java/sql-dk/src/info/globalcode/sql/dk/formatting/TabularPrefetchingFormatter.java
author František Kučera <franta-hg@frantovo.cz>
Sat, 28 Dec 2013 20:36:29 +0100
branchv_0
changeset 92 1399ac70a5bd
parent 88 102ba0fcb07f
child 142 da1e38386d84
permissions -rw-r--r--
support all types from java.sql.Types.Types
     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 info.globalcode.sql.dk.Parameter;
    21 import java.util.ArrayList;
    22 import java.util.List;
    23 
    24 /**
    25  * Prefetches whole result set and computes column widths. Whole table is flushed at once in
    26  * {@linkplain #writeEndResultSet()}.
    27  *
    28  * Long values will not overflow the cells, but whole result set must be loaded into memory.
    29  *
    30  * @author Ing. František Kučera (frantovo.cz)
    31  */
    32 public class TabularPrefetchingFormatter extends TabularFormatter {
    33 
    34 	public static final String NAME = "tabular-prefetching"; // bash-completion:formatter
    35 	private String currentSql;
    36 	private List<? extends Parameter> currentParameters;
    37 	private ColumnsHeader currentHeader;
    38 	private List<Object[]> currentResultSet;
    39 	private Object[] currentRow;
    40 	private int currentColumnsCount;
    41 	private boolean prefetchDone = false;
    42 
    43 	public TabularPrefetchingFormatter(FormatterContext formatterContext) {
    44 		super(formatterContext);
    45 	}
    46 
    47 	@Override
    48 	protected int getCurrentColumnsCount() {
    49 		if (prefetchDone) {
    50 			return super.getCurrentColumnsCount();
    51 		} else {
    52 			return currentColumnsCount;
    53 		}
    54 	}
    55 
    56 	@Override
    57 	public void writeStartResultSet() {
    58 		currentResultSet = new ArrayList<>();
    59 	}
    60 
    61 	@Override
    62 	public void writeQuery(String sql) {
    63 		currentSql = sql;
    64 	}
    65 
    66 	@Override
    67 	public void writeParameters(List<? extends Parameter> parameters) {
    68 		currentParameters = parameters;
    69 	}
    70 
    71 	@Override
    72 	public void writeColumnsHeader(ColumnsHeader header) {
    73 		currentHeader = header;
    74 		initColumnWidths(header.getColumnCount());
    75 	}
    76 
    77 	@Override
    78 	public void writeStartRow() {
    79 		currentRow = new Object[currentHeader.getColumnCount()];
    80 		currentResultSet.add(currentRow);
    81 		currentColumnsCount = 0;
    82 	}
    83 
    84 	@Override
    85 	public void writeColumnValue(Object value) {
    86 		currentRow[currentColumnsCount] = value;
    87 		currentColumnsCount++;
    88 		String textRepresentation = toString(value);
    89 		/** TODO: count only printable characters (currently not an issue) */
    90 		updateColumnWidth(currentColumnsCount, textRepresentation.length());
    91 	}
    92 
    93 	@Override
    94 	public void writeEndRow() {
    95 		// do nothing
    96 	}
    97 
    98 	@Override
    99 	public void writeEndResultSet() {
   100 		prefetchDone = true;
   101 
   102 		super.writeStartResultSet();
   103 		super.writeQuery(currentSql);
   104 		super.writeParameters(currentParameters);
   105 		super.writeColumnsHeader(currentHeader);
   106 
   107 		for (Object[] row : currentResultSet) {
   108 			super.writeStartRow();
   109 			for (Object cell : row) {
   110 				super.writeColumnValue(cell);
   111 			}
   112 			super.writeEndRow();
   113 		}
   114 
   115 		currentColumnsCount = 0;
   116 		currentSql = null;
   117 		currentParameters = null;
   118 		currentHeader = null;
   119 		currentRow = null;
   120 		currentResultSet = null;
   121 		super.writeEndResultSet();
   122 		prefetchDone = false;
   123 	}
   124 }