diff -r 7e08730da258 -r 4a1864c3e867 java/sql-dk/src/main/java/info/globalcode/sql/dk/formatting/TabularPrefetchingFormatter.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/java/sql-dk/src/main/java/info/globalcode/sql/dk/formatting/TabularPrefetchingFormatter.java Mon Mar 04 20:15:24 2019 +0100 @@ -0,0 +1,119 @@ +/** + * SQL-DK + * Copyright © 2013 František Kučera (frantovo.cz) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +package info.globalcode.sql.dk.formatting; + +import java.util.ArrayList; +import java.util.List; + +/** + *

+ * Prefetches whole result set and computes column widths. Whole table is flushed at once in + * {@linkplain #writeEndResultSet()}. + *

+ * + *

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

+ * + * @author Ing. František Kučera (frantovo.cz) + */ +public class TabularPrefetchingFormatter extends TabularFormatter { + + public static final String NAME = "tabular-prefetching"; // bash-completion:formatter + private ColumnsHeader currentHeader; + private List currentResultSet; + private Object[] currentRow; + private int currentColumnsCount; + private boolean prefetchDone = false; + + public TabularPrefetchingFormatter(FormatterContext formatterContext) { + super(formatterContext); + } + + @Override + protected int getCurrentColumnsCount() { + if (prefetchDone) { + return super.getCurrentColumnsCount(); + } else { + return currentColumnsCount; + } + } + + @Override + public void writeStartResultSet(ColumnsHeader header) { + currentResultSet = new ArrayList<>(); + currentHeader = header; + initColumnWidths(header.getColumnCount()); + } + + @Override + public void writeStartRow() { + currentRow = new Object[currentHeader.getColumnCount()]; + currentResultSet.add(currentRow); + currentColumnsCount = 0; + } + + @Override + public void writeColumnValue(Object value) { + currentRow[currentColumnsCount] = value; + currentColumnsCount++; + String textRepresentation = toString(value); + /** TODO: count only printable characters (currently not an issue) */ + updateColumnWidth(currentColumnsCount, textRepresentation.length()); + } + + @Override + public void writeEndRow() { + // do nothing + } + + @Override + public void writeEndResultSet() { + prefetchDone = true; + + postprocessPrefetchedResultSet(currentHeader, currentResultSet); + + super.writeStartResultSet(currentHeader); + + for (Object[] row : currentResultSet) { + super.writeStartRow(); + for (Object cell : row) { + super.writeColumnValue(cell); + } + super.writeEndRow(); + } + + currentColumnsCount = 0; + currentHeader = null; + currentRow = null; + currentResultSet = null; + super.writeEndResultSet(); + prefetchDone = false; + } + + /** + * Optional post-processing – override in sub-classes if needed. + * Don't forget to {@linkplain #updateColumnWidth(int, int)} + * + * @param currentHeader + * @param currentResultSet + */ + protected void postprocessPrefetchedResultSet(ColumnsHeader currentHeader, List currentResultSet) { + } + +}