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Merge branch 'pr-303' into pmd/5.5.x

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This commit is contained in:
Juan Martín Sotuyo Dodero
2017-03-22 15:40:43 -03:00
parent f70690b511 133f3d99df
commit e261b71258
3 changed files with 82 additions and 18 deletions
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48
pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/strings/InefficientEmptyStringCheckRule.java
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@ -4,49 +4,63 @@
package net.sourceforge.pmd.lang.java.rule.strings;
import net.sourceforge.pmd.lang.ast.Node;
import net.sourceforge.pmd.lang.java.ast.ASTPrimaryExpression;
import net.sourceforge.pmd.lang.java.rule.AbstractInefficientZeroCheck;
import net.sourceforge.pmd.lang.java.symboltable.JavaNameOccurrence;
/**
* This rule finds code which inefficiently determines empty strings. This code
* <p/>
*
*
* <pre>
* if(str.trim().length()==0){....
* </pre>
*
* <p/> is quite inefficient as trim() causes a new String to be created.
* Smarter code to check for an empty string would be: <p/>
*
*
* <p>
* is quite inefficient as trim() causes a new String to be created. Smarter
* code to check for an empty string would be:
* </p>
*
* <pre>
* Character.isWhitespace(str.charAt(i));
* </pre>
*
*
* @author acaplan
*/
public class InefficientEmptyStringCheckRule extends AbstractInefficientZeroCheck {
/**
* Determine if we're dealing with String.length method
*
* @param occ
* The name occurrence
* @return true if it's String.length, else false
*/
@Override
public boolean isTargetMethod(JavaNameOccurrence occ) {
if (occ.getNameForWhichThisIsAQualifier() != null
&& occ.getNameForWhichThisIsAQualifier().getImage().indexOf("trim") != -1) {
Node pExpression = occ.getLocation().jjtGetParent().jjtGetParent();
if (pExpression.jjtGetNumChildren() >= 3
&& "length".equals(pExpression.jjtGetChild(2).getImage())) {
if (pExpression.jjtGetNumChildren() > 2 && "length".equals(pExpression.jjtGetChild(2).getImage())) {
return true;
}
}
return false;
}
@Override
public boolean appliesToClassName(String name) {
return "String".equals(name);
}
}
@Override
public Object visit(ASTPrimaryExpression node, Object data) {
if (node.jjtGetNumChildren() > 3) {
// Check last suffix
if (!"isEmpty".equals(node.jjtGetChild(node.jjtGetNumChildren() - 2).getImage())) {
return data;
}
Node prevCall = node.jjtGetChild(node.jjtGetNumChildren() - 4);
String target = prevCall.jjtGetNumChildren() > 0 ? prevCall.jjtGetChild(0).getImage() : prevCall.getImage();
if (target != null && "trim".equals(target) || target.endsWith(".trim")) {
addViolation(data, node);
}
}
return data;
}
}

48
pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/strings/xml/InefficientEmptyStringCheck.xml
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@ -132,4 +132,52 @@ public class Foo {
}
]]></code>
</test-code>
<test-code>
<description><![CDATA[
String.trim().isEmpty() is called, should have failed
]]></description>
<expected-problems>1</expected-problems>
<code><![CDATA[
public class Foo {
void bar() {
String foo = "foo";
boolean b = foo.trim().isEmpty();
}
}
]]></code>
</test-code>
<test-code>
<description><![CDATA[
String.trim().isEmpty() is called after a chain call, should have failed
]]></description>
<expected-problems>2</expected-problems>
<code><![CDATA[
public class Foo {
void bar() {
String foo = "foo";
boolean b = Arrays.toString(foo.toCharArray()).trim().isEmpty();
int i = 2;
b = String.valueOf(i).trim().isEmpty();
}
}
]]></code>
</test-code>
<test-code>
<description><![CDATA[
String.trim().isEmpty() is called after a chain call, should have failed twice
]]></description>
<expected-problems>2</expected-problems>
<code><![CDATA[
public class Foo {
void bar() {
String foo = "foo";
boolean b = Arrays.toString(foo.toCharArray()).trim().isEmpty();
b = String.valueOf(2).trim().isEmpty();
}
}
]]></code>
</test-code>
</test-data>

4
src/site/markdown/overview/changelog.md
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@ -21,6 +21,8 @@ The PMD team is pleased to announce PMD 5.5.5.
* [#275](https://github.com/pmd/pmd/issues/275): \[java] FinalFieldCouldBeStatic: Constant in @interface incorrectly reported as "could be made static"
* [#282](https://github.com/pmd/pmd/issues/282): \[java] UnnecessaryLocalBeforeReturn false positive when cloning Maps
* [#291](https://github.com/pmd/pmd/issues/291): \[java] Improve quality of AccessorClassGeneration
* java-strings:
* [#290](https://github.com/pmd/pmd/issues/290): \[java] InefficientEmptyStringCheck misses String.trim().isEmpty()
### API Changes
@ -29,4 +31,4 @@ The PMD team is pleased to announce PMD 5.5.5.
* [#280](https://github.com/pmd/pmd/pull/280): \[apex] Support for Aggregate Result in CRUD rules
* [#289](https://github.com/pmd/pmd/pull/289): \[apex] Complex SOQL Crud check bug fixes
* [#296](https://github.com/pmd/pmd/pull/296): \[apex] Adding String.IsNotBlank to the whitelist to prevent False positives
* [#303](https://github.com/pmd/pmd/pull/303): \[java] InefficientEmptyStringCheckRule now reports String.trim().isEmpty()