Package org.apache.derby.impl.drda

Class DRDAString

  • final class DRDAString
extends java.lang.Object
    This class provides functionality for reusing buffers and strings when parsing DRDA packets. A byte array representing a string is stored internally. When the string is requested as a String object, the byte array is converted to a string, and the string is cached to avoid unnecessary conversion later.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private byte[] buffer
      Buffer representing the string.
      private java.lang.String cachedString
      The previously generated string.
      private boolean modified
      True if the contents were modified in the previous call to setBytes.
      private DDMWriter writer
      Keep the DDMWriter as it contains the current CCSID manager being used

    • Constructor Summary

      Constructors 
      Constructor Description
      DRDAString​(DDMWriter w)
      Create a new DRDAString instance.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      private boolean equalTo​(byte[] buf, int offset, int size)
      Check whether the internal buffer contains the same data as another byte buffer.
      byte[] getBytes()
      Return the internal byte array.
      int length()
      Return the length in bytes of the internal string representation.
      void setBytes​(byte[] src, int offset, int size)
      Modify the internal byte buffer.
      java.lang.String toString()
      Convert the internal byte array to a string.
      boolean wasModified()
      Check whether the contents of the DRDAString were modified in the previous call to setBytes().

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

    • Field Detail

      • buffer

        private byte[] buffer
        Buffer representing the string.

      • writer

        private final DDMWriter writer
        Keep the DDMWriter as it contains the current CCSID manager being used

      • modified

        private boolean modified
        True if the contents were modified in the previous call to setBytes.

      • cachedString

        private java.lang.String cachedString
        The previously generated string.

    • Constructor Detail

      • DRDAString

        DRDAString​(DDMWriter w)
        Create a new DRDAString instance.
        Parameters:
        w - a DDMWriter which holds current CCSidManager and which encoding is used

    • Method Detail

      • equalTo

        private boolean equalTo​(byte[] buf,
                        int offset,
                        int size)
        Check whether the internal buffer contains the same data as another byte buffer.
        Parameters:
        buf - a byte array
        offset - start position in the byte array
        size - how many bytes to read from the byte array
        Returns:
        true if the internal buffer contains the same data as the specified byte array

      • setBytes

        public void setBytes​(byte[] src,
                     int offset,
                     int size)
        Modify the internal byte buffer. If the new data is equal to the old data, the cached values are not cleared.
        Parameters:
        src - the new bytes
        offset - start offset
        size - number of bytes to use

      • wasModified

        public boolean wasModified()
        Check whether the contents of the DRDAString were modified in the previous call to setBytes().
        Returns:
        true if the contents were modified

      • toString

        public java.lang.String toString()
        Convert the internal byte array to a string. The string value is cached.
        Overrides:
        toString in class java.lang.Object
        Returns:
        a String value

      • length

        public int length()
        Return the length in bytes of the internal string representation.
        Returns:
        length of internal representation

      • getBytes

        public byte[] getBytes()
        Return the internal byte array. The returned array should not be modified, as it is used internally in DRDAString. The value of the array might be modified by subsequent calls to DRDAString.setBytes().
        Returns:
        internal buffer