com.google.errorprone.bugpatterns.MultipleParallelOrSequentialCalls Maven / Gradle / Ivy
/*
* 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.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Matchers.instanceMethod;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.MemberSelectTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.util.TreePath;
/** @author [email protected] (Maria Sam) */
@BugPattern(
name = "MultipleParallelOrSequentialCalls",
summary =
"Multiple calls to either parallel or sequential are unnecessary and cause confusion.",
severity = WARNING)
public class MultipleParallelOrSequentialCalls extends BugChecker
implements MethodInvocationTreeMatcher {
private static final Matcher STREAM =
instanceMethod().onDescendantOf("java.util.Collection").named("stream");
private static final Matcher PARALLELSTREAM =
instanceMethod().onDescendantOf("java.util.Collection").named("parallelStream");
@Override
public Description matchMethodInvocation(MethodInvocationTree t, VisitorState state) {
if (STREAM.matches(t, state) || PARALLELSTREAM.matches(t, state)) {
int appropriateAmount = STREAM.matches(t, state) ? 1 : 0;
SuggestedFix.Builder builder = SuggestedFix.builder();
TreePath pathToMet =
ASTHelpers.findPathFromEnclosingNodeToTopLevel(
state.getPath(), MethodInvocationTree.class);
// counts how many instances of parallel / sequential
int count = 0;
String toReplace = "empty";
while (pathToMet != null) {
MethodInvocationTree methodInvocationTree = (MethodInvocationTree) pathToMet.getLeaf();
// this check makes it so that we stop iterating up once it's done
if (methodInvocationTree.getArguments().stream()
.map(m -> state.getSourceForNode(m))
.anyMatch(m -> m.contains(state.getSourceForNode(t)))) {
break;
}
if (methodInvocationTree.getMethodSelect() instanceof MemberSelectTree) {
MemberSelectTree memberSelectTree =
(MemberSelectTree) methodInvocationTree.getMethodSelect();
String memberSelectIdentifier = memberSelectTree.getIdentifier().toString();
// checks for the first instance of parallel / sequential
if (toReplace.equals("empty")
&& (memberSelectIdentifier.equals("parallel")
|| memberSelectIdentifier.equals("sequential"))) {
toReplace = memberSelectIdentifier.equals("parallel") ? "parallel" : "sequential";
}
// immediately removes any instances of the appropriate string
if (memberSelectIdentifier.equals(toReplace)) {
int endOfExpression = state.getEndPosition(memberSelectTree.getExpression());
builder.replace(endOfExpression, state.getEndPosition(methodInvocationTree), "");
count++;
}
}
pathToMet =
ASTHelpers.findPathFromEnclosingNodeToTopLevel(pathToMet, MethodInvocationTree.class);
}
// if there are too many parallel / sequential calls, then we describe match and actually
// use the builder's replacements and add a postfix
if (count > appropriateAmount) {
// parallel stream doesn't need a postfix
if (appropriateAmount == 1) {
builder.postfixWith(t, "." + toReplace + "()");
}
return describeMatch(t, builder.build());
}
}
return Description.NO_MATCH;
}
}