1// Copyright 2014 The Bazel Authors. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//    http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14package com.google.devtools.common.options;
15
16import javax.annotation.Nullable;
17
18/**
19 * A read-only interface for options parser results, which only allows to query the options of
20 * a specific class, but not e.g. the residue any other information pertaining to the command line.
21 */
22public interface OptionsClassProvider {
23  public static final OptionsClassProvider EMPTY = new OptionsClassProvider() {
24    @Override @Nullable
25    public <O extends OptionsBase> O getOptions(Class<O> optionsClass) {
26      return null;
27    }
28  };
29
30  /**
31   * Returns the options instance for the given {@code optionsClass}, that is,
32   * the parsed options, or null if it is not among those available.
33   *
34   * <p>The returned options should be treated by library code as immutable and
35   * a provider is permitted to return the same options instance multiple times.
36   */
37  @Nullable <O extends OptionsBase> O getOptions(Class<O> optionsClass);
38}
39