/*
* Copyright (c) 2002-2012, the original author or authors.
*
* This software is distributable under the BSD license. See the terms of the
* BSD license in the documentation provided with this software.
*
* http://www.opensource.org/licenses/bsd-license.php
*/
package jline.console.completer;
import jline.console.ConsoleReader;
import jline.console.CursorBuffer;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.ResourceBundle;
import java.util.Set;
/**
* A {@link CompletionHandler} that deals with multiple distinct completions
* by outputting the complete list of possibilities to the console. This
* mimics the behavior of the
* <a href="http://www.gnu.org/directory/readline.html">readline</a> library.
*
* @author <a href="mailto:mwp1@cornell.edu">Marc Prud'hommeaux</a>
* @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
* @since 2.3
*/
public class CandidateListCompletionHandler
implements CompletionHandler
{
// TODO: handle quotes and escaped quotes && enable automatic escaping of whitespace
public boolean complete(final ConsoleReader reader, final List<CharSequence> candidates, final int pos) throws
IOException
{
CursorBuffer buf = reader.getCursorBuffer();
// if there is only one completion, then fill in the buffer
if (candidates.size() == 1) {
CharSequence value = candidates.get(0);
// fail if the only candidate is the same as the current buffer
if (value.equals(buf.toString())) {
return false;
}
setBuffer(reader, value, pos);
return true;
}
else if (candidates.size() > 1) {
String value = getUnambiguousCompletions(candidates);
setBuffer(reader, value, pos);
}
printCandidates(reader, candidates);
// redraw the current console buffer
reader.drawLine();
return true;
}
public static void setBuffer(final ConsoleReader reader, final CharSequence value, final int offset) throws
IOException
{
while ((reader.getCursorBuffer().cursor > offset) && reader.backspace()) {
// empty
}
reader.putString(value);
reader.setCursorPosition(offset + value.length());
}
/**
* Print out the candidates. If the size of the candidates is greater than the
* {@link ConsoleReader#getAutoprintThreshold}, they prompt with a warning.
*
* @param candidates the list of candidates to print
*/
public static void printCandidates(final ConsoleReader reader, Collection<CharSequence> candidates) throws
IOException
{
Set<CharSequence> distinct = new HashSet<CharSequence>(candidates);
if (distinct.size() > reader.getAutoprintThreshold()) {
//noinspection StringConcatenation
reader.print(Messages.DISPLAY_CANDIDATES.format(candidates.size()));
reader.flush();
int c;
String noOpt = Messages.DISPLAY_CANDIDATES_NO.format();
String yesOpt = Messages.DISPLAY_CANDIDATES_YES.format();
char[] allowed = {yesOpt.charAt(0), noOpt.charAt(0)};
while ((c = reader.readCharacter(allowed)) != -1) {
String tmp = new String(new char[]{(char) c});
if (noOpt.startsWith(tmp)) {
reader.println();
return;
}
else if (yesOpt.startsWith(tmp)) {
break;
}
else {
reader.beep();
}
}
}
// copy the values and make them distinct, without otherwise affecting the ordering. Only do it if the sizes differ.
if (distinct.size() != candidates.size()) {
Collection<CharSequence> copy = new ArrayList<CharSequence>();
for (CharSequence next : candidates) {
if (!copy.contains(next)) {
copy.add(next);
}
}
candidates = copy;
}
reader.println();
reader.printColumns(candidates);
}
/**
* Returns a root that matches all the {@link String} elements of the specified {@link List},
* or null if there are no commonalities. For example, if the list contains
* <i>foobar</i>, <i>foobaz</i>, <i>foobuz</i>, the method will return <i>foob</i>.
*/
private String getUnambiguousCompletions(final List<CharSequence> candidates) {
if (candidates == null || candidates.isEmpty()) {
return null;
}
// convert to an array for speed
String[] strings = candidates.toArray(new String[candidates.size()]);
String first = strings[0];
StringBuilder candidate = new StringBuilder();
for (int i = 0; i < first.length(); i++) {
if (startsWith(first.substring(0, i + 1), strings)) {
candidate.append(first.charAt(i));
}
else {
break;
}
}
return candidate.toString();
}
/**
* @return true is all the elements of <i>candidates</i> start with <i>starts</i>
*/
private boolean startsWith(final String starts, final String[] candidates) {
for (String candidate : candidates) {
if (!candidate.startsWith(starts)) {
return false;
}
}
return true;
}
private static enum Messages
{
DISPLAY_CANDIDATES,
DISPLAY_CANDIDATES_YES,
DISPLAY_CANDIDATES_NO,;
private static final
ResourceBundle
bundle =
ResourceBundle.getBundle(CandidateListCompletionHandler.class.getName(), Locale.getDefault());
public String format(final Object... args) {
if (bundle == null)
return "";
else
return String.format(bundle.getString(name()), args);
}
}
}