org.sonar.java.checks.ClassWithOnlyStaticMethodsInstantiationCheck Maven / Gradle / Ivy
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/*
* SonarQube Java
* Copyright (C) 2012 SonarSource
* [email protected]
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02
*/
package org.sonar.java.checks;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import org.sonar.api.server.rule.RulesDefinition;
import org.sonar.check.Priority;
import org.sonar.check.Rule;
import org.sonar.plugins.java.api.semantic.Symbol;
import org.sonar.plugins.java.api.semantic.Symbol.MethodSymbol;
import org.sonar.plugins.java.api.semantic.Type;
import org.sonar.plugins.java.api.tree.IdentifierTree;
import org.sonar.plugins.java.api.tree.MemberSelectExpressionTree;
import org.sonar.plugins.java.api.tree.NewClassTree;
import org.sonar.plugins.java.api.tree.ParameterizedTypeTree;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.Tree.Kind;
import org.sonar.plugins.java.api.tree.TypeTree;
import org.sonar.squidbridge.annotations.ActivatedByDefault;
import org.sonar.squidbridge.annotations.SqaleConstantRemediation;
import org.sonar.squidbridge.annotations.SqaleSubCharacteristic;
import javax.annotation.Nullable;
import java.text.MessageFormat;
import java.util.Collection;
import java.util.List;
@Rule(
key = "S2440",
name = "Classes with only \"static\" methods should not be instantiated",
priority = Priority.MAJOR,
tags = {"clumsy"})
@ActivatedByDefault
@SqaleSubCharacteristic(RulesDefinition.SubCharacteristics.UNDERSTANDABILITY)
@SqaleConstantRemediation("2min")
public class ClassWithOnlyStaticMethodsInstantiationCheck extends SubscriptionBaseVisitor {
@Override
public List nodesToVisit() {
return ImmutableList.of(Kind.NEW_CLASS);
}
@Override
public void visitNode(Tree tree) {
TypeTree identifier = ((NewClassTree) tree).identifier();
Symbol.TypeSymbol newClassTypeSymbol = identifier.symbolType().symbol();
if (!newClassTypeSymbol.isEnum() && hasOnlyStaticMethods(newClassTypeSymbol) && !instantiateOwnClass(identifier, newClassTypeSymbol)) {
String message = "Remove this instantiation.";
String name = getNewClassName(identifier);
if (name != null) {
message = "Remove this instantiation of \"{0}\".";
}
addIssue(tree, MessageFormat.format(message, name));
}
}
private boolean instantiateOwnClass(Tree identifier, Symbol.TypeSymbol newClassTypeSymbol) {
Type enclosingClassType = getSemanticModel().getEnclosingClass(identifier).type();
return enclosingClassType.equals(newClassTypeSymbol.type());
}
private boolean hasOnlyStaticMethods(Symbol.TypeSymbol newClassTypeSymbol) {
Collection methods = filterMethods(newClassTypeSymbol.memberSymbols());
if (methods.isEmpty()) {
return false;
}
for (MethodSymbol method : methods) {
if (!method.isStatic()) {
return false;
}
}
return superClassHasOnlyStaticMethods(newClassTypeSymbol);
}
private boolean superClassHasOnlyStaticMethods(Symbol.TypeSymbol newClassTypeSymbol) {
Type superClass = newClassTypeSymbol.superClass();
if (superClass != null && !superClass.is("java.lang.Object")) {
return hasOnlyStaticMethods(superClass.symbol());
}
return true;
}
private Collection filterMethods(Collection symbols) {
List methods = Lists.newArrayList();
for (Symbol symbol : symbols) {
if (symbol.isMethodSymbol() && !isConstructor(symbol)) {
methods.add((MethodSymbol) symbol);
}
}
return methods;
}
private boolean isConstructor(Symbol symbol) {
return "".equals(symbol.name());
}
@Nullable
private String getNewClassName(Tree tree) {
if (tree.is(Kind.IDENTIFIER)) {
return ((IdentifierTree) tree).name();
} else if (tree.is(Kind.MEMBER_SELECT)) {
return ((MemberSelectExpressionTree) tree).identifier().name();
} else if (tree.is(Kind.PARAMETERIZED_TYPE)) {
return getNewClassName(((ParameterizedTypeTree) tree).type());
}
return null;
}
}
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