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

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

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/*
 * Copyright 2017 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.common.collect.Iterables.getLast;
import static com.google.common.collect.Streams.forEachPair;
import static com.google.errorprone.BugPattern.Category.JDK;
import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
import static com.google.errorprone.matchers.Description.NO_MATCH;

import com.google.common.collect.ImmutableList;
import com.google.errorprone.BugPattern;
import com.google.errorprone.BugPattern.ProvidesFix;
import com.google.errorprone.BugPattern.StandardTags;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
import com.google.errorprone.bugpatterns.BugChecker.NewClassTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.google.errorprone.util.Commented;
import com.google.errorprone.util.Comments;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.NewClassTree;
import com.sun.source.tree.Tree;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
import com.sun.tools.javac.code.Symbol.VarSymbol;
import com.sun.tools.javac.parser.Tokens.Comment;
import java.util.stream.Stream;

/** @author cushon@google.com (Liam Miller-Cushon) */
@BugPattern(name = "ParameterComment", category = JDK, summary = "Non-standard parameter comment; prefer `/* paramName= */ arg`", severity = SUGGESTION, tags = StandardTags.STYLE, providesFix = ProvidesFix.REQUIRES_HUMAN_ATTENTION)
public class ParameterComment extends BugChecker implements MethodInvocationTreeMatcher, NewClassTreeMatcher {

    @Override
    public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
        return matchNewClassOrMethodInvocation(ASTHelpers.getSymbol(tree),
                Comments.findCommentsForArguments(tree, state), tree);
    }

    @Override
    public Description matchNewClass(NewClassTree tree, VisitorState state) {
        return matchNewClassOrMethodInvocation(ASTHelpers.getSymbol(tree),
                Comments.findCommentsForArguments(tree, state), tree);
    }

    private Description matchNewClassOrMethodInvocation(MethodSymbol symbol,
            ImmutableList<Commented<ExpressionTree>> arguments, Tree tree) {
        if (symbol.getParameters().isEmpty()) {
            return NO_MATCH;
        }
        SuggestedFix.Builder fix = SuggestedFix.builder();
        forEachPair(arguments.stream(), Stream.concat(symbol.getParameters().stream(),
                Stream.iterate(getLast(symbol.getParameters()), x -> x)), (commented, param) -> {
                    ImmutableList<Comment> comments = commented.afterComments().isEmpty()
                            ? commented.beforeComments()
                            : commented.afterComments();
                    boolean matchStandardForm = !commented.afterComments().isEmpty();
                    comments.stream().filter(c -> matchingParamComment(c, param, matchStandardForm)).findFirst()
                            .ifPresent(c -> fixParamComment(fix, commented, param, c));
                });
        return fix.isEmpty() ? NO_MATCH : describeMatch(tree, fix.build());
    }

    private static boolean matchingParamComment(Comment c, VarSymbol param, boolean matchStandardForm) {
        String text = Comments.getTextFromComment(c).trim();
        if (text.endsWith("=")) {
            if (!matchStandardForm) {
                return false;
            }
            text = text.substring(0, text.length() - "=".length()).trim();
        }
        return param.getSimpleName().contentEquals(text);
    }

    private static void fixParamComment(SuggestedFix.Builder fix, Commented<ExpressionTree> commented,
            VarSymbol param, Comment c) {
        fix.prefixWith(commented.tree(), String.format("/* %s= */ ", param.getSimpleName()))
                .replace(c.getSourcePos(0), c.getSourcePos(0) + c.getText().length(), "");
    }
}