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Java Text Table Formatter is a Java library that renders tables made of characters.
The user add cells and can add format characteristics like predefined/custom table styles, text alignment, abbreviation, column width, border types, colspan, etc.
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package org.nocrala.tools.texttablefmt;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.nocrala.tools.utils.Log;
/**
*
* Text table generator with reduced memory usage. This class will generate text
* tables like:
*
*
*
*
* +---------+-----------+----------+--------+
* |Country | Population|Area (km2)| Density|
* +---------+-----------+----------+--------+
* |Chile | 17 000 000| 1 250 000| 13.60|
* |Argentina| 50 000 000| 3 000 000| 16.67|
* |Brasil | 80 000 000| 5 000 000| 16.00|
* +---------+-----------+----------+--------+
* |Total |147 000 000| 9 250 000| 15.89|
* +---------+-----------+----------+--------+
*
*
*
* where the border styles, shown borders/separators, column widths, alignments
* and other are configurable.
*
*
*
* Cells are added using the addCell() method and the table is
* finished using the finishTable() method.
*
*
*
* This class uses a reduced memory footprint, since it writes rows to the
* Appendable provided object each time a row is completed.
* Therefore it's suitable for rendering large tables.
*
*
*
* All column widths default to 10 characters wide. Change this widths as
* desired BEFORE adding any cell, using the method
* setColumnWidth().
*
*
*
* After adding all cells use the method finishTable() to flush any
* remaining characters to the Appendable object.
*
*
*
* As an example, the following code
*
*
*
*
* CellStyle cs = new CellStyle(HorizontalAlign.left, AbbreviationStyle.crop,
* NullStyle.emptyString);
* StringBuffer sb = new StringBuffer();
* StreamingTable t = new StreamingTable(sb, 2, BorderStyle.CLASSIC,
* ShownBorders.ALL, false, "");
* t.addCell("abcdef", cs);
* t.addCell("123456", cs);
* t.addCell("mno", cs);
* t.addCell("45689", cs);
* t.addCell("xyztuvw", cs);
* t.addCell("01234567", cs);
* t.finishTable();
* System.out.println(sb.toString());
*
*
*
* will generate the table:
*
*
*
*
* +-------+--------+
* |abcdef |123456 |
* +-------+--------+
* |mno |45689 |
* +-------+--------+
* |xyztuvw|01234567|
* +-------+--------+
*
*
*
* The generated table can be customized using a BorderStyle,
* ShownBorders and cell widths. Besides, cell rendering can be
* customized on a cell basis using CellStyles.
*
*
* @author valarcon
*
*/
public class StreamingTable {
private static final int DEFAULT_WIDTH = 10;
private Appendable appendable;
TableStyle tableStyle;
private List columns;
private int currentColumn;
private Row previousRow;
private Row currentRow;
private int currentRowPos;
/**
* Creates a streaming table that will write to an Appendable
* object using BorderStyle.CLASSIC and
* ShownBorders.SURROUND_HEADER_AND_COLUMNS, no XML escaping and
* no left margin.
*
* @param appendable
* Character stream where to write the rendered table.
* @param totalColumns
* Total columns of this table.
*/
public StreamingTable(final Appendable appendable, final int totalColumns) {
initialize(appendable, totalColumns);
this.tableStyle = new TableStyle(BorderStyle.CLASSIC,
ShownBorders.SURROUND_HEADER_AND_COLUMNS, false, 0, null);
}
/**
* Creates a streaming table that will write to an Appendable
* object using a specific border style, showing
* ShownBorders.SURROUND_HEADER_AND_COLUMNS separators, no XML
* escaping and no left margin.
*
* @param appendable
* Character stream where to write the rendered table.
* @param totalColumns
* Total columns of this table.
* @param borderStyle
* The border style to use when rendering the table.
*/
public StreamingTable(final Appendable appendable, final int totalColumns,
final BorderStyle borderStyle) {
initialize(appendable, totalColumns);
this.tableStyle = new TableStyle(borderStyle,
ShownBorders.SURROUND_HEADER_AND_COLUMNS, false, 0, null);
}
/**
* Creates a streaming table that will write to an Appendable
* object using specific border style and shown borders, no XML escaping and
* no left margin.
*
* @param appendable
* Character stream where to write the rendered table.
* @param totalColumns
* Total columns of this table.
* @param borderStyle
* The border style to use when rendering the table.
* @param shownBorders
* Specifies which borders will be rendered.
*/
public StreamingTable(final Appendable appendable, final int totalColumns,
final BorderStyle borderStyle, final ShownBorders shownBorders) {
initialize(appendable, totalColumns);
this.tableStyle = new TableStyle(borderStyle, shownBorders, false, 0, null);
}
/**
* Creates a streaming table that will write to an Appendable
* object using specific border style, shown borders and XML escaping and
* without left margin.
*
* @param appendable
* Character stream where to write the rendered table.
* @param totalColumns
* Total columns of this table.
* @param borderStyle
* The border style to use when rendering the table.
* @param shownBorders
* Specifies which borders will be rendered.
* @param escapeXml
* Specifies if the rendered text should be escaped using XML
* entities.
*/
public StreamingTable(final Appendable appendable, final int totalColumns,
final BorderStyle borderStyle, final ShownBorders shownBorders,
final boolean escapeXml) {
initialize(appendable, totalColumns);
this.tableStyle = new TableStyle(borderStyle, shownBorders, escapeXml, 0,
null);
}
/**
* Creates a streaming table that will write to an Appendable
* object using specific border style, shown borders, XML escaping and left
* margin.
*
* @param appendable
* Character stream where to write the rendered table.
* @param totalColumns
* Total columns of this table.
* @param borderStyle
* The border style to use when rendering the table.
* @param shownBorders
* Specifies which borders will be rendered.
* @param escapeXml
* Specifies if the rendered text should be escaped using XML
* entities.
* @param leftMargin
* Specifies how many blank spaces will be used as a left margin for
* the table.
*/
public StreamingTable(final Appendable appendable, final int totalColumns,
final BorderStyle borderStyle, final ShownBorders shownBorders,
final boolean escapeXml, final int leftMargin) {
initialize(appendable, totalColumns);
this.tableStyle = new TableStyle(borderStyle, shownBorders, escapeXml,
leftMargin, null);
}
/**
* Creates a streaming table that will write to an Appendable
* object using specific border style, shown borders, XML escaping and left
* margin.
*
* @param appendable
* Character stream where to write the rendered table.
* @param totalColumns
* Total columns of this table.
* @param borderStyle
* The border style to use when rendering the table.
* @param shownBorders
* Specifies which borders will be rendered.
* @param escapeXml
* Specifies if the rendered text should be escaped using XML
* entities.
* @param prompt
* Text to use as left margin for the table.
*/
public StreamingTable(final Appendable appendable, final int totalColumns,
final BorderStyle borderStyle, final ShownBorders shownBorders,
final boolean escapeXml, final String prompt) {
initialize(appendable, totalColumns);
this.tableStyle = new TableStyle(borderStyle, shownBorders, escapeXml, 0,
prompt);
}
private void initialize(final Appendable writer, final int totalColumns) {
this.appendable = writer;
this.previousRow = null;
this.columns = new ArrayList();
for (int i = 0; i < totalColumns; i++) {
this.columns.add(new Column(i, DEFAULT_WIDTH));
}
this.currentColumn = 0;
this.currentRow = null;
this.currentRowPos = 0;
}
/**
* Sets the width of a specific column.
*
* @param col
* Column whose width will be set. First column is 0 (zero).
* @param width
* width of the column.
*/
public void setColumnWidth(final int col, final int width) {
this.columns.get(col).setWidth(width < 0 ? 0 : width);
}
/**
* Adds a cell with the default CellStyle.
*
* @param content
* Cell text.
* @throws IOException
* if it is not possible to output to the Appendable object.
*/
public void addCell(final String content) throws IOException {
addCell(content, new CellStyle());
}
/**
* Adds a cell with a colspan and the default CellStyle.
*
* @param content
* Cell text.
* @param colSpan
* Columns this cell will span through.
* @throws IOException
* if it is not possible to output to the Appendable object.
*/
public void addCell(final String content, final int colSpan)
throws IOException {
addCell(content, new CellStyle(), colSpan);
}
/**
* Adds a cell with a specific cell style.
*
* @param content
* Cell text.
* @param style
* Cell style to use when rendering the cell content.
* @throws IOException
* if it is not possible to output to the Appendable object.
*/
public void addCell(final String content, final CellStyle style)
throws IOException {
addCell(content, style, 1);
}
/**
* Adds a cell with a specific cell style and colspan.
*
* @param content
* Cell text.
* @param style
* Cell style to use when rendering the cell content.
* @param colSpan
* Columns this cell will span through.
* @throws IOException
* if it is not possible to output to the Appendable object.
*/
public void addCell(final String content, final CellStyle style,
final int colSpan) throws IOException {
if (this.currentRow == null) {
this.currentRow = new Row();
this.currentColumn = 0;
}
if (this.currentColumn >= this.columns.size()) {
renderRow(false);
this.previousRow = this.currentRow;
this.currentRow = new Row();
this.currentColumn = 0;
}
int adjColSpan = colSpan > 0 ? colSpan : 1;
this.currentRow.addCell(content, style, adjColSpan);
this.currentColumn = this.currentColumn + adjColSpan;
}
/**
* Finishes the table rendering and flushes any remaining characters to the
* Appendable object.
*
* @throws IOException
*/
public void finishTable() throws IOException {
if (this.currentRow != null) {
renderRow(true);
}
}
private void renderRow(final boolean isLast) throws IOException {
Log.debug("this.currentRow.getSize()=" + this.currentRow.getSize());
boolean isFirst = this.currentRowPos == 0;
boolean isSecond = this.currentRowPos == 1;
boolean isIntermediate = (this.currentRowPos > 1) && !isLast;
this.tableStyle.renderRow(this.appendable, this.currentRow,
this.previousRow, this.columns, isFirst, isSecond, isIntermediate,
isLast);
this.currentRowPos++;
}
int getTotalColumns() {
return this.columns.size();
}
Column getColumn(final int index) {
return this.columns.get(index);
}
}