com.google.errorprone.bugpatterns.ConstantField.java Source code

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Here is the source code for com.google.errorprone.bugpatterns.ConstantField.java

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/*
 * Copyright 2016 Google Inc. 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.errorprone.bugpatterns;

import static com.google.errorprone.BugPattern.Category.JDK;
import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;

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.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.Type;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.Modifier;

/** @author cushon@google.com (Liam Miller-Cushon) */
@BugPattern(name = "ConstantField", category = JDK, summary = "Field name is CONSTANT_CASE, but field is not static and final", severity = SUGGESTION)
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 checkImmutable(tree, state, sym, name);
        }
        if (!name.equals(name.toUpperCase())) {
            return Description.NO_MATCH;
        }
        return buildDescription(tree)
                .addFix(SuggestedFixes.addModifiers(tree, state, Modifier.FINAL, Modifier.STATIC))
                .addFix(SuggestedFixes.renameVariable(tree,
                        CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_CAMEL, name), state))
                .build();
    }

    private Description checkImmutable(VariableTree tree, VisitorState state, Symbol.VarSymbol sym, String name) {
        Type type = sym.type;
        if (type == null) {
            return Description.NO_MATCH;
        }
        switch (name) {
        case "serialVersionUID":
            // mandated by the Serializable API
            return Description.NO_MATCH;
        default:
            break;
        }
        if (name.toUpperCase().equals(name)) {
            return Description.NO_MATCH;
        }
        if (state.getTypes().unboxedTypeOrType(type).isPrimitive()
                || ASTHelpers.isSameType(type, state.getSymtab().stringType, state)
                || type.tsym.getKind() == ElementKind.ENUM) {
            String constName = CaseFormat.LOWER_CAMEL.to(CaseFormat.UPPER_UNDERSCORE, name);
            if (constName.startsWith("K_")) {
                constName = constName.substring("K_".length());
            }
            return buildDescription(tree)
                    .setMessage(String.format("%ss are immutable, field should be named '%s'",
                            sym.type.tsym.getSimpleName(), constName))
                    .addFix(SuggestedFixes.renameVariable(tree, constName, state)).build();
        }
        return Description.NO_MATCH;
    }
}