Merge branch for pr #1647

docs/pages/release_notes.md

@@ -59,6 +59,9 @@ CPD also parses raw string literals now correctly (see [#1784](https://github.co
     conventions for property declarations. By default this rule uses the standard Apex naming convention (Camel case),
     but it can be configured through properties.
 
+*   The new Java rule {% rule "java/codestyle/UseShortArrayInitializer" %} (`java-codestyle`) searches for
+    array initialization expressions, which can be written shorter.
+
 #### Modified Rules
 
 *   The Apex rule {% rule "apex/codestyle/ClassNamingConventions" %} (`apex-codestyle`) can now be configured
@@ -105,6 +108,7 @@ CPD also parses raw string literals now correctly (see [#1784](https://github.co
 *   java-bestpractices
     *   [#1738](https://github.com/pmd/pmd/issues/1738): \[java] MethodReturnsInternalArray does not work in inner classes
 *   java-codestyle
+    *   [#1495](https://github.com/pmd/pmd/issues/1495): \[java] Rule to detect overly verbose array initializiation
     *   [#1684](https://github.com/pmd/pmd/issues/1684): \[java] Properly whitelist serialPersistentFields
     *   [#1804](https://github.com/pmd/pmd/issues/1804): \[java] NPE in UnnecessaryLocalBeforeReturnRule
 *   python
@@ -134,6 +138,7 @@ CPD also parses raw string literals now correctly (see [#1784](https://github.co
 
 ### External Contributions
 
+*   [#1647](https://github.com/pmd/pmd/pull/1647): \[java] Rule to detect overly verbose array initialization - [Victor](https://github.com/IDoCodingStuffs)
 *   [#1798](https://github.com/pmd/pmd/pull/1798): \[java] Make CommentDefaultAccessModifier work for top-level classes - [Boris Petrov](https://github.com/boris-petrov)
 *   [#1799](https://github.com/pmd/pmd/pull/1799): \[java] MethodReturnsInternalArray does not work in inner classes - Fixed #1738 - [Srinivasan Venkatachalam](https://github.com/Srini1993)
 *   [#1802](https://github.com/pmd/pmd/pull/1802): \[python] \[cpd] Add support for Python 2 backticks - [Maikel Steneker](https://github.com/maikelsteneker)

pmd-core/src/main/resources/rulesets/releases/6150.xml

@@ -13,5 +13,6 @@ This ruleset contains links to rules that are new in PMD v6.15.0
     <rule ref="category/apex/codestyle.xml/LocalVariableNamingConventions"/>
     <rule ref="category/apex/codestyle.xml/PropertyNamingConventions"/>
 
+    <rule ref="category/java/codestyle.xml/UseShortArrayInitializer"/>
 </ruleset>
 

pmd-java/src/main/resources/category/java/codestyle.xml

@@ -2117,6 +2117,39 @@ public class Foo {
         </example>
     </rule>
 
+    <rule name="UseShortArrayInitializer"
+        language="java"
+        since="6.15.0"
+        message="Array initialization can be written shorter"
+        class="net.sourceforge.pmd.lang.rule.XPathRule"
+        externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_codestyle.html#useshortarrayinitializer">
+        <description>
+<![CDATA[
+When declaring and initializing array fields or variables, it is not necessary to explicitly create a new array
+using `new`. Instead one can simply define the initial content of the array as a expression in curly braces.
+
+E.g. `int[] x = new int[] { 1, 2, 3 };` can be written as `int[] x = { 1, 2, 3 };`.
+]]>
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="xpath">
+                <value><![CDATA[
+//VariableDeclarator
+    [VariableDeclaratorId[@ArrayType = true() and @TypeInferred = false()]]
+    [VariableInitializer/Expression/PrimaryExpression/PrimaryPrefix/AllocationExpression/ArrayDimsAndInits/ArrayInitializer]
+                ]]></value>
+            </property>
+            <property name="version" value="2.0"/>
+        </properties>
+        <example>
+<![CDATA[
+Foo[] x = new Foo[] { ... }; // Overly verbose
+Foo[] x = { ... }; //Equivalent to above line
+]]>
+        </example>
+    </rule>
+
     <rule name="VariableNamingConventions"
           since="1.2"
           deprecated="true"

pmd-java/src/test/java/net/sourceforge/pmd/lang/java/rule/codestyle/UseShortArrayInitializerTest.java

@@ -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 UseShortArrayInitializerTest extends PmdRuleTst {
+  // no additional unit tests
+}

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/codestyle/xml/UseShortArrayInitializer.xml

@@ -0,0 +1,96 @@
+<?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>simple failure case</description>
+        <expected-problems>1</expected-problems>
+        <expected-linenumbers>3</expected-linenumbers>
+        <code><![CDATA[
+public class UseShortArrayExample {
+    void foo() {
+        int[] x = new int[] {1,2,3};
+    }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>case with two initializers</description>
+        <expected-problems>2</expected-problems>
+        <expected-linenumbers>3,3</expected-linenumbers>
+        <code><![CDATA[
+public class UseShortArrayExample {
+    void foo() {
+        int ar[] = new int[] { 1,2,3}, foo[] = new int[] { 4, 5, 6 };
+    }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>ok</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+public class UseShortArrayExample {
+    void foo() {
+        int[] x = {1,2,3};
+    }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>assignment needs to use new</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+public class UseShortArrayExample {
+    void foo() {
+        int[] a = { 1 };
+        a = new int[] { 2 }; // can't be replaced
+    }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>empty array initialization</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+public class UseShortArrayExample {
+    public void foo() {
+        int[] a = new int[3]; // no violation
+    }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>array initialization with fields</description>
+        <expected-problems>3</expected-problems>
+        <expected-linenumbers>2,3,3</expected-linenumbers>
+        <code><![CDATA[
+public class UseShortArrayExample {
+    private int[] f1 = new int[] {1,2,3};
+    private int[] f2 = new int[] {1,2,3}, f3 = new int[] { 4,5,6 };
+
+    private int[] good = { 1,2,3 };
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>array initialization with var</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+public class UseShortArrayExample {
+    public void foo() {
+        var ar1 = new int[] { 1, 2 };
+        //var ar2 = { 1, 2 }; // this is actually a compile-time error and is forbidden. See JLS 14.4.
+    }
+}
+        ]]></code>
+    </test-code>
+</test-data>