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.
14
15package com.google.devtools.common.options;
16
17import com.google.devtools.common.options.Converters.BooleanConverter;
18
19/**
20 * Converter that can also convert from booleans and enumerations.
21 *
22 * <p> This is able to additionally convert from the standard set of
23 * boolean string values. If there is an overlap in values, those from
24 * the underlying enumeration will be taken.
25 */
26public abstract class BoolOrEnumConverter<T extends Enum<T>> extends EnumConverter<T>{
27  private T falseValue;
28  private T trueValue;
29
30  /**
31   * You *must* implement a zero-argument constructor that delegates
32   * to this constructor, passing in the appropriate parameters. This
33   * comes from the base {@link EnumConverter} class.
34   *
35   * @param enumType The type of your enumeration; usually a class literal
36   *                 like MyEnum.class
37   * @param typeName The intuitive name of your enumeration, for example, the
38   *                 type name for CompilationMode might be "compilation mode".
39   * @param trueValue The enumeration value to associate with {@code true}.
40   * @param falseValue The enumeration value to associate with {@code false}.
41   */
42  protected BoolOrEnumConverter(Class<T> enumType, String typeName, T trueValue, T falseValue) {
43    super(enumType, typeName);
44    this.trueValue = trueValue;
45    this.falseValue = falseValue;
46  }
47
48  @Override
49  public T convert(String input) throws OptionsParsingException {
50    try {
51      return super.convert(input);
52    } catch (OptionsParsingException eEnum) {
53      try {
54        BooleanConverter booleanConverter = new BooleanConverter();
55        boolean value = booleanConverter.convert(input);
56        return value ? trueValue : falseValue;
57      } catch (OptionsParsingException eBoolean) {
58        throw eEnum;
59      }
60    }
61  }
62}
63