/*
* 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.ImmutableMap;
import org.apache.commons.lang.StringUtils;
import org.sonar.check.Rule;
import org.sonar.plugins.java.api.JavaFileScanner;
import org.sonar.plugins.java.api.JavaFileScannerContext;
import org.sonar.plugins.java.api.tree.BaseTreeVisitor;
import org.sonar.plugins.java.api.tree.BlockTree;
import org.sonar.plugins.java.api.tree.ExpressionTree;
import org.sonar.plugins.java.api.tree.IdentifierTree;
import org.sonar.plugins.java.api.tree.ReturnStatementTree;
import org.sonar.plugins.java.api.tree.StatementTree;
import org.sonar.plugins.java.api.tree.ThrowStatementTree;
import org.sonar.plugins.java.api.tree.Tree.Kind;
import org.sonar.plugins.java.api.tree.VariableTree;
import javax.annotation.CheckForNull;
import java.util.List;
import java.util.Map;
@Rule(key = "S1488")
public class ImmediatelyReturnedVariableCheck extends BaseTreeVisitor implements JavaFileScanner {
private static final Map<Kind, String> MESSAGE_KEYS = ImmutableMap.of(
Kind.THROW_STATEMENT, "throw",
Kind.RETURN_STATEMENT, "return"
);
private JavaFileScannerContext context;
private String lastTypeForMessage;
@Override
public void scanFile(JavaFileScannerContext context) {
this.context = context;
scan(context.getTree());
}
@Override
public void visitBlock(BlockTree tree) {
super.visitBlock(tree);
List<StatementTree> statements = tree.body();
int size = statements.size();
if (size < 2) {
return;
}
StatementTree butLastStatement = statements.get(size - 2);
if (butLastStatement.is(Kind.VARIABLE)) {
VariableTree variableTree = (VariableTree) butLastStatement;
if(!variableTree.modifiers().annotations().isEmpty()) {
return;
}
StatementTree lastStatement = statements.get(size - 1);
String lastStatementIdentifier = getReturnOrThrowIdentifier(lastStatement);
if (lastStatementIdentifier != null) {
String identifier = variableTree.simpleName().name();
if (StringUtils.equals(lastStatementIdentifier, identifier)) {
context.reportIssue(
this, variableTree.initializer(), "Immediately " + lastTypeForMessage + " this expression instead of assigning it to the temporary variable \"" + identifier + "\".");
}
}
}
}
@CheckForNull
private String getReturnOrThrowIdentifier(StatementTree lastStatementOfBlock) {
lastTypeForMessage = null;
ExpressionTree expr = null;
if (lastStatementOfBlock.is(Kind.THROW_STATEMENT)) {
lastTypeForMessage = MESSAGE_KEYS.get(Kind.THROW_STATEMENT);
expr = ((ThrowStatementTree) lastStatementOfBlock).expression();
} else if (lastStatementOfBlock.is(Kind.RETURN_STATEMENT)) {
lastTypeForMessage = MESSAGE_KEYS.get(Kind.RETURN_STATEMENT);
expr = ((ReturnStatementTree) lastStatementOfBlock).expression();
}
if (expr != null && expr.is(Kind.IDENTIFIER)) {
return ((IdentifierTree) expr).name();
}
return null;
}
}