1 /**

     2  * SQL-DK

     3  * Copyright © 2014 František Kučera (frantovo.cz)

     4  *

     5  * This program is free software: you can redistribute it and/or modify

     6  * it under the terms of the GNU General Public License as published by

     7  * the Free Software Foundation, either version 3 of the License, or

     8  * (at your option) any later version.

     9  *

    10  * This program is distributed in the hope that it will be useful,

    11  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

    13  * GNU General Public License for more details.

    14  *

    15  * You should have received a copy of the GNU General Public License

    16  * along with this program. If not, see <http://www.gnu.org/licenses/>.

    17  */

    18 package info.globalcode.sql.dk.batch;

    19 

    20 import info.globalcode.sql.dk.Parameter;

    21 import info.globalcode.sql.dk.SQLCommand;

    22 import info.globalcode.sql.dk.SQLCommandNumbered;

    23 import java.io.DataInputStream;

    24 import java.io.InputStream;

    25 import static info.globalcode.sql.dk.batch.BatchConstants.*;

    26 import static info.globalcode.sql.dk.Functions.toHex;

    27 import info.globalcode.sql.dk.SQLType;

    28 import java.io.IOException;

    29 import java.util.ArrayList;

    30 import java.util.Arrays;

    31 import java.util.List;

    32 

    33 /**

    34  *

    35  * @author Ing. František Kučera (frantovo.cz)

    36  */

    37 public class BatchDecoder {

    38 

    39 	public Batch decode(InputStream in) throws BatchException {

    40 		return new BatchFromStream(new DataInputStream(in));

    41 	}

    42 

    43 	private class BatchFromStream implements Batch {

    44 

    45 		private DataInputStream in;

    46 		private boolean hasNext;

    47 

    48 		public BatchFromStream(DataInputStream in) throws BatchException {

    49 			this.in = in;

    50 			hasNext = verifyHeader();

    51 		}

    52 

    53 		@Override

    54 		public boolean hasNext() throws BatchException {

    55 			return hasNext;

    56 		}

    57 

    58 		@Override

    59 		public SQLCommand next() throws BatchException {

    60 			try {

    61 				String sql = readNextString();

    62 

    63 				int paramCount = in.readInt();

    64 				List<Parameter> parameters = new ArrayList<>(paramCount);

    65 

    66 				for (int i = 0; i < paramCount; i++) {

    67 					SQLType type = SQLType.valueOf(in.readInt());

    68 					String value = readNextString();

    69 					parameters.add(new Parameter(value, type));

    70 				}

    71 

    72 				hasNext = verifyHeader();

    73 

    74 				SQLCommand sqlCommand = new SQLCommandNumbered(sql, parameters);

    75 				return sqlCommand;

    76 			} catch (IOException e) {

    77 				throw new BatchException("Unable to read batch", e);

    78 			}

    79 		}

    80 

    81 		private String readNextString() throws IOException {

    82 			byte[] buffer = new byte[in.readInt()];

    83 			in.read(buffer);

    84 			return new String(buffer, CHARSET);

    85 		}

    86 

    87 		/**

    88 		 * @return true if correct batch header was found | false if EOF was found

    89 		 * @throws BatchException if unexpected data was found (not batch header nor EOF)

    90 		 */

    91 		private boolean verifyHeader() throws BatchException {

    92 			try {

    93 				byte[] buffer = new byte[BATCH_HEADER.length];

    94 				int bytesRead = in.read(buffer);

    95 

    96 				if (bytesRead == BATCH_HEADER.length && Arrays.equals(buffer, BATCH_HEADER)) {

    97 					return true;

    98 				} else if (bytesRead == -1) {

    99 					return false;

   100 				} else {

   101 					throw new BatchException("This is not SQL-DK batch: " + toHex(buffer));

   102 				}

   103 			} catch (IOException e) {

   104 				throw new BatchException("Unable to read batch header", e);

   105 			}

   106 		}

   107 	}

   108 }