com.softicar.platform.common.container.matrix.AsciiTable Maven / Gradle / Ivy
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package com.softicar.platform.common.container.matrix;
import com.softicar.platform.common.string.Padding;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
/**
* A simple table that can be printed out into text, using ASCII characters.
*
* This table has a fixed number of columns that are defined on construction.
* Adding cells to this table fills up the current row and will automatically
* start the next row, when the preceding row is full.
*
* The first row is automatically treated as the headline.
*
* @author Oliver Richers
*/
public class AsciiTable {
private static final String EOL = "\r\n";
private final List> rows = new ArrayList<>();
private final Integer colCount;
private List currentRow;
/**
* The alignment of a table cell.
*
* @author Oliver Richers
*/
public static enum Alignment {
ALIGN_LEFT,
ALIGN_RIGHT,
ALIGN_CENTER;
}
/**
* Constructs a new table with the specified number of columns.
*
* The first row will be treated as headline automatically.
*
* @param colCount
* the number of table columns
*/
public AsciiTable(int colCount) {
this.colCount = colCount;
}
/**
* Constructs a new table with the specified column names.
*
* The specified columns names will be used as column headlines and the
* number of the names automatically determines the number of columns in
* this table.
*
* @param columns
* the names of the table columns
*/
public AsciiTable(String...columns) {
this.colCount = columns.length;
for (String column: columns) {
add(column, Alignment.ALIGN_CENTER);
}
}
/**
* Returns the number of columns in this table.
*
* @return column count
*/
public int getColumntCount() {
return colCount;
}
public Collection> getRows() {
return Collections.unmodifiableCollection(rows);
}
/**
* Adds a new cell to this table with automatically determined alignment.
*
* The specified object will be converted into string, by calling its
* toString() method. A null value will be converted into the
* string null.
*
* If the specified object is inserted into the first row of the table,
* which is the headline row, the text will be centered. Otherwise, if the
* object is an instance of {@link Number}, the text will be aligned to the
* right, else to the left. If you need a different alignment strategy, you
* can call {@link #add(Object, Alignment)}, instead.
*
* @param object
* the object to insert as a new table cell
* @return this table (for chaining)
*/
public AsciiTable add(Object object) {
if (isInHeadline()) {
return add(object, Alignment.ALIGN_CENTER);
} else if (object instanceof Number) {
return add(object, Alignment.ALIGN_RIGHT);
} else {
return add(object, Alignment.ALIGN_LEFT);
}
}
private boolean isInHeadline() {
return currentRow == null || rows.size() == 1 && currentRow.size() < colCount;
}
/**
* Adds a new cell to this table with the specified alignment.
*
* The specified object will be converted into string, by calling its
* toString() method. A null value will be converted into the
* string null.
*
* @param object
* the object to insert as a new table cell
* @param alignment
* the alignment to use for the cell
* @return this table (for chaining)
*/
public AsciiTable add(Object object, Alignment alignment) {
if (isNeedNewRow()) {
rows.add(currentRow = new ArrayList<>());
}
currentRow.add(new AsciiTableCell("" + object, alignment));
return this;
}
private boolean isNeedNewRow() {
return currentRow == null || currentRow.size() == colCount;
}
@Override
public String toString() {
int rowCount = rows.size();
// init widths to zero
List widths = new ArrayList<>();
for (int c = 0; c != colCount; ++c) {
widths.add(0);
}
// compute widths of columns
for (int r = 0; r < rowCount; ++r) {
for (int c = 0; c != colCount; ++c) {
widths.set(c, Math.max(widths.get(c), rows.get(r).get(c).getWidth()));
}
}
// generate table
StringBuilder sb = new StringBuilder();
generateSeparator(sb, widths);
generateRow(sb, rows.get(0), widths);
generateSeparator(sb, widths);
for (int i = 1; i < rowCount; ++i) {
generateRow(sb, rows.get(i), widths);
}
generateSeparator(sb, widths);
return sb.toString();
}
private static void generateSeparator(StringBuilder sb, Collection widths) {
sb.append("+");
for (Integer width: widths) {
sb.append(Padding.generate('-', 2 + width));
sb.append("+");
}
sb.append(EOL);
}
private static void generateRow(StringBuilder sb, List cells, List widths) {
sb.append("|");
for (int i = 0; i != cells.size(); ++i) {
sb.append(" ");
cells.get(i).append(sb, widths.get(i));
sb.append(" |");
}
sb.append(EOL);
}
}