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| package net.sourceforge.pmd.rules.strings; |
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| import net.sourceforge.pmd.AbstractRule; |
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| import net.sourceforge.pmd.ast.ASTEqualityExpression; |
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| import net.sourceforge.pmd.ast.ASTLiteral; |
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| import net.sourceforge.pmd.ast.ASTPrimitiveType; |
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| import net.sourceforge.pmd.ast.ASTVariableDeclaratorId; |
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| import net.sourceforge.pmd.ast.Node; |
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| import net.sourceforge.pmd.ast.SimpleNode; |
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| import net.sourceforge.pmd.symboltable.NameOccurrence; |
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| import java.util.Iterator; |
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| import java.util.List; |
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| public class InefficientEmptyStringCheck extends AbstractRule { |
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| public Object visit(ASTVariableDeclaratorId node, Object data) {
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| SimpleNode nameNode = node.getTypeNameNode();
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| if (nameNode instanceof ASTPrimitiveType) {
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| return data;
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| } |
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| if (!"String".equals(node.getNameDeclaration().getTypeImage())) {
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| return data;
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| } |
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| List declars = node.getUsages();
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| for (Iterator i = declars.iterator(); i.hasNext();) {
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| NameOccurrence occ = (NameOccurrence) i.next();
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| if (!isStringLength(occ)) {
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| continue;
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| } |
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| ASTEqualityExpression equality = (ASTEqualityExpression) occ
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| .getLocation().getFirstParentOfType(ASTEqualityExpression.class); |
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| if (equality != null && isCompareZero(equality)) {
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| addViolation(data, occ.getLocation());
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| } |
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| } |
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| return data;
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| } |
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| private boolean isCompareZero(ASTEqualityExpression equality) {
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| return (checkComparison(equality, 0) || checkComparison(equality, 1));
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| } |
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| private boolean isStringLength(NameOccurrence occ) {
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| if (occ.getNameForWhichThisIsAQualifier() != null
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| && occ.getNameForWhichThisIsAQualifier().getImage().indexOf("trim") != -1) { |
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| Node pExpression = occ.getLocation().jjtGetParent().jjtGetParent();
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| if (pExpression.jjtGetNumChildren() >= 3
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| && "length" |
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| .equals(((SimpleNode) pExpression.jjtGetChild(2)) |
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| .getImage())) { |
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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 boolean checkComparison(ASTEqualityExpression equality, int i) {
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| return (equality.jjtGetChild(i).jjtGetChild(0).jjtGetChild(0) instanceof ASTLiteral && "0"
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| .equals(((SimpleNode) equality.jjtGetChild(i).jjtGetChild(0) |
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| .jjtGetChild(0)).getImage())); |
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| } |
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| } |