com.google.errorprone.bugpatterns.NullableVoid Maven / Gradle / Ivy
/*
* Copyright 2015 The Error Prone 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 com.google.errorprone.bugpatterns;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import com.google.errorprone.BugPattern;
import com.google.errorprone.BugPattern.StandardTags;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.AnnotationTree;
import com.sun.source.tree.MethodTree;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
import javax.lang.model.type.TypeKind;
/** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
@BugPattern(
summary =
"void-returning methods should not be annotated with @Nullable,"
+ " since they cannot return null",
severity = WARNING,
tags = StandardTags.STYLE)
public class NullableVoid extends BugChecker implements MethodTreeMatcher {
@Override
public Description matchMethod(MethodTree tree, VisitorState state) {
MethodSymbol sym = ASTHelpers.getSymbol(tree);
if (sym.getReturnType().getKind() != TypeKind.VOID) {
return NO_MATCH;
}
AnnotationTree annotation =
ASTHelpers.getAnnotationWithSimpleName(tree.getModifiers().getAnnotations(), "Nullable");
if (annotation == null) {
return NO_MATCH;
}
return describeMatch(annotation, SuggestedFix.delete(annotation));
}
}