1 /**

     2  * SQL-DK

     3  * Copyright © 2013 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.formatting;

    19 

    20 import java.util.ArrayList;

    21 import java.util.List;

    22 

    23 /**

    24  * <p>

    25  * Prefetches whole result set and computes column widths. Whole table is flushed at once in

    26  * {@linkplain #writeEndResultSet()}.

    27  * </p>

    28  *

    29  * <p>

    30  * Long values will not overflow the cells, but whole result set must be loaded into the memory.

    31  * </p>

    32  *

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

    34  */

    35 public class TabularPrefetchingFormatter extends TabularFormatter {

    36 

    37 	public static final String NAME = "tabular-prefetching"; // bash-completion:formatter

    38 	private ColumnsHeader currentHeader;

    39 	private List<Object[]> currentResultSet;

    40 	private Object[] currentRow;

    41 	private int currentColumnsCount;

    42 	private boolean prefetchDone = false;

    43 

    44 	public TabularPrefetchingFormatter(FormatterContext formatterContext) {

    45 		super(formatterContext);

    46 	}

    47 

    48 	@Override

    49 	protected int getCurrentColumnsCount() {

    50 		if (prefetchDone) {

    51 			return super.getCurrentColumnsCount();

    52 		} else {

    53 			return currentColumnsCount;

    54 		}

    55 	}

    56 

    57 	@Override

    58 	public void writeStartResultSet(ColumnsHeader header) {

    59 		currentResultSet = new ArrayList<>();

    60 		currentHeader = header;

    61 		initColumnWidths(header.getColumnCount());

    62 	}

    63 

    64 	@Override

    65 	public void writeStartRow() {

    66 		currentRow = new Object[currentHeader.getColumnCount()];

    67 		currentResultSet.add(currentRow);

    68 		currentColumnsCount = 0;

    69 	}

    70 

    71 	@Override

    72 	public void writeColumnValue(Object value) {

    73 		currentRow[currentColumnsCount] = value;

    74 		currentColumnsCount++;

    75 		String textRepresentation = toString(value);

    76 		/** TODO: count only printable characters (currently not an issue) */

    77 		updateColumnWidth(currentColumnsCount, textRepresentation.length());

    78 	}

    79 

    80 	@Override

    81 	public void writeEndRow() {

    82 		// do nothing

    83 	}

    84 

    85 	@Override

    86 	public void writeEndResultSet() {

    87 		prefetchDone = true;

    88 

    89 		postprocessPrefetchedResultSet(currentHeader, currentResultSet);

    90 

    91 		super.writeStartResultSet(currentHeader);

    92 

    93 		for (Object[] row : currentResultSet) {

    94 			super.writeStartRow();

    95 			for (Object cell : row) {

    96 				super.writeColumnValue(cell);

    97 			}

    98 			super.writeEndRow();

    99 		}

   100 

   101 		currentColumnsCount = 0;

   102 		currentHeader = null;

   103 		currentRow = null;

   104 		currentResultSet = null;

   105 		super.writeEndResultSet();

   106 		prefetchDone = false;

   107 	}

   108 

   109 	/**

   110 	 * Optional post-processing – override in sub-classes if needed.

   111 	 * Don't forget to {@linkplain #updateColumnWidth(int, int)}

   112 	 *

   113 	 * @param currentHeader

   114 	 * @param currentResultSet

   115 	 */

   116 	protected void postprocessPrefetchedResultSet(ColumnsHeader currentHeader, List<Object[]> currentResultSet) {

   117 	}

   118 

   119 }