Issue checkstyle#14726: new check: ConstructorsDeclarationGroupingCheck

config/checkstyle-checks.xml

@@ -539,6 +539,7 @@
     <module name="NoFinalizer"/>
     <module name="OneStatementPerLine"/>
     <module name="OverloadMethodsDeclarationOrder"/>
+    <module name="ConstructorsDeclarationGrouping"/>
     <module name="PackageDeclaration"/>
     <module name="ParameterAssignment"/>
     <module name="RequireThis"/>

config/jsoref-spellchecker/whitelist.words

@@ -984,6 +984,7 @@ outertypenumber
 outter
 ove
 overloadmethodsdeclarationorder
+constructorsdeclarationgrouping
 overloadsplit
 overridable
 OVERRIDERS

src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionConstructorsDeclarationGroupingTest.java

@@ -0,0 +1,52 @@
+package org.checkstyle.suppressionxpathfilter;
+
+import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
+import com.puppycrawl.tools.checkstyle.checks.coding.ConstructorsDeclarationGroupingCheck;
+import com.puppycrawl.tools.checkstyle.checks.coding.OverloadMethodsDeclarationOrderCheck;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.util.Arrays;
+import java.util.List;
+
+public class XpathRegressionConstructorsDeclarationGroupingTest extends AbstractXpathTestSupport{
+
+    private final Class<ConstructorsDeclarationGroupingCheck> clazz =
+            ConstructorsDeclarationGroupingCheck.class;
+    @Override
+    protected String getCheckName() {
+        return clazz.getSimpleName();
+    }
+
+    @Test
+    public void testOne() throws Exception {
+        final File fileToProcess = new File(
+                getPath("SuppressionXpathRegressionConstructorsDeclarationGrouping1.java"));
+
+        final DefaultConfiguration moduleConfig = createModuleConfig(clazz);
+
+        final String[] expectedViolation = {
+                "10:5: " + getCheckMessage(clazz,
+                        ConstructorsDeclarationGroupingCheck.MSG_KEY),
+        };
+
+        final List<String> expectedXpathQueries = Arrays.asList(
+                "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
+                        + "[@text='SuppressionXpathRegressionConstructorsDeclarationGrouping1']]"
+                        + "/OBJBLOCK/CTOR_DEF[./IDENT"
+                        + "[@text='SuppressionXpathRegressionConstructorsDeclarationGrouping1']]",
+                "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
+                        + "[@text='SuppressionXpathRegressionConstructorsDeclarationGrouping1']]"
+                        + "/OBJBLOCK/CTOR_DEF[./IDENT"
+                        + "[@text='SuppressionXpathRegressionConstructorsDeclarationGrouping1']]"
+                        + "/MODIFIERS",
+                "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
+                        + "[@text='SuppressionXpathRegressionConstructorsDeclarationGrouping1']]"
+                        + "/OBJBLOCK/CTOR_DEF/IDENT"
+                        + "[@text='SuppressionXpathRegressionConstructorsDeclarationGrouping1']"
+
+        );
+
+        runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
+    }
+}

src/it/resources/org/checkstyle/suppressionxpathfilter/constructorsdeclarationgrouping/SuppressionXpathRegressionConstructorsDeclarationGrouping1.java

@@ -0,0 +1,11 @@
+package org.checkstyle.suppressionxpathfilter.constructorsdeclarationgrouping;
+
+public class SuppressionXpathRegressionConstructorsDeclarationGrouping1 {
+    SuppressionXpathRegressionConstructorsDeclarationGrouping1() {}
+
+    SuppressionXpathRegressionConstructorsDeclarationGrouping1(int a) {}
+
+    int x;
+
+    SuppressionXpathRegressionConstructorsDeclarationGrouping1(String str) {} // warn
+}

src/main/java/com/puppycrawl/tools/checkstyle/PackageObjectFactory.java

@@ -557,6 +557,8 @@ private static void fillChecksFromCodingPackage() {
                 BASE_PACKAGE + ".checks.coding.OneStatementPerLineCheck");
         NAME_TO_FULL_MODULE_NAME.put("OverloadMethodsDeclarationOrderCheck",
                 BASE_PACKAGE + ".checks.coding.OverloadMethodsDeclarationOrderCheck");
+        NAME_TO_FULL_MODULE_NAME.put("ConstructorsDeclarationGroupingCheck",
+                BASE_PACKAGE + ".checks.coding.ConstructorsDeclarationGroupingCheck");
         NAME_TO_FULL_MODULE_NAME.put("PackageDeclarationCheck",
                 BASE_PACKAGE + ".checks.coding.PackageDeclarationCheck");
         NAME_TO_FULL_MODULE_NAME.put("ParameterAssignmentCheck",

src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/ConstructorsDeclarationGroupingCheck.java

@@ -0,0 +1,107 @@
+///////////////////////////////////////////////////////////////////////////////////////////////
+// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
+// Copyright (C) 2001-2024 the original author or authors.
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+///////////////////////////////////////////////////////////////////////////////////////////////
+
+package com.puppycrawl.tools.checkstyle.checks.coding;
+
+import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
+import com.puppycrawl.tools.checkstyle.GlobalStatefulCheck;
+import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
+import com.puppycrawl.tools.checkstyle.api.DetailAST;
+import com.puppycrawl.tools.checkstyle.api.TokenTypes;
+
+import java.util.Objects;
+
+/**
+ * <p>
+ * Checks that overloaded constructors are grouped together.
+ * If there is anything between overloaded constructors ( obviously, expect comments )
+ * then this check will give an error.
+ * </p>
+ * <p>
+ * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
+ * </p>
+ * <p>
+ * Violation Message Keys:
+ * </p>
+ * <ul>
+ * <li>
+ * {@code constructors.declaration.grouping}
+ * </li>
+ * </ul>
+ *
+ * @since 10.15.0
+ */
+
+@FileStatefulCheck
+public class ConstructorsDeclarationGroupingCheck extends AbstractCheck {
+
+    /**
+     * A key is pointing to the warning message text in "messages.properties"
+     * file.
+     */
+    public static final String MSG_KEY = "constructors.declaration.grouping";
+
+    /** Specifies if the constructor has occurred before. */
+    private boolean isCtorOccurred;
+
+    /** Specifies the previous IDENT name. */
+    private String previousIdent;
+
+    @Override
+    public int[] getDefaultTokens() {
+        return getRequiredTokens();
+    }
+
+    @Override
+    public int[] getAcceptableTokens() {
+        return getRequiredTokens();
+    }
+
+    @Override
+    public int[] getRequiredTokens() {
+        return new int[]{
+            TokenTypes.CTOR_DEF,
+        };
+    }
+
+    @Override
+    public void visitToken(DetailAST ast) {
+        final DetailAST previousSibling = ast.getPreviousSibling();
+
+        if (previousSibling != null) {
+            final DetailAST parent = ast.getParent().getParent();
+            final String ident = parent.findFirstToken(TokenTypes.IDENT).getText();
+
+            if (!Objects.equals(ident, previousIdent)) {
+                isCtorOccurred = false;
+                previousIdent = ident;
+            }
+
+            final int siblingType = previousSibling.getType();
+
+            if (siblingType != TokenTypes.CTOR_DEF && !isCtorOccurred) {
+                isCtorOccurred = true;
+            }
+            else if (siblingType != TokenTypes.CTOR_DEF) {
+                log(ast, MSG_KEY);
+            }
+        }
+
+    }
+}

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages.properties

@@ -3,6 +3,7 @@ assignment.inner.avoid=Inner assignments should be avoided.
 avoid.clone.method=Avoid using clone method.
 avoid.double.brace.init=Avoid double brace initialization.
 avoid.finalizer.method=Avoid using finalizer method.
+constructors.declaration.grouping=All overloaded constructors should be grouped together
 covariant.equals=covariant equals without overriding equals(java.lang.Object).
 declaration.order.access=Variable access definition in wrong order.
 declaration.order.constructor=Constructor definition in wrong order.

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_zh.properties

@@ -3,6 +3,7 @@ assignment.inner.avoid=应避免在子表达式中赋值。
 avoid.clone.method=避免重写 clone 方法。
 avoid.double.brace.init=避免双括号初始化。
 avoid.finalizer.method=避免重写finalize方法。
+constructors.declaration.grouping=????????????????
 covariant.equals=重写''equals()''方法时，必须确保重写了''equals(java.lang.Object)''方法。
 declaration.order.access=属性访问器定义顺序错误。
 declaration.order.constructor=构造器定义顺序错误。

src/main/resources/com/puppycrawl/tools/checkstyle/meta/checks/coding/ConstructorsDeclarationGrouping.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<checkstyle-metadata>
+  <module>
+    <check fully-qualified-name="com.puppycrawl.tools.checkstyle.checks.coding.ConstructorsDeclarationGroupingCheck"
+           name="ConstructorsDeclarationGrouping"
+           parent="com.puppycrawl.tools.checkstyle.TreeWalker">
+      <description>&lt;p&gt;
+        Checks that overloaded constructors are grouped together.
+        If there is anything between overloaded constructors ( obviously, expect comments )
+        then this check will give an error.
+        &lt;/p&gt;</description>
+      <message-keys>
+        <message-key key="constructors.declaration.grouping"/>
+      </message-keys>
+    </check>
+  </module>
+</checkstyle-metadata>

src/main/resources/com/puppycrawl/tools/checkstyle/meta/checks/coding/ConstructorsDeclarationGroupingCheck.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<checkstyle-metadata>
+   <module>
+      <check fully-qualified-name="com.puppycrawl.tools.checkstyle.checks.coding.ConstructorsDeclarationGroupingCheck"
+             name="ConstructorsDeclarationGrouping"
+             parent="com.puppycrawl.tools.checkstyle.TreeWalker">
+         <description>&lt;p&gt;
+ Checks that overloaded constructors are grouped together.
+ If there is anything between overloaded constructors ( obviously, expect comments )
+ then this check will give an error.
+ &lt;/p&gt;</description>
+         <message-keys>
+            <message-key key="constructors.declaration.grouping"/>
+         </message-keys>
+      </check>
+   </module>
+</checkstyle-metadata>

src/site/site.xml

@@ -149,6 +149,8 @@
           <item name="OneStatementPerLine" href="checks/coding/onestatementperline.html"/>
           <item name="OverloadMethodsDeclarationOrder"
                 href="checks/coding/overloadmethodsdeclarationorder.html"/>
+          <item name="ConstructorsDeclarationGrouping"
+                href="checks/coding/constructorsdeclarationgrouping.html"/>
           <item name="PackageDeclaration" href="checks/coding/packagedeclaration.html"/>
           <item name="ParameterAssignment" href="checks/coding/parameterassignment.html"/>
           <item name="RequireThis" href="checks/coding/requirethis.html"/>

src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ConstructorsDeclarationGroupingCheckTest.java

@@ -0,0 +1,25 @@
+package com.puppycrawl.tools.checkstyle.checks.coding;
+
+import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
+import org.junit.jupiter.api.Test;
+
+import static com.puppycrawl.tools.checkstyle.checks.coding.ConstructorsDeclarationGroupingCheck.MSG_KEY;
+
+public class ConstructorsDeclarationGroupingCheckTest extends AbstractModuleTestSupport {
+    @Override
+    protected String getPackageLocation() {
+        return "com/puppycrawl/tools/checkstyle/checks/coding/constructorsdeclarationgrouping";
+    }
+
+    @Test
+    public void testDefault() throws Exception {
+        final String[] expected = {
+                "23:5: " + getCheckMessage(MSG_KEY),
+                "27:5: " + getCheckMessage(MSG_KEY),
+                "40:9: " + getCheckMessage(MSG_KEY),
+                "51:13: " + getCheckMessage(MSG_KEY),
+        };
+        verifyWithInlineConfigParser(
+                getPath("InputConstructorsDeclarationGrouping.java"), expected);
+    }
+}

src/test/java/com/puppycrawl/tools/checkstyle/internal/XpathRegressionTest.java

@@ -200,6 +200,7 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
             "OuterTypeFilename",
             "OuterTypeNumber",
             "OverloadMethodsDeclarationOrder",
+            "ConstructorsDeclarationGrouping",
             "PackageName",
             "ParameterAssignment",
             "ParameterName",

src/test/java/com/puppycrawl/tools/checkstyle/meta/XmlMetaReaderTest.java

@@ -40,20 +40,20 @@ protected String getPackageLocation() {
 
     @Test
     public void test() {
-        assertThat(XmlMetaReader.readAllModulesIncludingThirdPartyIfAny()).hasSize(200);
+        assertThat(XmlMetaReader.readAllModulesIncludingThirdPartyIfAny()).hasSize(202);
     }
 
     @Test
     public void testDuplicatePackage() {
         assertThat(XmlMetaReader
                     .readAllModulesIncludingThirdPartyIfAny("com.puppycrawl.tools.checkstyle.meta"))
-                .hasSize(200);
+                .hasSize(202);
     }
 
     @Test
     public void testBadPackage() {
         assertThat(XmlMetaReader.readAllModulesIncludingThirdPartyIfAny("DOES.NOT.EXIST"))
-                .hasSize(200);
+                .hasSize(202);
     }
 
     @Test

src/test/resources/com/puppycrawl/tools/checkstyle/checks/coding/constructorsdeclarationgrouping/InputConstructorsDeclarationGrouping.java

@@ -0,0 +1,55 @@
+/*
+ConstructorsDeclarationGrouping
+
+
+*/
+
+package com.puppycrawl.tools.checkstyle.checks.coding.constructorsdeclarationgrouping;
+
+public class InputConstructorsDeclarationGrouping {
+
+    int a;
+
+    int b;
+
+    void foo() {}
+
+    InputConstructorsDeclarationGrouping() {}
+
+    InputConstructorsDeclarationGrouping(String a) {}
+
+    void foo2() {}
+
+    InputConstructorsDeclarationGrouping(int a) {} // violation
+
+    int abc;
+
+    InputConstructorsDeclarationGrouping(double x) {} // violation
+
+    private enum Testing {
+
+        one;
+
+        int x;
+        Testing() {}
+
+        Testing(String f) {}
+
+        String str;
+
+        Testing(int x) {} // violation
+
+        private abstract class Yo {
+            int x;
+
+            Yo(){}
+
+            Yo(int x) {}
+
+            String neko;
+
+            Yo(String g) {} // violation
+        }
+
+    }
+}

src/xdocs-examples/resources/com/puppycrawl/tools/checkstyle/checks/coding/constructorsdeclarationgrouping/Example1.java

@@ -0,0 +1,25 @@
+/*xml
+<module name="Checker">
+  <module name="TreeWalker">
+    <module name="ConstructorsDeclarationGrouping"/>
+  </module>
+</module>
+*/
+
+package com.puppycrawl.tools.checkstyle.checks.coding.constructorsdeclarationgrouping;
+
+// xdoc section -- start
+public class Example1 {
+    int x;
+
+    void foo() {}
+
+    Example1() {}
+
+    Example1(int a){}
+
+    void foo2() {}
+
+    Example1(String str) {} // violation
+}
+// xdoc section -- end