villa.java

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  }
  /**
   * Delete a record.
   * @param key a byte array of a key.
   * @throws VillaException if an error occures or no record corresponds.
   * @note When the key of duplicated records is specified, the first record of the same key
   * is deleted.  The cursor becomes unavailable due to updating database.
   */
  public void out(byte[] key) throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      if(vlout(index, key, key.length) == 0) throw new VillaException(vlecode());
    }
  }
  /**
   * Delete a record composed of serializable objects.
   * The same as `out(qdbm.Util.serialize(key))'.
   * @see #out(byte[])
   * @note If serialization is failed, an instance of `VillaException' is thrown.
   */
  public void outobj(Object key) throws VillaException {
    byte[] kbuf = Util.serialize(key);
    if(kbuf == null) throw new VillaException();
    out(kbuf);
  }
  /**
   * Retrieve a record.
   * @param key a byte array of a key.
   * @return a byte array of the value of the corresponding record.
   * @throws VillaException if an error occures, no record corresponds.
   * @note When the key of duplicated records is specified, the value of the first record of
   * the same key is selected.
   */
  public byte[] get(byte[] key) throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      byte[] val = vlget(index, key, key.length);
      if(val == null) throw new VillaException(vlecode());
      return val;
    }
  }
  /**
   * Retrieve a record composed of serializable objects.
   * The same as `qdbm.Util.deserialize(get(qdbm.Util.serialize(key)))'.
   * @see #get(byte[])
   * @note If serialization is failed, an instance of `VillaException' is thrown.
   */
  public Object getobj(Object key) throws VillaException {
    byte[] kbuf = Util.serialize(key);
    if(kbuf == null) throw new VillaException();
    Object val = Util.deserialize(get(kbuf));
    if(val == null) throw new VillaException();
    return val;
  }
  /**
   * Get the number of records corresponding a key.
   * @param key a byte array of a key.
   * @return the number of corresponding records.  If no record corresponds, 0 is returned.
   * @throws VillaException if an error occures.
   */
  public int vnum(byte[] key) throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      int rv = vlvnum(index, key, key.length);
      if(rv == -1) throw new VillaException(vlecode());
      return rv;
    }
  }
  /**
   * Get the number of records corresponding a key, composed of serializable objects.
   * The same as `vnum(qdbm.Util.serialize(key))'.
   * @see #vnum(byte[])
   * @note If serialization is failed, an instance of `VillaException' is thrown.
   */
  public int vnumobj(Object key) throws VillaException {
    byte[] kbuf = Util.serialize(key);
    if(kbuf == null) throw new VillaException();
    return vnum(kbuf);
  }
  /**
   * Move the cursor to the first record.
   * @throws VillaException if an error occures or there is no record in the database.
   */
  public void curfirst() throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      if(vlcurfirst(index) == 0) throw new VillaException(vlecode());
    }
  }
  /**
   * Move the cursor to the last record.
   * @throws VillaException if an error occures or there is no record in the database.
   */
  public void curlast() throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      if(vlcurlast(index) == 0) throw new VillaException(vlecode());
    }
  }
  /**
   * Move the cursor to the next record.
   * @throws VillaException if an error occures or there is no previous record.
   */
  public void curprev() throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      if(vlcurprev(index) == 0) throw new VillaException(vlecode());
    }
  }
  /**
   * Move the cursor to the next record.
   * @throws VillaException if an error occures or there is no next record.
   */
  public void curnext() throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      if(vlcurnext(index) == 0) throw new VillaException(vlecode());
    }
  }
  /**
   * Move the cursor to positon around a record.
   * @param key a byte array of a key.
   * @param jmode detail adjustment: `Villa.JFORWARD', which means that the cursor is set to
   * the first record of the same key and that the cursor is set to the next substitute if
   * completely matching record does not exist, `Villa.JBACKWARD', which means that the cursor
   * is set to the last record of the same key and that the cursor is set to the previous
   * substitute if completely matching record does not exist.
   * @throws VillaException if an error occures or there is no record corresponding the condition.
   */
  public void curjump(byte[] key, int jmode) throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      if(vlcurjump(index, key, key.length, jmode) == 0) throw new VillaException(vlecode());
    }
  }
  /**
   * Move the cursor to positon around a record for stepping forward.
   * The same as `curjump(key, Villa.JFORFARD)'.
   * @see #curjump(byte[], int)
   */
  public void curjump(byte[] key) throws VillaException {
    curjump(key, JFORWARD);
  }
  /**
   * Move the cursor to positon around a record composed of serializable objects.
   * The same as `curjump(qdbm.Util.serialize(key), jmode)'.
   * @see #curjump(byte[], int)
   * @note If serialization is failed, an instance of `VillaException' is thrown.
   */
  public void curjumpobj(Object key, int jmode) throws VillaException {
    byte[] kbuf = Util.serialize(key);
    if(kbuf == null) throw new VillaException();
    curjump(kbuf, jmode);
  }
  /**
   * Get the key of the record where the cursor is.
   * @throws VillaException if an error occures or no record corresponds to the cursor.
   */
  public byte[] curkey() throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      byte[] val = vlcurkey(index);
      if(val == null) throw new VillaException(vlecode());
      return val;
    }
  }
  /**
   * Get the key of the record composed of serializable objects, where the cursor is.
   * The same as `qdbm.Util.deserialize(curkey())'.
   * @see #curkey()
   * @note If serialization is failed, an instance of `VillaException' is thrown.
   */
  public Object curkeyobj() throws VillaException {
    Object key = Util.deserialize(curkey());
    if(key == null) throw new VillaException();
    return key;
  }
  /**
   * Get the value of the record where the cursor is.
   * @throws VillaException if an error occures or no record corresponds to the cursor.
   */
  public byte[] curval() throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      byte[] val = vlcurval(index);
      if(val == null) throw new VillaException(vlecode());
      return val;
    }
  }
  /**
   * Get the value of the record where the cursor is.
   * The same as `qdbm.Util.deserialize(curval())'.
   * @see #curval()
   * @note If serialization is failed, an instance of `VillaException' is thrown.
   */
  public Object curvalobj() throws VillaException {
    Object val = Util.deserialize(curval());
    if(val == null) throw new VillaException();
    return val;
  }
  /**
   * Set the tuning parameters for performance.
   * @param lrecmax the max number of records in a leaf node of B+ tree.  If it is not more
   * than 0, the default value is specified.
   * @param nidxmax the max number of indexes in a non-leaf node of B+ tree.  If it is not more
   * than 0, the default value is specified.
   * @param lcnum the max number of caching leaf nodes.  If it is not more than 0, the default
   * value is specified.
   * @param ncnum the max number of caching non-leaf nodes.  If it is not more than 0, the
   * default value is specified.
   * @throws VillaException if an error occures.
   * @note The default setting is equivalent to `settuning(49, 192, 1024, 512)'.  Because tuning
   * paremeters are not saved in a database, you should specify them every opening a database.
   */
  public void settuning(int lrecmax, int nidxmax, int lcnum, int ncnum) throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      vlsettuning(index, lrecmax, nidxmax, lcnum, ncnum);
    }
  }
  /**
   * Synchronize updating contents with the file and the device.
   * @throws VillaException if an error occures.
   * @note This method is useful when another process uses the connected database file.  This
   * method shuold not be used while the transaction is activated.
   */
  public void sync() throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      if(vlsync(index) == 0) throw new VillaException(vlecode());
    }
  }
  /**
   * Optimize the database.
   * @throws VillaException if an error occures.
   * @note In an alternating succession of deleting and storing with overwrite or concatenate,
   * dispensable regions accumulate.  This method is useful to do away with them.  This method
   * shuold not be used while the transaction is activated.
   */
  public void optimize() throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      if(vloptimize(index) == 0) throw new VillaException(vlecode());
    }
  }
  /**
   * Get the name of the database.
   * @return the string of the name of the database.
   * @throws VillaException if an error occures.
   */
  public String name() throws VillaException {
    if(index < 0) throw new VillaException();
    synchronized(ADBM.class){
      String buf = vlname(index);
      if(buf == null) throw new VillaException(vlecode());
      return buf;
    }
  }
  /**
   * Get the size of the database file.
   * @return the size of the database file.
   * @throws VillaException if an error occures.
   * @note Because of the I/O buffer, the return value may be less than the real size.