sql-dk: java/sql-dk/src/info/globalcode/sql/dk/formatting/TabularPrefetchingFormatter.java@da1e38386d84

     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;

    20 import java.util.ArrayList;

    21 import java.util.List;

    23 /**

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

    25  * {@linkplain #writeEndResultSet()}.

    26  *

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

    28  *

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

    30  */

    31 public class TabularPrefetchingFormatter extends TabularFormatter {

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

    34 	private ColumnsHeader currentHeader;

    35 	private List<Object[]> currentResultSet;

    36 	private Object[] currentRow;

    37 	private int currentColumnsCount;

    38 	private boolean prefetchDone = false;

    40 	public TabularPrefetchingFormatter(FormatterContext formatterContext) {

    41 		super(formatterContext);

    42 	}

    44 	@Override

    45 	protected int getCurrentColumnsCount() {

    46 		if (prefetchDone) {

    47 			return super.getCurrentColumnsCount();

    48 		} else {

    49 			return currentColumnsCount;

    50 		}

    51 	}

    53 	@Override

    54 	public void writeStartResultSet(ColumnsHeader header) {

    55 		currentResultSet = new ArrayList<>();

    56 		currentHeader = header;

    57 		initColumnWidths(header.getColumnCount());

    58 	}

    60 	@Override

    61 	public void writeStartRow() {

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

    63 		currentResultSet.add(currentRow);

    64 		currentColumnsCount = 0;

    65 	}

    67 	@Override

    68 	public void writeColumnValue(Object value) {

    69 		currentRow[currentColumnsCount] = value;

    70 		currentColumnsCount++;

    71 		String textRepresentation = toString(value);

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

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

    74 	}

    76 	@Override

    77 	public void writeEndRow() {

    78 		// do nothing

    79 	}

    81 	@Override

    82 	public void writeEndResultSet() {

    83 		prefetchDone = true;

    85 		super.writeStartResultSet(currentHeader);

    87 		for (Object[] row : currentResultSet) {

    88 			super.writeStartRow();

    89 			for (Object cell : row) {

    90 				super.writeColumnValue(cell);

    91 			}

    92 			super.writeEndRow();

    93 		}

    95 		currentColumnsCount = 0;

    96 		currentHeader = null;

    97 		currentRow = null;

    98 		currentResultSet = null;

    99 		super.writeEndResultSet();

   100 		prefetchDone = false;

   101 	}

   102 }

author	František Kučera <franta-hg@frantovo.cz>
	Tue, 07 Jan 2014 21:54:59 +0100
branch	v_0
changeset 142	da1e38386d84
parent 88	102ba0fcb07f
child 155	eb3676c6929b
permissions	-rw-r--r--