java/src/com/google/idea/blaze/java/projectview/JavaLanguageLevelSection.java

/*
 * Copyright 2016 The Bazel Authors. All rights reserved.
 *
 * 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 com.google.idea.blaze.java.projectview;

import com.google.idea.blaze.base.projectview.ProjectViewSet;
import com.google.idea.blaze.base.projectview.parser.ParseContext;
import com.google.idea.blaze.base.projectview.parser.ProjectViewParser;
import com.google.idea.blaze.base.projectview.section.ScalarSection;
import com.google.idea.blaze.base.projectview.section.ScalarSectionParser;
import com.google.idea.blaze.base.projectview.section.SectionKey;
import com.google.idea.blaze.base.projectview.section.SectionParser;
import com.intellij.pom.java.LanguageLevel;
import javax.annotation.Nullable;

/** Section to force the java language level used */
public class JavaLanguageLevelSection {
  public static final SectionKey<Integer, ScalarSection<Integer>> KEY =
      SectionKey.of("java_language_level");
  public static final SectionParser PARSER = new JavaLanguageLevelParser();

  public static LanguageLevel getLanguageLevel(
      ProjectViewSet projectViewSet, LanguageLevel defaultValue) {
    return projectViewSet
        .getScalarValue(KEY)
        .map(i -> getLanguageLevel(i, defaultValue))
        .orElse(defaultValue);
  }

  @Nullable
  private static LanguageLevel getLanguageLevel(
      Integer level, @Nullable LanguageLevel defaultValue) {
    switch (level) {
      case 3:
        return LanguageLevel.JDK_1_3;
      case 4:
        return LanguageLevel.JDK_1_4;
      case 5:
        return LanguageLevel.JDK_1_5;
      case 6:
        return LanguageLevel.JDK_1_6;
      case 7:
        return LanguageLevel.JDK_1_7;
      case 8:
        return LanguageLevel.JDK_1_8;
      case 9:
        return LanguageLevel.JDK_1_9;
      default:
        return defaultValue;
    }
  }

  private static class JavaLanguageLevelParser extends ScalarSectionParser<Integer> {
    public JavaLanguageLevelParser() {
      super(KEY, ':');
    }

    @Nullable
    @Override
    protected Integer parseItem(ProjectViewParser parser, ParseContext parseContext, String rest) {
      try {
        Integer value = Integer.parseInt(rest);
        if (getLanguageLevel(value, null) != null) {
          return value;
        }
        // Fall through to error handler
      } catch (NumberFormatException e) {
        // Fall through to error handler
      }
      parseContext.addError("Illegal java language level: " + rest);
      return null;
    }

    @Override
    protected void printItem(StringBuilder sb, Integer value) {
      sb.append(value.toString());
    }

    @Override
    public ItemType getItemType() {
      return ItemType.Other;
    }
  }
}