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Merge branch 'pr-1534'

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Andreas Dangel
2018-12-27 10:30:24 +01:00
parent 43098c1cf0 db25def6b0
commit a81403c842
4 changed files with 118 additions and 0 deletions
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6
docs/pages/release_notes.md
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@ -25,6 +25,10 @@ This is a {{ site.pmd.release_type }} release.
for loop variables that are reassigned. Changing the loop variables additionally to the loop itself can lead to
hard-to-find bugs.
* The new Java rule {% rule "java/codestyle/UseDiamondOperator" %} (`java-codestyle`) looks for constructor
calls with explicit type parameters. Since Java 1.7, these type parameters are not necessary anymore, as they
can be inferred now.
#### Modified Rules
* The Java rule {% rule "java/codestyle/LocalVariableCouldBeFinal" %} (`java-codestyle`) has a new
@ -41,6 +45,7 @@ This is a {{ site.pmd.release_type }} release.
* [#1519](https://github.com/pmd/pmd/issues/1519): \[java] New rule: ForLoopVariableCount
* java-codestyle
* [#1513](https://github.com/pmd/pmd/issues/1513): \[java] LocalVariableCouldBeFinal: allow excluding the variable in a for-each loop
* [#1517](https://github.com/pmd/pmd/issues/1517): \[java] New Rule: UseDiamondOperator
* java-errorprone
* [#1035](https://github.com/pmd/pmd/issues/1035): \[java] ReturnFromFinallyBlock: False positive on lambda expression in finally block
* plsql
@ -58,6 +63,7 @@ This is a {{ site.pmd.release_type }} release.
* [#1520](https://github.com/pmd/pmd/pull/1520): \[java] New rule: ForLoopVariableCount: check the number of control variables in a for loop - [Kris Scheibe](https://github.com/kris-scheibe)
* [#1521](https://github.com/pmd/pmd/pull/1521): \[java] Upgrade to ASM7 for JDK 11 support - [Mark Pritchard](https://github.com/markpritchard)
* [#1530](https://github.com/pmd/pmd/pull/1530): \[java] New rule: AvoidReassigningLoopVariables - [Kris Scheibe](https://github.com/kris-scheibe)
* [#1534](https://github.com/pmd/pmd/pull/1534): \[java] This is the change regarding the usediamondoperator #1517 - [hemanshu070](https://github.com/hemanshu070)
{% endtocmaker %}

39
pmd-java/src/main/resources/category/java/codestyle.xml
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@ -1911,6 +1911,45 @@ public class Foo {
</example>
</rule>
<rule name="UseDiamondOperator"
language="java"
since="6.11.0"
message="Explicit type arguments can be replaced by Diamond Operator"
class="net.sourceforge.pmd.lang.rule.XPathRule"
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_codestyle.html#usediamondoperator"
minimumLanguageVersion="1.7">
<description>
Use the diamond operator to let the type be inferred automatically. With the Diamond operator it is possible
to avoid duplication of the type parameters.
Instead, the compiler is now able to infer the parameter types for constructor calls,
which makes the code also more readable.
</description>
<priority>1</priority>
<properties>
<property name="xpath">
<value>
<![CDATA[
//VariableInitializer
//PrimaryExpression[not(PrimarySuffix)]
[not(ancestor::ArgumentList)]
/PrimaryPrefix/AllocationExpression[ClassOrInterfaceType[@AnonymousClass='false']/TypeArguments//ReferenceType[not(.//TypeArguments)]]
|
//StatementExpression[AssignmentOperator][PrimaryExpression/PrimaryPrefix[not(Expression)]]
//PrimaryExpression[not(PrimarySuffix)]
[not(ancestor::ArgumentList)]
/PrimaryPrefix/AllocationExpression[ClassOrInterfaceType[@AnonymousClass='false']/TypeArguments//ReferenceType[not(.//TypeArguments)]]
]]>
</value>
</property>
</properties>
<example>
<![CDATA[
List<String> strings = new ArrayList<String>(); // unnecessary duplication of type parameters
List<String> stringsWithDiamond = new ArrayList<>(); // using the diamond operator is more concise
]]>
</example>
</rule>
<rule name="UselessParentheses"
language="java"
since="5.0"

11
pmd-java/src/test/java/net/sourceforge/pmd/lang/java/rule/codestyle/UseDiamondOperator.java Normal file
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@ -0,0 +1,11 @@
/**
* BSD-style license; for more info see http://pmd.sourceforge.net/license.html
*/
package net.sourceforge.pmd.lang.java.rule.codestyle;
import net.sourceforge.pmd.testframework.PmdRuleTst;
public class UseDiamondOperator extends PmdRuleTst {
// no additional unit tests
}

62
pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/codestyle/xml/UseDiamondOperator.xml Normal file
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@ -0,0 +1,62 @@
<?xml version="1.0" encoding="UTF-8"?>
<test-data
xmlns="http://pmd.sourceforge.net/rule-tests"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://pmd.sourceforge.net/rule-tests http://pmd.sourceforge.net/rule-tests_1_0_0.xsd">
<test-code>
<description>Use Diamond</description>
<expected-problems>2</expected-problems>
<expected-linenumbers>8,11</expected-linenumbers>
<code><![CDATA[
import java.util.ArrayList;
import java.util.List;
public class Foo {
List<String> field;
public void foo() {
List<String> strings = new ArrayList<String>();
List<String> strings2 = new ArrayList<>();
this.field = new ArrayList<String>();
}
}
]]></code>
</test-code>
<test-code>
<description>False positive cases: anonymous classes, methods calls</description>
<expected-problems>0</expected-problems>
<code><![CDATA[
public class Foo {
private WeakReference<Class<?>> typeReference;
public void foo() {
Collections.sort(files, new Comparator<DataSource>() {
@Override
public int compare(DataSource left, DataSource right) {
String leftString = left.getNiceFileName(useShortNames, inputPaths);
String rightString = right.getNiceFileName(useShortNames, inputPaths);
return leftString.compareTo(rightString);
}
});
final TreeSet<Map.Entry<String, TimedResult>> sortedKeySet = new TreeSet<>(
new Comparator<Map.Entry<String, TimedResult>>() {
@Override
public int compare(final Entry<String, TimedResult> o1, final Entry<String, TimedResult> o2) {
return Long.compare(o1.getValue().selfTimeNanos.get(), o2.getValue().selfTimeNanos.get());
}
});
new ThreadLocal<Queue<TimerEntry>>() {
@Override
protected Queue<TimerEntry> initialValue() {
return Collections.asLifoQueue(new LinkedList<TimerEntry>());
}
};
Iterator<Node> EMPTY_ITERATOR = new ArrayList<Node>().iterator();
Class<?> type = null;
typeReference = new WeakReference<Class<?>>(type);
((ListNode<E>) rev).reverseCache = new SoftReference<ImmutableList<E>>(this);
}
public Map<PropertyDescriptor<?>, Object> getOverriddenPropertiesByPropertyDescriptor() {
return propertyValues == null ? new HashMap<PropertyDescriptor<?>, Object>() : new HashMap<>(propertyValues);
}
}
]]></code>
</test-code>
</test-data>