serialblob.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

        int i = 0;        
        long patlen = pattern.length;                
        
        while (pos < len) {     
            if (pattern[i] == buf[pos]) {                
                if (i + 1 == patlen) {
                    return (pos + 1) - (patlen - 1);
                }
                i++; pos++; // increment pos, and i
            } else if (pattern[i] != buf[pos]) {
                pos++; // increment pos only
            }                                    
        }        
        return -1; // not found
    }
    	
    /** 	 
     * Returns the position in this <code>SerialBlob</code> object where	
     * the given <code>Blob</code> object begins, starting the search at the	
     * specified position.	
     *	
     * @param pattern the <code>Blob</code> object for which to search; 	
     * @param start the position of the byte in this	
     *              <code>SerialBlob</code> object from which to begin 	
     *              the search; the first position is <code>1</code>;	
     *              must not be less than <code>1</code> nor greater than	
     *              the length of this <code>SerialBlob</code> object	
     * @return the position in this <code>SerialBlob</code> object	
     *         where the given <code>Blob</code> object begins, starting 	
     *         at the specified position; <code>-1</code> if the pattern is 
     *         not found or the given starting position is out of bounds;	     
     *         position numbering for the return value starts at <code>1</code>     
     * @throws SerialException if an error occurs when serializing the blob
     * @throws SQLException if there is an error accessing the <code>BLOB</code>
     *         value from the database     
     */
    public long position(Blob pattern, long start) 
       throws SerialException, SQLException {
        return position(pattern.getBytes(1, (int)(pattern.length())), start);
    }
    
    /**
     * Writes the given array of bytes to the <code>BLOB</code> value that
     * this <code>Blob</code> object represents, starting at position 
     * <code>pos</code>, and returns the number of bytes written.
     *
     * @param pos the position in the SQL <code>BLOB</code> value at which
     *     to start writing. The first position is <code>1</code>;	
     *     must not be less than <code>1</code> nor greater than	
     *     the length of this <code>SerialBlob</code> object.
     * @param bytes the array of bytes to be written to the <code>BLOB</code>
     *        value that this <code>Blob</code> object represents
     * @return the number of bytes written
     * @throws SerialException if there is an error accessing the
     *     <code>BLOB</code> value; or if an invalid position is set; if an 
     *     invalid offset value is set
     * @throws SQLException if there is an error accessing the <code>BLOB</code>
     *         value from the database     
     * @see #getBytes
     */
    public int setBytes(long pos, byte[] bytes) 
        throws SerialException, SQLException {
        return (setBytes(pos, bytes, 0, bytes.length));
    }
    
    /**
     * Writes all or part of the given <code>byte</code> array to the
     * <code>BLOB</code> value that this <code>Blob</code> object represents
     * and returns the number of bytes written.
     * Writing starts at position <code>pos</code> in the <code>BLOB</code>
     * value; <i>len</i> bytes from the given byte array are written.
     *
     * @param pos the position in the <code>BLOB</code> object at which
     *     to start writing. The first position is <code>1</code>;	
     *     must not be less than <code>1</code> nor greater than	
     *     the length of this <code>SerialBlob</code> object.
     * @param bytes the array of bytes to be written to the <code>BLOB</code>
     *     value
     * @param offset the offset in the <code>byte</code> array at which
     *     to start reading the bytes. The first offset position is
     *     <code>0</code>; must not be less than <code>0</code> nor greater
     *     than the length of the <code>byte</code> array
     * @param length the number of bytes to be written to the 
     *     <code>BLOB</code> value from the array of bytes <i>bytes</i>.
     *        
     * @return the number of bytes written
     * @throws SerialException if there is an error accessing the 
     *     <code>BLOB</code> value; if an invalid position is set; if an 
     *     invalid offset value is set; if number of bytes to be written
     *     is greater than the <code>SerialBlob</code> length; or the combined
     *     values of the length and offset is greater than the Blob buffer
     * @throws SQLException if there is an error accessing the <code>BLOB</code>
     *         value from the database.     
     * @see #getBytes
     */
    public int setBytes(long pos, byte[] bytes, int offset, int length) 
        throws SerialException, SQLException {
        
        if (offset < 0 || offset > bytes.length) {
            throw new SerialException("Invalid offset in byte array set");
        }            
        
        if (pos < 1 || pos > this.length()) {
            throw new SerialException("Invalid position in BLOB object set");
        }
                    
        if ((long)(length) > origLen) {
	    throw new SerialException("Buffer is not sufficient to hold the value");
	}    
        
        if ((length + offset) > bytes.length) {  
            throw new SerialException("Invalid OffSet. Cannot have combined offset " +
                "and length that is greater that the Blob buffer");            
        }                                       
        
        int i = 0;
        pos--; // correct to array indexing
        while ( i < length || (offset + i +1) < (bytes.length-offset) ) {
            this.buf[(int)pos + i] = bytes[offset + i ]; 
            i++;
        }
        return i;        
    }
    
    /**
     * Retrieves a stream that can be used to write to the <code>BLOB</code> 
     * value that this <code>Blob</code> object represents.  The stream begins
     * at position <code>pos</code>. This method forwards the 
     * <code>setBinaryStream()</code> call to the underlying <code>Blob</code> in 
     * the event that this <code>SerialBlob</code> object is instantiated with a 
     * <code>Blob</code>. If this <code>SerialBlob</code> is instantiated with
     * a <code>byte</code> array, a <code>SerialException</code> is thrown.
     *
     * @param pos the position in the <code>BLOB</code> value at which
     *        to start writing
     * @return a <code>java.io.OutputStream</code> object to which data can 
     *         be written
     * @throws SQLException if there is an error accessing the
     *            <code>BLOB</code> value
     * @throws SerialException if the SerialBlob in not instantiated with a 
     *     <code>Blob</code> object that supports <code>setBinaryStream()</code>
     * @see #getBinaryStream
     */
    public java.io.OutputStream setBinaryStream(long pos) 
        throws SerialException, SQLException {       
        if (this.blob.setBinaryStream(pos) != null) {
            return this.blob.setBinaryStream(pos);
        } else {
            throw new SerialException("Unsupported operation. SerialBlob cannot " +
                "return a writable binary stream, unless instantiated with a Blob object " +
                "that provides a setBinaryStream() implementation");
        }        
    }
    
    /**
     * Truncates the <code>BLOB</code> value that this <code>Blob</code>
     * object represents to be <code>len</code> bytes in length.
     *
     * @param length the length, in bytes, to which the <code>BLOB</code>
     *        value that this <code>Blob</code> object represents should be 
     *        truncated
     * @throws SerialException if there is an error accessing the Blob value;
     *     or the length to truncate is greater that the SerialBlob length     
     */
    public void truncate(long length) throws SerialException {
         
         if (length > len) {
            throw new SerialException
               ("Length more than what can be truncated");
         } else if((int)length == 0) { 
              buf = new byte[0];
              len = length;
         } else {      
              len = length;              
              buf = this.getBytes(1, (int)len);
         }  
    }
    
    
    /**
     * Returns an <code>InputStream</code> object that contains a partial <code>Blob</code> value, 
     * starting  with the byte specified by pos, which is length bytes in length.
     *
     * @param pos the offset to the first byte of the partial value to be retrieved.
     *  The first byte in the <code>Blob</code> is at position 1
     * @param length the length in bytes of the partial value to be retrieved
     * @return <code>InputStream</code> through which the partial <code>Blob</code> value can be read.
     * @throws SQLException if pos is less than 1 or if pos is greater than the number of bytes
     * in the <code>Blob</code> or if pos + length is greater than the number of bytes 
     * in the <code>Blob</code>
     *
     * @since 1.6
     */
    public InputStream getBinaryStream(long pos,long length) throws SQLException {
        throw new java.lang.UnsupportedOperationException("Not supported");
    }


    /**
     * This method frees the <code>Blob</code> object and releases the resources that it holds.
     * <code>Blob</code> object. The object is invalid once the <code>free</code>
     * method is called. If <code>free</code> is called multiple times, the subsequent
     * calls to <code>free</code> are treated as a no-op.
     * 
     * @throws SQLException if an error occurs releasing 
     * the Blob's resources
     * @since 1.6
     */
    public void free() throws SQLException {
        throw new java.lang.UnsupportedOperationException("Not supported");
    }
    /**
	 * The identifier that assists in the serialization of this <code>SerialBlob</code>
     * object.
     */

    static final long serialVersionUID = -8144641928112860441L;
}