/*
* 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.unused;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import java.util.Collection;
import java.util.List;
import org.apache.commons.lang.BooleanUtils;
import org.sonar.check.Rule;
import org.sonar.java.matcher.MethodMatcher;
import org.sonar.java.matcher.MethodMatcherCollection;
import org.sonar.java.model.ModifiersUtils;
import org.sonar.java.model.declaration.MethodTreeImpl;
import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
import org.sonar.plugins.java.api.JavaFileScannerContext;
import org.sonar.plugins.java.api.semantic.Symbol;
import org.sonar.plugins.java.api.semantic.Type;
import org.sonar.plugins.java.api.tree.AnnotationTree;
import org.sonar.plugins.java.api.tree.BlockTree;
import org.sonar.plugins.java.api.tree.IdentifierTree;
import org.sonar.plugins.java.api.tree.LiteralTree;
import org.sonar.plugins.java.api.tree.MethodTree;
import org.sonar.plugins.java.api.tree.Modifier;
import org.sonar.plugins.java.api.tree.ModifiersTree;
import org.sonar.plugins.java.api.tree.NewArrayTree;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.VariableTree;
import java.util.ArrayList;
@Rule(key = "S1172")
public class UnusedMethodParameterCheck extends IssuableSubscriptionVisitor {
private static final String AUTHORIZED_ANNOTATION = "javax.enterprise.event.Observes";
private static final String SUPPRESS_WARNINGS_ANNOTATION = "java.lang.SuppressWarnings";
private static final Collection<String> EXCLUDED_WARNINGS_SUPPRESSIONS = ImmutableList.of("\"rawtypes\"", "\"unchecked\"");
private static final MethodMatcherCollection SERIALIZABLE_METHODS = MethodMatcherCollection.create(
MethodMatcher.create().name("writeObject").addParameter("java.io.ObjectOutputStream"),
MethodMatcher.create().name("readObject").addParameter("java.io.ObjectInputStream"));
private static final String STRUTS_ACTION_SUPERCLASS = "org.apache.struts.action.Action";
private static final Collection<String> EXCLUDED_STRUTS_ACTION_PARAMETER_TYPES = ImmutableList.of("org.apache.struts.action.ActionMapping",
"org.apache.struts.action.ActionForm", "javax.servlet.http.HttpServletRequest", "javax.servlet.http.HttpServletResponse");
@Override
public List<Tree.Kind> nodesToVisit() {
return ImmutableList.of(Tree.Kind.METHOD, Tree.Kind.CONSTRUCTOR);
}
@Override
public void visitNode(Tree tree) {
MethodTree methodTree = (MethodTree) tree;
if (hasSemantic() && methodTree.block() != null && !isExcluded(methodTree)) {
List<IdentifierTree> unused = Lists.newArrayList();
for (VariableTree var : methodTree.parameters()) {
Symbol symbol = var.symbol();
if (symbol.usages().isEmpty() && !symbol.metadata().isAnnotatedWith(AUTHORIZED_ANNOTATION) && !isStrutsActionParameter(var)) {
unused.add(var.simpleName());
}
}
if (!unused.isEmpty()) {
List<JavaFileScannerContext.Location> locations = new ArrayList<>();
for (IdentifierTree identifier : unused.subList(1, unused.size())) {
locations.add(new JavaFileScannerContext.Location("Remove this unused method parameter "+identifier.name()+"\".", identifier));
}
IdentifierTree firstUnused = unused.get(0);
reportIssue(firstUnused, "Remove this unused method parameter \"" + firstUnused.name() + "\".", locations, null);
}
}
}
private static boolean isExcluded(MethodTree tree) {
return ((MethodTreeImpl) tree).isMainMethod()
|| isAnnotated(tree)
|| isOverriding(tree)
|| isSerializableMethod(tree)
|| isDesignedForExtension(tree);
}
private static boolean isAnnotated(MethodTree tree) {
// If any annotation doesn't match the @SuppressWarning then mark the method as annotated.
return tree.modifiers().annotations().stream().anyMatch(annotation -> !isExcludedLiteral(annotation));
}
private static boolean isExcludedLiteral(Tree tree) {
if (tree.is(Tree.Kind.ANNOTATION)) {
AnnotationTree annotationTree = (AnnotationTree) tree;
return annotationTree.annotationType().symbolType().is(SUPPRESS_WARNINGS_ANNOTATION)
&& annotationTree.arguments().stream().allMatch(UnusedMethodParameterCheck::isExcludedLiteral);
} else if (tree.is(Tree.Kind.STRING_LITERAL)) {
return EXCLUDED_WARNINGS_SUPPRESSIONS.contains(((LiteralTree) tree).value());
} else if (tree.is(Tree.Kind.NEW_ARRAY)) {
return ((NewArrayTree) tree).initializers().stream().allMatch(UnusedMethodParameterCheck::isExcludedLiteral);
}
// If it is some type we don't expect, then return false to avoid FP.
return false;
}
private static boolean isDesignedForExtension(MethodTree tree) {
ModifiersTree modifiers = tree.modifiers();
return ModifiersUtils.hasModifier(modifiers, Modifier.DEFAULT)
|| (!ModifiersUtils.hasModifier(modifiers, Modifier.PRIVATE) && isEmptyOrThrowStatement(tree.block()));
}
private static boolean isStrutsActionParameter(VariableTree variableTree) {
Type superClass = variableTree.symbol().enclosingClass().superClass();
return superClass != null && superClass.isSubtypeOf(STRUTS_ACTION_SUPERCLASS)
&& EXCLUDED_STRUTS_ACTION_PARAMETER_TYPES.contains(variableTree.symbol().type().fullyQualifiedName());
}
private static boolean isEmptyOrThrowStatement(BlockTree block) {
return block.body().isEmpty() || (block.body().size() == 1 && block.body().get(0).is(Tree.Kind.THROW_STATEMENT));
}
private static boolean isSerializableMethod(MethodTree methodTree) {
return ModifiersUtils.hasModifier(methodTree.modifiers(), Modifier.PRIVATE) && SERIALIZABLE_METHODS.anyMatch(methodTree);
}
private static boolean isOverriding(MethodTree tree) {
// if overriding cannot be determined, we consider it is overriding to avoid FP.
return !BooleanUtils.isFalse(((MethodTreeImpl) tree).isOverriding());
}
}