com.google.errorprone.bugpatterns.ArrayEquals Maven / Gradle / Ivy
/*
* Copyright 2012 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.ERROR;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.matchers.Matchers.allOf;
import static com.google.errorprone.matchers.Matchers.argument;
import static com.google.errorprone.matchers.Matchers.instanceMethod;
import static com.google.errorprone.matchers.Matchers.isArrayType;
import static com.google.errorprone.matchers.Matchers.staticEqualsInvocation;
import static com.google.errorprone.predicates.TypePredicates.isArray;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
import com.google.errorprone.fixes.Fix;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
/**
* @author [email protected] (Eddie Aftandilian)
*/
@BugPattern(summary = "Reference equality used to compare arrays", severity = ERROR)
public class ArrayEquals extends BugChecker implements MethodInvocationTreeMatcher {
/** Matches when the equals instance method is used to compare two arrays. */
private static final Matcher instanceEqualsMatcher =
allOf(instanceMethod().onClass(isArray()).named("equals"), argument(0, isArrayType()));
/** Matches when {@link java.util.Objects#equals}-like methods compare two arrays. */
private static final Matcher staticEqualsMatcher =
allOf(staticEqualsInvocation(), argument(0, isArrayType()), argument(1, isArrayType()));
/**
* Suggests replacing with Arrays.equals(a, b). Also adds the necessary import statement for
* java.util.Arrays.
*/
@Override
public Description matchMethodInvocation(MethodInvocationTree t, VisitorState state) {
String arg1;
String arg2;
if (instanceEqualsMatcher.matches(t, state)) {
arg1 = state.getSourceForNode(((JCFieldAccess) t.getMethodSelect()).getExpression());
arg2 = state.getSourceForNode(t.getArguments().get(0));
} else if (staticEqualsMatcher.matches(t, state)) {
arg1 = state.getSourceForNode(t.getArguments().get(0));
arg2 = state.getSourceForNode(t.getArguments().get(1));
} else {
return NO_MATCH;
}
Fix fix =
SuggestedFix.builder()
.replace(t, "Arrays.equals(" + arg1 + ", " + arg2 + ")")
.addImport("java.util.Arrays")
.build();
return describeMatch(t, fix);
}
}