Java tutorial
/* * Copyright 2018 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.time; import static com.google.errorprone.BugPattern.ProvidesFix.REQUIRES_HUMAN_ATTENTION; import static com.google.errorprone.BugPattern.SeverityLevel.WARNING; import static com.google.errorprone.matchers.Matchers.allOf; import static com.google.errorprone.matchers.Matchers.anyOf; import static com.google.errorprone.matchers.Matchers.not; import static com.google.errorprone.matchers.Matchers.packageStartsWith; import com.google.common.collect.Iterables; import com.google.errorprone.BugPattern; import com.google.errorprone.VisitorState; import com.google.errorprone.bugpatterns.BugChecker; import com.google.errorprone.bugpatterns.BugChecker.NewClassTreeMatcher; import com.google.errorprone.fixes.SuggestedFix; import com.google.errorprone.matchers.Description; import com.google.errorprone.matchers.Matcher; import com.google.errorprone.matchers.Matchers; import com.sun.source.tree.ExpressionTree; import com.sun.source.tree.NewClassTree; import com.sun.tools.javac.tree.JCTree; /** Check for calls to new Duration(long). */ @BugPattern(name = "JodaDurationConstructor", summary = "Use of new Duration(long) is not allowed. Please use Duration.millis(long) instead.", explanation = "Joda-Time's 'new Duration(long)' constructor is ambiguous with respect to time units and " + "is frequently a source of bugs. Please use Duration.millis(long) instead. If your " + "Duration is better expressed in terms of other units, use standardSeconds(long), " + "standardMinutes(long), standardHours(long), or standardDays(long) instead.", severity = WARNING, providesFix = REQUIRES_HUMAN_ATTENTION) public final class JodaDurationConstructor extends BugChecker implements NewClassTreeMatcher { private static final Matcher<ExpressionTree> MATCHER = allOf( anyOf(Matchers.constructor().forClass("org.joda.time.Duration").withParameters("int"), Matchers.constructor().forClass("org.joda.time.Duration").withParameters("long")), // Allow usage by JodaTime itself not(packageStartsWith("org.joda.time"))); @Override public Description matchNewClass(NewClassTree tree, VisitorState state) { if (!MATCHER.matches(tree, state)) { return Description.NO_MATCH; } ExpressionTree millisArg = Iterables.getOnlyElement(tree.getArguments()); SuggestedFix fix = SuggestedFix.replace(((JCTree) tree).getStartPosition(), ((JCTree) millisArg).getStartPosition(), state.getSourceForNode(tree.getIdentifier()) + ".millis("); return describeMatch(tree, fix); } }