com.google.errorprone.bugpatterns.ConstantField Maven / Gradle / Ivy
/*
* Copyright 2016 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.SUGGESTION;
import com.google.common.base.Ascii;
import com.google.common.base.CaseFormat;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.VariableTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.fixes.SuggestedFixes;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.VariableTree;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.code.Symbol.VarSymbol;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.Modifier;
/** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
@BugPattern(
name = "ConstantField",
summary = "Fields with CONSTANT_CASE names should be both static and final",
severity = SUGGESTION,
tags = BugPattern.StandardTags.STYLE)
public class ConstantField extends BugChecker implements VariableTreeMatcher {
@Override
public Description matchVariable(VariableTree tree, VisitorState state) {
Symbol.VarSymbol sym = ASTHelpers.getSymbol(tree);
if (sym == null || sym.getKind() != ElementKind.FIELD) {
return Description.NO_MATCH;
}
String name = sym.getSimpleName().toString();
if (sym.isStatic() && sym.getModifiers().contains(Modifier.FINAL)) {
return Description.NO_MATCH;
}
if (!name.equals(Ascii.toUpperCase(name))) {
return Description.NO_MATCH;
}
Description.Builder descriptionBuilder = buildDescription(tree);
if (canBecomeStaticMember(sym)) {
SuggestedFixes.addModifiers(tree, state, Modifier.FINAL, Modifier.STATIC)
.map(
f ->
SuggestedFix.builder()
.setShortDescription("make static and final")
.merge(f)
.build())
.ifPresent(descriptionBuilder::addFix);
}
return descriptionBuilder
.addFix(
SuggestedFix.builder()
.setShortDescription("change to camelcase")
.merge(
SuggestedFixes.renameVariable(
tree, CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_CAMEL, name), state))
.build())
.build();
}
private static boolean canBecomeStaticMember(VarSymbol sym) {
// JLS 8.1.3: It is a compile-time error if an inner class declares a member that is
// explicitly or implicitly static, unless the member is a constant variable (§4.12.4).
// We could try and figure out if the declaration *would* be a compile time constant if made
// static, but that's a bit much to keep adding this fix.
ClassSymbol owningClass = sym.enclClass();
// Enum anonymous classes aren't considered isInner() even though they can't hold static fields
switch (owningClass.getNestingKind()) {
case LOCAL:
case ANONYMOUS:
return false;
default:
return !owningClass.isInner();
}
}
}