com.palantir.baseline.errorprone.AvoidNewHashMapInt Maven / Gradle / Ivy

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A Gradle plugin for applying Baseline-recommended build and IDE settings
There is a newer version: 6.11.0
/*
 * (c) Copyright 2019 Palantir Technologies 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.palantir.baseline.errorprone;

import com.google.auto.service.AutoService;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.fixes.SuggestedFixes;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.matchers.method.MethodMatchers;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.NewClassTree;

@AutoService(BugChecker.class)
@BugPattern(
        link = "https://github.com/palantir/gradle-baseline#baseline-error-prone-checks",
        linkType = BugPattern.LinkType.CUSTOM,
        severity = BugPattern.SeverityLevel.WARNING,
        summary = "The HashMap(int) and HashSet(int) constructors are misleading: once the HashMap/HashSet reaches 3/4"
            + " of the supplied size, it resize. Instead use Maps.newHashMapWithExpectedSize or"
            + " Sets.newHashSetWithExpectedSize which behaves as expected. See"
            + " https://github.com/palantir/gradle-baseline/blob/develop/docs/best-practices/java-coding-guidelines/readme.md#avoid-new-HashMap(int)"
            + " for more information.")
public final class AvoidNewHashMapInt extends BugChecker implements BugChecker.NewClassTreeMatcher {

    private static final long serialVersionUID = 1L;

    private static final Matcher NEW_HASH_SET =
            MethodMatchers.constructor().forClass("java.util.HashSet").withParameters("int");
    private static final Matcher NEW_HASH_MAP =
            MethodMatchers.constructor().forClass("java.util.HashMap").withParameters("int");

    @Override
    public Description matchNewClass(NewClassTree tree, VisitorState state) {
        if (NEW_HASH_SET.matches(tree, state)) {
            SuggestedFix.Builder fixBuilder = SuggestedFix.builder();
            String newType = SuggestedFixes.qualifyType(state, fixBuilder, "com.google.common.collect.Sets");
            String arg = state.getSourceForNode(tree.getArguments().get(0));
            String replacement = newType + ".newHashSetWithExpectedSize(" + arg + ")";
            return buildDescription(tree)
                    .addFix(fixBuilder.replace(tree, replacement).build())
                    .build();
        }

        if (NEW_HASH_MAP.matches(tree, state)) {
            SuggestedFix.Builder fixBuilder = SuggestedFix.builder();
            String newType = SuggestedFixes.qualifyType(state, fixBuilder, "com.google.common.collect.Maps");
            String arg = state.getSourceForNode(tree.getArguments().get(0));
            String replacement = newType + ".newHashMapWithExpectedSize(" + arg + ")";
            return buildDescription(tree)
                    .addFix(fixBuilder.replace(tree, replacement).build())
                    .build();
        }

        return Description.NO_MATCH;
    }
}