org.sonar.java.checks.RedundantAbstractMethodCheck.java Source code

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Here is the source code for org.sonar.java.checks.RedundantAbstractMethodCheck.java

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/*
 * SonarQube Java
 * Copyright (C) 2012-2016 SonarSource SA
 * mailto:contact AT sonarsource DOT com
 *
 * 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  02110-1301, USA.
 */
package org.sonar.java.checks;

import com.google.common.collect.ImmutableList;
import org.apache.commons.collections.CollectionUtils;
import org.sonar.check.Rule;
import org.sonar.java.resolve.JavaSymbol;
import org.sonar.java.resolve.JavaType;
import org.sonar.java.resolve.MethodJavaType;
import org.sonar.java.resolve.ParametrizedTypeJavaType;
import org.sonar.java.resolve.SymbolMetadataResolve;
import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
import org.sonar.plugins.java.api.semantic.Symbol;
import org.sonar.plugins.java.api.semantic.SymbolMetadata.AnnotationInstance;
import org.sonar.plugins.java.api.semantic.Type;
import org.sonar.plugins.java.api.tree.MethodTree;
import org.sonar.plugins.java.api.tree.Tree;

import java.util.List;

@Rule(key = "S3038")
public class RedundantAbstractMethodCheck extends IssuableSubscriptionVisitor {

    @Override
    public List<Tree.Kind> nodesToVisit() {
        return ImmutableList.of(Tree.Kind.METHOD);
    }

    @Override
    public void visitNode(Tree tree) {
        if (!hasSemantic()) {
            return;
        }
        Symbol.MethodSymbol method = ((MethodTree) tree).symbol();
        if (method.isAbstract() && method.owner().isAbstract()) {
            checkMethod((JavaSymbol.MethodJavaSymbol) method);
        }
    }

    private void checkMethod(JavaSymbol.MethodJavaSymbol method) {
        JavaSymbol.MethodJavaSymbol overridee = method.overriddenSymbol();
        if (overridee != null && overridee.owner().isInterface() && !differentContract(method, overridee)) {
            reportIssue(method.declaration(), "\"" + method.name() + "\" is defined in the \""
                    + overridee.owner().name() + "\" interface and can be removed from this class.");
        }
    }

    private static boolean differentContract(JavaSymbol.MethodJavaSymbol method,
            JavaSymbol.MethodJavaSymbol overridee) {
        return removingParametrizedAspect(method, overridee) || differentThrows(method, overridee)
                || differentReturnType(method, overridee) || differentParameters(method, overridee)
                || differentAnnotations(method.metadata(), overridee.metadata());
    }

    private static boolean removingParametrizedAspect(JavaSymbol.MethodJavaSymbol method,
            JavaSymbol.MethodJavaSymbol overridee) {
        return !method.isParametrized() && overridee.isParametrized();
    }

    private static boolean differentThrows(JavaSymbol.MethodJavaSymbol method,
            JavaSymbol.MethodJavaSymbol overridee) {
        return !CollectionUtils.isEqualCollection(method.thrownTypes(), overridee.thrownTypes());
    }

    private static boolean differentReturnType(JavaSymbol.MethodJavaSymbol method,
            JavaSymbol.MethodJavaSymbol overridee) {
        JavaType methodResultType = resultType(method);
        JavaType overrideeResultType = resultType(overridee);
        return specializationOfReturnType(methodResultType.erasure(), overrideeResultType.erasure())
                || useRawTypeOfParametrizedType(methodResultType, overrideeResultType);
    }

    private static JavaType resultType(JavaSymbol.MethodJavaSymbol method) {
        return ((MethodJavaType) method.type()).resultType();
    }

    private static boolean specializationOfReturnType(JavaType methodResultType, JavaType overrideeResultType) {
        return !methodResultType.isVoid() && (methodResultType.isSubtypeOf(overrideeResultType)
                && !overrideeResultType.isSubtypeOf(methodResultType));
    }

    private static boolean differentParameters(JavaSymbol.MethodJavaSymbol method,
            JavaSymbol.MethodJavaSymbol overridee) {
        return useRawTypeOfParametrizedType(method.parameterTypes(), overridee.parameterTypes())
                || differentAnnotations(method.getParameters().scopeSymbols(),
                        overridee.getParameters().scopeSymbols());
    }

    private static boolean useRawTypeOfParametrizedType(List<Type> methodParamTypes,
            List<Type> overrideeParamType) {
        for (int i = 0; i < methodParamTypes.size(); i++) {
            if (useRawTypeOfParametrizedType(methodParamTypes.get(i), overrideeParamType.get(i))) {
                return true;
            }
        }
        return false;
    }

    private static boolean useRawTypeOfParametrizedType(Type methodParam, Type overrideeParam) {
        return overrideeParam instanceof ParametrizedTypeJavaType && methodParam.equals(overrideeParam.erasure());
    }

    private static boolean differentAnnotations(List<JavaSymbol> methodParamSymbols,
            List<JavaSymbol> overrideeParamSymbols) {
        for (int i = 0; i < methodParamSymbols.size(); i++) {
            if (differentAnnotations(methodParamSymbols.get(i).metadata(),
                    overrideeParamSymbols.get(i).metadata())) {
                return true;
            }
        }
        return false;
    }

    private static boolean differentAnnotations(SymbolMetadataResolve methodMetadata,
            SymbolMetadataResolve overrideeMetadata) {
        for (AnnotationInstance annotation : methodMetadata.annotations()) {
            Type type = annotation.symbol().type();
            if (!type.is("java.lang.Override") && !overrideeMetadata.isAnnotatedWith(type.fullyQualifiedName())) {
                return true;
            }
        }
        return false;
    }
}