java/sql-dk/src/main/java/info/globalcode/sql/dk/formatting/TabularPrefetchingFormatter.java
1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/java/sql-dk/src/main/java/info/globalcode/sql/dk/formatting/TabularPrefetchingFormatter.java Mon Mar 04 20:15:24 2019 +0100
1.3 @@ -0,0 +1,119 @@
1.4 +/**
1.5 + * SQL-DK
1.6 + * Copyright © 2013 František Kučera (frantovo.cz)
1.7 + *
1.8 + * This program is free software: you can redistribute it and/or modify
1.9 + * it under the terms of the GNU General Public License as published by
1.10 + * the Free Software Foundation, either version 3 of the License, or
1.11 + * (at your option) any later version.
1.12 + *
1.13 + * This program is distributed in the hope that it will be useful,
1.14 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
1.15 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1.16 + * GNU General Public License for more details.
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License
1.19 + * along with this program. If not, see <http://www.gnu.org/licenses/>.
1.20 + */
1.21 +package info.globalcode.sql.dk.formatting;
1.22 +
1.23 +import java.util.ArrayList;
1.24 +import java.util.List;
1.25 +
1.26 +/**
1.27 + * <p>
1.28 + * Prefetches whole result set and computes column widths. Whole table is flushed at once in
1.29 + * {@linkplain #writeEndResultSet()}.
1.30 + * </p>
1.31 + *
1.32 + * <p>
1.33 + * Long values will not overflow the cells, but whole result set must be loaded into the memory.
1.34 + * </p>
1.35 + *
1.36 + * @author Ing. František Kučera (frantovo.cz)
1.37 + */
1.38 +public class TabularPrefetchingFormatter extends TabularFormatter {
1.39 +
1.40 + public static final String NAME = "tabular-prefetching"; // bash-completion:formatter
1.41 + private ColumnsHeader currentHeader;
1.42 + private List<Object[]> currentResultSet;
1.43 + private Object[] currentRow;
1.44 + private int currentColumnsCount;
1.45 + private boolean prefetchDone = false;
1.46 +
1.47 + public TabularPrefetchingFormatter(FormatterContext formatterContext) {
1.48 + super(formatterContext);
1.49 + }
1.50 +
1.51 + @Override
1.52 + protected int getCurrentColumnsCount() {
1.53 + if (prefetchDone) {
1.54 + return super.getCurrentColumnsCount();
1.55 + } else {
1.56 + return currentColumnsCount;
1.57 + }
1.58 + }
1.59 +
1.60 + @Override
1.61 + public void writeStartResultSet(ColumnsHeader header) {
1.62 + currentResultSet = new ArrayList<>();
1.63 + currentHeader = header;
1.64 + initColumnWidths(header.getColumnCount());
1.65 + }
1.66 +
1.67 + @Override
1.68 + public void writeStartRow() {
1.69 + currentRow = new Object[currentHeader.getColumnCount()];
1.70 + currentResultSet.add(currentRow);
1.71 + currentColumnsCount = 0;
1.72 + }
1.73 +
1.74 + @Override
1.75 + public void writeColumnValue(Object value) {
1.76 + currentRow[currentColumnsCount] = value;
1.77 + currentColumnsCount++;
1.78 + String textRepresentation = toString(value);
1.79 + /** TODO: count only printable characters (currently not an issue) */
1.80 + updateColumnWidth(currentColumnsCount, textRepresentation.length());
1.81 + }
1.82 +
1.83 + @Override
1.84 + public void writeEndRow() {
1.85 + // do nothing
1.86 + }
1.87 +
1.88 + @Override
1.89 + public void writeEndResultSet() {
1.90 + prefetchDone = true;
1.91 +
1.92 + postprocessPrefetchedResultSet(currentHeader, currentResultSet);
1.93 +
1.94 + super.writeStartResultSet(currentHeader);
1.95 +
1.96 + for (Object[] row : currentResultSet) {
1.97 + super.writeStartRow();
1.98 + for (Object cell : row) {
1.99 + super.writeColumnValue(cell);
1.100 + }
1.101 + super.writeEndRow();
1.102 + }
1.103 +
1.104 + currentColumnsCount = 0;
1.105 + currentHeader = null;
1.106 + currentRow = null;
1.107 + currentResultSet = null;
1.108 + super.writeEndResultSet();
1.109 + prefetchDone = false;
1.110 + }
1.111 +
1.112 + /**
1.113 + * Optional post-processing – override in sub-classes if needed.
1.114 + * Don't forget to {@linkplain #updateColumnWidth(int, int)}
1.115 + *
1.116 + * @param currentHeader
1.117 + * @param currentResultSet
1.118 + */
1.119 + protected void postprocessPrefetchedResultSet(ColumnsHeader currentHeader, List<Object[]> currentResultSet) {
1.120 + }
1.121 +
1.122 +}