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| package net.sourceforge.pmd.rules; |
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| import net.sourceforge.pmd.ast.ASTAssignmentOperator; |
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| import net.sourceforge.pmd.ast.ASTClassOrInterfaceDeclaration; |
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| import net.sourceforge.pmd.ast.ASTIfStatement; |
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| import net.sourceforge.pmd.ast.ASTLiteral; |
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| import net.sourceforge.pmd.ast.ASTMethodDeclaration; |
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| import net.sourceforge.pmd.ast.ASTName; |
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| import net.sourceforge.pmd.ast.ASTNullLiteral; |
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| import net.sourceforge.pmd.ast.ASTPrimaryExpression; |
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| import net.sourceforge.pmd.ast.ASTPrimaryPrefix; |
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| import net.sourceforge.pmd.ast.ASTReferenceType; |
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| import net.sourceforge.pmd.ast.ASTReturnStatement; |
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| import net.sourceforge.pmd.ast.ASTStatementExpression; |
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| import net.sourceforge.pmd.ast.ASTSynchronizedStatement; |
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| import net.sourceforge.pmd.ast.ASTType; |
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| import net.sourceforge.pmd.ast.Node; |
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| import java.util.ArrayList; |
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| import java.util.List; |
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| public class DoubleCheckedLocking extends net.sourceforge.pmd.AbstractRule { |
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| public Object visit(ASTClassOrInterfaceDeclaration node, Object data) {
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| if (node.isInterface()) {
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| return data;
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| } |
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| return super.visit(node, data);
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| } |
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| public Object visit(ASTMethodDeclaration node, Object data) {
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| if (node.getResultType().isVoid()) {
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| return super.visit(node, data);
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| } |
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| |
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| ASTType typeNode = (ASTType) node.getResultType().jjtGetChild(0);
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| if (typeNode.jjtGetNumChildren() == 0 || !(typeNode.jjtGetChild(0) instanceof ASTReferenceType)) {
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| return super.visit(node, data);
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| } |
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| List finder = new ArrayList();
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| node.findChildrenOfType(ASTReturnStatement.class, finder, true);
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| if (finder.size() != 1) {
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| return super.visit(node, data);
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| } |
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| ASTReturnStatement rs = (ASTReturnStatement) finder.get(0);
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| finder.clear();
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| rs.findChildrenOfType(ASTPrimaryExpression.class, finder, true);
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| ASTPrimaryExpression ape = (ASTPrimaryExpression) finder.get(0);
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| Node lastChild = ape.jjtGetChild(ape.jjtGetNumChildren() - 1);
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| String returnVariableName = null;
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| if (lastChild instanceof ASTPrimaryPrefix) {
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| returnVariableName = getNameFromPrimaryPrefix((ASTPrimaryPrefix) lastChild);
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| } |
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| if (returnVariableName == null) {
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| return super.visit(node, data);
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| } |
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| finder.clear();
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| node.findChildrenOfType(ASTIfStatement.class, finder, true);
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| if (finder.size() == 2) {
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| ASTIfStatement is = (ASTIfStatement) finder.get(0);
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| if (ifVerify(is, returnVariableName)) {
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| finder.clear();
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| is.findChildrenOfType(ASTSynchronizedStatement.class, finder, true);
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| if (finder.size() == 1) {
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| ASTSynchronizedStatement ss = (ASTSynchronizedStatement) finder.get(0);
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| finder.clear();
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| ss.findChildrenOfType(ASTIfStatement.class, finder, true);
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| if (finder.size() == 1) {
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| ASTIfStatement is2 = (ASTIfStatement) finder.get(0);
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| if (ifVerify(is2, returnVariableName)) {
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| finder.clear();
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| is2.findChildrenOfType(ASTStatementExpression.class, finder, true);
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| if (finder.size() == 1) {
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| ASTStatementExpression se = (ASTStatementExpression) finder.get(0);
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| if (se.jjtGetNumChildren() == 3) {
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| if (se.jjtGetChild(0) instanceof ASTPrimaryExpression) {
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| ASTPrimaryExpression pe = (ASTPrimaryExpression) se.jjtGetChild(0);
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| if (matchName(pe, returnVariableName)) {
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| if (se.jjtGetChild(1) instanceof ASTAssignmentOperator) {
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| addViolation(data, node);
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| } |
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| } |
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| } |
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| } |
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| } |
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| } |
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| } |
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| } |
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| } |
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| } |
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| return super.visit(node, data);
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| } |
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| private boolean ifVerify(ASTIfStatement is, String varname) {
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| List finder = new ArrayList();
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| is.findChildrenOfType(ASTPrimaryExpression.class, finder, true);
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| if (finder.size() > 1) {
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| ASTPrimaryExpression apeLeft = (ASTPrimaryExpression) finder.get(0);
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| if (matchName(apeLeft, varname)) {
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| ASTPrimaryExpression apeRight = (ASTPrimaryExpression) finder.get(1);
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| if ((apeRight.jjtGetNumChildren() == 1) && (apeRight.jjtGetChild(0) instanceof ASTPrimaryPrefix)) {
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| ASTPrimaryPrefix pp2 = (ASTPrimaryPrefix) apeRight.jjtGetChild(0);
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| if ((pp2.jjtGetNumChildren() == 1) && (pp2.jjtGetChild(0) instanceof ASTLiteral)) {
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| ASTLiteral lit = (ASTLiteral) pp2.jjtGetChild(0);
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| if ((lit.jjtGetNumChildren() == 1) && (lit.jjtGetChild(0) instanceof ASTNullLiteral)) {
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| return true;
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| } |
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| } |
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| } |
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| } |
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| } |
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| return false;
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| } |
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| private boolean matchName(ASTPrimaryExpression ape, String name) {
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| if ((ape.jjtGetNumChildren() == 1) && (ape.jjtGetChild(0) instanceof ASTPrimaryPrefix)) {
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| ASTPrimaryPrefix pp = (ASTPrimaryPrefix) ape.jjtGetChild(0);
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| String name2 = getNameFromPrimaryPrefix(pp);
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| if (name2 != null && name2.equals(name)) {
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| return true;
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| } |
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| } |
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| return false;
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| } |
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| private String getNameFromPrimaryPrefix(ASTPrimaryPrefix pp) {
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| if ((pp.jjtGetNumChildren() == 1) && (pp.jjtGetChild(0) instanceof ASTName)) {
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| return ((ASTName) pp.jjtGetChild(0)).getImage();
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| } |
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| return null;
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| } |
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| } |