io.micronaut.cli.interactive.completers.SortedAggregateCompleter Maven / Gradle / Ivy

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/*
 * Copyright 2017-2020 original authors
 *
 * 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 io.micronaut.cli.interactive.completers;

import static jline.internal.Preconditions.checkNotNull;

import jline.console.completer.Completer;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.SortedSet;
import java.util.TreeSet;

/**
 * Copied from jline AggregateCompleter.
 * 
 * Sorts aggregated completions.
 *
 * @since 1.0
 */
public class SortedAggregateCompleter implements Completer {
    private final List completers = new ArrayList();

    /**
     * Default constructor.
     */
    public SortedAggregateCompleter() {
        // empty
    }

    /**
     * Construct an AggregateCompleter with the given collection of completers.
     * The completers will be used in the iteration order of the collection.
     *
     * @param completers the collection of completers
     */
    public SortedAggregateCompleter(final Collection completers) {
        checkNotNull(completers);
        this.completers.addAll(completers);
    }

    /**
     * Construct an AggregateCompleter with the given completers.
     * The completers will be used in the order given.
     *
     * @param completers the completers
     */
    public SortedAggregateCompleter(final Completer... completers) {
        this(Arrays.asList(completers));
    }

    /**
     * Retrieve the collection of completers currently being aggregated.
     *
     * @return the aggregated completers
     */
    public Collection getCompleters() {
        return completers;
    }

    @Override
    public int complete(final String buffer, final int cursor, final List candidates) {
        // buffer could be null
        checkNotNull(candidates);

        List completions = new ArrayList(completers.size());

        // Run each completer, saving its completion results
        int max = -1;
        for (Completer completer : completers) {
            Completion completion = new Completion(candidates);
            completion.complete(completer, buffer, cursor);

            // Compute the max cursor position
            max = Math.max(max, completion.cursor);

            completions.add(completion);
        }

        SortedSet allCandidates = new TreeSet<>();

        // Append candidates from completions which have the same cursor position as max
        for (Completion completion : completions) {
            if (completion.cursor == max) {
                allCandidates.addAll(completion.candidates);
            }
        }

        candidates.addAll(allCandidates);

        return max;
    }

    /**
     * @return a string representing the aggregated completers
     */
    @Override
    public String toString() {
        return getClass().getSimpleName() + "{" +
            "completers=" + completers +
            '}';
    }

    /**
     * Completion.
     */
    private class Completion {
        final List candidates;

        int cursor;

        public Completion(final List candidates) {
            checkNotNull(candidates);
            this.candidates = new LinkedList(candidates);
        }

        public void complete(final Completer completer, final String buffer, final int cursor) {
            checkNotNull(completer);
            this.cursor = completer.complete(buffer, cursor, candidates);
        }
    }
}