writing overflow data to the output channel failed

    • makeSpace

      public void makeSpace(int count)
      Make space for len bytes. If len is small, allocate a reserve space too. Never grow bigger than the limit or AbstractChunk.ARRAY_MAX_SIZE.
      Parameters:
      count - The size

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • toString

      public String toString(CodingErrorAction malformedInputAction, CodingErrorAction unmappableCharacterAction) throws CharacterCodingException
      Converts the byte chunk to a String using the configured charset.
      Parameters:
      malformedInputAction - action for malformed input
      unmappableCharacterAction - action for unmappable characters
      Returns:
      the string representation
      Throws:
      CharacterCodingException - if conversion fails

    • toStringInternal

      public String toStringInternal(CodingErrorAction malformedInputAction, CodingErrorAction unmappableCharacterAction) throws CharacterCodingException
      Converts the current content of the byte buffer to a String using the configured character set.
      Parameters:
      malformedInputAction - Action to take if the input is malformed
      unmappableCharacterAction - Action to take if a byte sequence can't be mapped to a character
      Returns:
      The result of converting the bytes to a String
      Throws:
      CharacterCodingException - If an error occurs during the conversion

    • getLong

      public long getLong()
      Parses the byte chunk content as a long integer.
      Returns:
      the parsed long value

    • equals

      public boolean equals(Object obj)
      Description copied from class: AbstractChunk

      Sub-classes must provide an equals implementation that is consistent with AbstractChunk.hashCode().

      Specified by:
      equals in class AbstractChunk

    • equals

      public boolean equals(String s)
      Compares the message bytes to the specified String object.

      NOTE: This only works for characters in the range 0-127.

      Parameters:
      s - the String to compare
      Returns:
      true if the comparison succeeded, false otherwise

    • equalsIgnoreCase

      public boolean equalsIgnoreCase(String s)
      Compares the message bytes to the specified String object.

      NOTE: This only works for characters in the range 0-255.

      Parameters:
      s - the String to compare
      Returns:
      true if the comparison succeeded, false otherwise

    • equals

      public boolean equals(ByteChunk bb)
      Compares this chunk to another ByteChunk.
      Parameters:
      bb - the ByteChunk to compare
      Returns:
      true if equal

    • equals

      public boolean equals(byte[] b2, int off2, int len2)
      Compares this chunk to a byte array region.
      Parameters:
      b2 - the byte array
      off2 - offset
      len2 - length
      Returns:
      true if equal

    • equalsIgnoreCase

      public boolean equalsIgnoreCase(byte[] b2, int off2, int len2)
      Compares this chunk to a byte array region, ignoring case.
      Parameters:
      b2 - the byte array
      off2 - offset
      len2 - length
      Returns:
      true if equal

    • equals

      public boolean equals(CharChunk cc)
      Compares this chunk to a CharChunk.
      Parameters:
      cc - the CharChunk to compare
      Returns:
      true if equal

    • equals

      public boolean equals(char[] c2, int off2, int len2)
      Compares the message bytes to the specified char array.

      NOTE: This only works for characters in the range 0-127.

      Parameters:
      c2 - the array to compare to
      off2 - offset
      len2 - length
      Returns:
      true if the comparison succeeded, false otherwise

    • startsWith

      public boolean startsWith(String s, int pos)
      Returns true if the buffer starts with the specified string when tested in a case-sensitive manner.

      NOTE: This only works for characters in the range 0-127.

      Parameters:
      s - the string
      pos - The position
      Returns:
      true if the start matches

    • startsWithIgnoreCase

      public boolean startsWithIgnoreCase(String s, int pos)
      Returns true if the buffer starts with the specified string when tested in a case-insensitive manner.

      NOTE: This only works for characters in the range 0-255.

      Parameters:
      s - the string
      pos - The position
      Returns:
      true if the start matches

    • getBufferElement

      protected int getBufferElement(int index)
      Description copied from class: AbstractChunk
      Returns the element at the specified index in the buffer.
      Specified by:
      getBufferElement in class AbstractChunk
      Parameters:
      index - the element location in the buffer
      Returns:
      the element

    • indexOf

      public int indexOf(char c, int starting)
      Returns the first instance of the given character in this ByteChunk starting at the specified byte. If the character is not found, -1 is returned.

      NOTE: This only works for characters in the range 0-127.

      Parameters:
      c - The character
      starting - The start position
      Returns:
      The position of the first instance of the character or -1 if the character is not found.

    • indexOf

      public static int indexOf(byte[] bytes, int start, int end, char s)
      Returns the first instance of the given character in the given byte array between the specified start and end.

      NOTE: This only works for characters in the range 0-127.

      Parameters:
      bytes - The array to search
      start - The point to start searching from in the array
      end - The point to stop searching in the array
      s - The character to search for
      Returns:
      The position of the first instance of the character or -1 if the character is not found.

    • findByte

      public static int findByte(byte[] bytes, int start, int end, byte b)
      Returns the first instance of the given byte in the byte array between the specified start and end.
      Parameters:
      bytes - The byte array to search
      start - The point to start searching from in the byte array
      end - The point to stop searching in the byte array
      b - The byte to search for
      Returns:
      The position of the first instance of the byte or -1 if the byte is not found.

    • findBytes

      public static int findBytes(byte[] bytes, int start, int end, byte[] b)
      Returns the first instance of the given bytes in the byte array between the specified start and end.
      Parameters:
      bytes - The byte array to search
      start - The point to start searching from in the byte array
      end - The point to stop searching in the byte array
      b - The array of bytes to search for
      Returns:
      The position of the first instance of the byte or -1 if the byte is not found.

    • convertToBytes

      public static byte[] convertToBytes(String value)
      Convert specified String to a byte array. This ONLY WORKS for ascii, UTF chars will be truncated.
      Parameters:
      value - to convert to byte array
      Returns:
      the byte array value