/*
* Copyright 2011 SpringSource
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.grails.build.interactive;
import jline.console.ConsoleReader;
import jline.console.CursorBuffer;
import jline.console.completer.CompletionHandler;
import java.io.IOException;
import java.util.List;
/**
* Fixes issues with the default CandidateListCompletionHandler such as clearing out the whole buffer when
* a completion matches a list of candidates
*
* @author Graeme Rocher
* @since 2.0
*/
public class CandidateListCompletionHandler implements CompletionHandler {
private boolean eagerNewlines = true;
public void setAlwaysIncludeNewline(boolean eagerNewlines) {
this.eagerNewlines = eagerNewlines;
}
public boolean complete(ConsoleReader reader, @SuppressWarnings("rawtypes") List<CharSequence> candidates, int pos) throws IOException {
CursorBuffer buf = reader.getCursorBuffer();
// if there is only one completion, then fill in the buffer
if (candidates.size() == 1) {
String value = candidates.get(0).toString();
// fail if the only candidate is the same as the current buffer
if (value.equals(buf.toString())) {
return false;
}
jline.console.completer.CandidateListCompletionHandler.setBuffer(reader, value, pos);
return true;
}
if (candidates.size() > 1) {
String value = getUnambiguousCompletions(candidates);
jline.console.completer.CandidateListCompletionHandler.setBuffer(reader, value, pos);
}
if (eagerNewlines) {
reader.println();
}
jline.console.completer.CandidateListCompletionHandler.printCandidates(reader, candidates);
// redraw the current console buffer
reader.drawLine();
return true;
}
/**
* Returns a root that matches all the {@link String} elements
* of the specified {@link List}, or null if there are
* no commalities. For example, if the list contains
* <i>foobar</i>, <i>foobaz</i>, <i>foobuz</i>, the
* method will return <i>foob</i>.
*/
private final String getUnambiguousCompletions(final List<?> 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, count = first.length(); i < count; 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 final boolean startsWith(final String starts, final String[] candidates) {
for (int i = 0; i < candidates.length; i++) {
if (!candidates[i].startsWith(starts)) {
return false;
}
}
return true;
}
}