Class jdbcBlob

  • All Implemented Interfaces:
    java.sql.Blob

    public class jdbcBlob
    extends java.lang.Object
    implements java.sql.Blob
    The representation (mapping) in the JavaTM programming language of an SQL BLOB value.

    Provides methods for getting the length of an SQL BLOB (Binary Large Object) value, for materializing a BLOB value on the client, and for determining the position of an octet sequence (byte pattern) within a BLOB value.

    HSQLDB-Specific Information:

    Including 1.8.x, the HSQLDB driver does not implement Blob using an SQL locator(BLOB). That is, an HSQLDB Blob object does not contain a logical pointer to SQL BLOB data; rather it directly contains a representation of the data (a byte array). As a result, an HSQLDB Blob object is itself valid beyond the duration of the transaction in which is was created, although it does not necessarily represent a corresponding value on the database.

    Currently, the interface methods for updating a BLOB value are unsupported. However, the truncate method is supported for local use.

    Since:
    JDK 1.2, HSQLDB 1.7.2
    Author:
    james house jhouse@part.net, boucherb@users
    • Constructor Summary

      Constructors 
      Constructor Description
      jdbcBlob​(byte[] data)
      Constructs a new jdbcBlob instance wrapping the given octet sequence.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void free()  
      java.io.InputStream getBinaryStream()
      Retrieves the BLOB value designated by this Blob instance as a stream.
      java.io.InputStream getBinaryStream​(long pos, long length)  
      byte[] getBytes​(long pos, int length)
      Retrieves all or part of the BLOB value that this Blob object represents, as an array of bytes.
      long length()
      Returns the number of bytes in the BLOB value designated by this Blob object.
      long position​(byte[] pattern, long start)
      Retrieves the byte position at which the specified byte array pattern begins within the BLOB value that this Blob object represents.
      long position​(java.sql.Blob pattern, long start)
      Retrieves the byte position in the BLOB value designated by this Blob object at which pattern begins.
      java.io.OutputStream setBinaryStream​(long pos)
      Retrieves a stream that can be used to write to the BLOB value that this Blob object represents.
      int setBytes​(long pos, byte[] bytes)
      Writes the given array of bytes to the BLOB value that this Blob object represents, starting at position pos, and returns the number of bytes written.
      int setBytes​(long pos, byte[] bytes, int offset, int len)
      Writes all or part of the given byte array to the BLOB value that this Blob object represents and returns the number of bytes written.
      void truncate​(long len)
      Truncates the BLOB value that this Blob object represents to be len bytes in length.
      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • jdbcBlob

        public jdbcBlob​(byte[] data)
                 throws java.sql.SQLException
        Constructs a new jdbcBlob instance wrapping the given octet sequence.

        This constructor is used internally to retrieve result set values as Blob objects, yet it must be public to allow access from other packages. As such (in the interest of efficiency) this object maintains a reference to the given octet sequence rather than making a copy; special care should be taken by extenal clients never to use this constructor with a byte array object that may later be modified extenally.

        Parameters:
        data - the octet sequence representing the Blob value
        Throws:
        java.sql.SQLException - if the argument is null
    • Method Detail

      • length

        public long length()
                    throws java.sql.SQLException
        Returns the number of bytes in the BLOB value designated by this Blob object.
        Specified by:
        length in interface java.sql.Blob
        Returns:
        length of the BLOB in bytes
        Throws:
        java.sql.SQLException - if there is an error accessing the length of the BLOB
        Since:
        JDK 1.2, HSQLDB 1.7.2
      • getBytes

        public byte[] getBytes​(long pos,
                               int length)
                        throws java.sql.SQLException
        Retrieves all or part of the BLOB value that this Blob object represents, as an array of bytes. This byte array contains up to length consecutive bytes starting at position pos.

        HSQLDB-Specific Information:

        The official specification above is ambiguous in that it does not precisely indicate the policy to be observed when pos > this.length() - length. One policy would be to retrieve the octets from pos to this.length(). Another would be to throw an exception. HSQLDB observes the later policy.

        Specified by:
        getBytes in interface java.sql.Blob
        Parameters:
        pos - the ordinal position of the first byte in the BLOB value to be extracted; the first byte is at position 1
        length - the number of consecutive bytes to be copied
        Returns:
        a byte array containing up to length consecutive bytes from the BLOB value designated by this Blob object, starting with the byte at position pos
        Throws:
        java.sql.SQLException - if there is an error accessing the BLOB value
        Since:
        JDK 1.2, HSQLDB 1.7.2
        See Also:
        setBytes(long, byte[])
      • getBinaryStream

        public java.io.InputStream getBinaryStream()
                                            throws java.sql.SQLException
        Retrieves the BLOB value designated by this Blob instance as a stream.
        Specified by:
        getBinaryStream in interface java.sql.Blob
        Returns:
        a stream containing the BLOB data
        Throws:
        java.sql.SQLException - if there is an error accessing the BLOB value
        Since:
        JDK 1.2, HSQLDB 1.7.2
        See Also:
        setBinaryStream(long)
      • position

        public long position​(byte[] pattern,
                             long start)
                      throws java.sql.SQLException
        Retrieves the byte position at which the specified byte array pattern begins within the BLOB value that this Blob object represents. The search for pattern begins at position start.

        Specified by:
        position in interface java.sql.Blob
        Parameters:
        pattern - the byte array for which to search
        start - the position at which to begin searching; the first position is 1
        Returns:
        the position at which the pattern appears, else -1
        Throws:
        java.sql.SQLException - if there is an error accessing the BLOB
        Since:
        JDK 1.2, HSQLDB 1.7.2
      • position

        public long position​(java.sql.Blob pattern,
                             long start)
                      throws java.sql.SQLException
        Retrieves the byte position in the BLOB value designated by this Blob object at which pattern begins. The search begins at position start.
        Specified by:
        position in interface java.sql.Blob
        Parameters:
        pattern - the Blob object designating the BLOB value for which to search
        start - the position in the BLOB value at which to begin searching; the first position is 1
        Returns:
        the position at which the pattern begins, else -1
        Throws:
        java.sql.SQLException - if there is an error accessing the BLOB value
        Since:
        JDK 1.2, HSQLDB 1.7.2
      • setBytes

        public int setBytes​(long pos,
                            byte[] bytes)
                     throws java.sql.SQLException
        Writes the given array of bytes to the BLOB value that this Blob object represents, starting at position pos, and returns the number of bytes written.

        HSQLDB-Specific Information:

        HSLQDB 1.7.2 does not support this feature.

        Calling this method always throws an SQLException.

        Specified by:
        setBytes in interface java.sql.Blob
        Parameters:
        pos - the position in the BLOB object at which to start writing
        bytes - the array of bytes to be written to the BLOB value that this Blob object represents
        Returns:
        the number of bytes written
        Throws:
        java.sql.SQLException - if there is an error accessing the BLOB value
        Since:
        JDK 1.4, HSQLDB 1.7.2
        See Also:
        getBytes(long, int)
      • setBytes

        public int setBytes​(long pos,
                            byte[] bytes,
                            int offset,
                            int len)
                     throws java.sql.SQLException
        Writes all or part of the given byte array to the BLOB value that this Blob object represents and returns the number of bytes written. Writing starts at position pos in the BLOB value; len bytes from the given byte array are written.

        HSQLDB-Specific Information:

        HSLQDB 1.7.2 does not support this feature.

        Calling this method always throws an SQLException.

        Specified by:
        setBytes in interface java.sql.Blob
        Parameters:
        pos - the position in the BLOB object at which to start writing
        bytes - the array of bytes to be written to this BLOB object
        offset - the offset into the array bytes at which to start reading the bytes to be set
        len - the number of bytes to be written to the BLOB value from the array of bytes bytes
        Returns:
        the number of bytes written
        Throws:
        java.sql.SQLException - if there is an error accessing the BLOB value
        Since:
        JDK 1.4, HSQLDB 1.7.2
        See Also:
        getBytes(long, int)
      • setBinaryStream

        public java.io.OutputStream setBinaryStream​(long pos)
                                             throws java.sql.SQLException
        Retrieves a stream that can be used to write to the BLOB value that this Blob object represents. The stream begins at position pos.

        HSQLDB-Specific Information:

        HSQLDB 1.7.2 does not support this feature.

        Calling this method always throws an SQLException.

        Specified by:
        setBinaryStream in interface java.sql.Blob
        Parameters:
        pos - the position in the BLOB value at which to start writing
        Returns:
        a java.io.OutputStream object to which data can be written
        Throws:
        java.sql.SQLException - if there is an error accessing the BLOB value
        Since:
        JDK 1.4, HSQLDB 1.7.2
        See Also:
        getBinaryStream()
      • truncate

        public void truncate​(long len)
                      throws java.sql.SQLException
        Truncates the BLOB value that this Blob object represents to be len bytes in length.

        HSQLDB-Specific Information:

        This operation affects only the client-side value; it has no effect upon the value as it is stored in the database.

        Specified by:
        truncate in interface java.sql.Blob
        Parameters:
        len - the length, in bytes, to which the BLOB value that this Blob object represents should be truncated
        Throws:
        java.sql.SQLException - if there is an error accessing the BLOB value
        Since:
        JDK 1.4, HSQLDB 1.7.2
      • free

        public void free()
                  throws java.sql.SQLException
        Specified by:
        free in interface java.sql.Blob
        Throws:
        java.sql.SQLException
      • getBinaryStream

        public java.io.InputStream getBinaryStream​(long pos,
                                                   long length)
                                            throws java.sql.SQLException
        Specified by:
        getBinaryStream in interface java.sql.Blob
        Throws:
        java.sql.SQLException