IDEA-63820 Allow "throws" to be placed on the new line without indent

1. Added ability to configure java formatter in a way to align 'throws' keyword to method start;
2. Corresponding tests are added;

java/java-impl/src/com/intellij/ide/JavaLanguageCodeStyleSettingsProvider.java

@@ -215,7 +215,8 @@ public class JavaLanguageCodeStyleSettingsProvider extends LanguageCodeStyleSett
                                                      "        x--;\n" +
                                                      "    } while (x > 10) \n" +
                                                      "  }\n" +
-                                                     "    public static void test() { \n" +
+                                                     "    public static void test() \n" +
+                                                     "        throws Exception { \n" +
                                                      "        foo.foo().bar(\"arg1\", \n" +
                                                      "                      \"arg2\"); \n" +
                                                      "    } \n" +

java/java-impl/src/com/intellij/psi/formatter/java/AbstractJavaBlock.java

@@ -823,6 +823,7 @@ public abstract class AbstractJavaBlock extends AbstractBlock implements JavaBlo
       if (role == ChildRole.TYPE_PARAMETER_LIST) return defaultAlignment;
       if (role == ChildRole.TYPE) return defaultAlignment;
       if (role == ChildRole.NAME) return defaultAlignment;
+      if (role == ChildRole.THROWS_LIST && mySettings.ALIGN_THROWS_KEYWORD) return defaultAlignment;
       return null;
     }
 

java/java-tests/testSrc/com/intellij/psi/formatter/java/JavaFormatterAlignmentTest.java

@@ -251,4 +251,26 @@ public class JavaFormatterAlignmentTest extends AbstractJavaFormatterTest {
       "}"
     );
   }
+  
+  public void testAlignThrowsKeyword() throws Exception {
+    // Inspired by IDEA-63820
+    
+    getSettings().ALIGN_THROWS_KEYWORD = true;
+    doClassTest(
+      "public void test()\n" +
+      "                 throws Exception {}",
+      "public void test()\n" +
+      "throws Exception {\n" +
+      "}"
+    );
+
+    getSettings().ALIGN_THROWS_KEYWORD = false;
+    doClassTest(
+      "public void test()\n" +
+      "                 throws Exception {}",
+      "public void test()\n" +
+      "        throws Exception {\n" +
+      "}"
+    );
+  }
 }

platform/lang-api/src/com/intellij/psi/codeStyle/CommonCodeStyleSettings.java

@@ -299,6 +299,7 @@ public class CommonCodeStyleSettings {
   public boolean ALIGN_MULTILINE_ASSIGNMENT = false;
   public boolean ALIGN_MULTILINE_TERNARY_OPERATION = false;
   public boolean ALIGN_MULTILINE_THROWS_LIST = false;
+  public boolean ALIGN_THROWS_KEYWORD = false;
 
   public boolean ALIGN_MULTILINE_EXTENDS_LIST = false;
   public boolean ALIGN_MULTILINE_METHOD_BRACKETS = false;

platform/lang-impl/src/com/intellij/application/options/codeStyle/WrappingAndBracesPanel.java

@@ -49,6 +49,7 @@ public class WrappingAndBracesPanel extends OptionTableWithPreviewPanel {
 
     addOption("THROWS_LIST_WRAP", WRAPPING_THROWS_LIST, WRAP_OPTIONS, WRAP_VALUES);
     addOption("ALIGN_MULTILINE_THROWS_LIST", ApplicationBundle.message("wrapping.align.when.multiline"), WRAPPING_THROWS_LIST);
+    addOption("ALIGN_THROWS_KEYWORD", ApplicationBundle.message("wrapping.align.throws.keyword"), WRAPPING_THROWS_LIST);
     addOption("THROWS_KEYWORD_WRAP", WRAPPING_THROWS_KEYWORD, WRAP_OPTIONS_FOR_SINGLETON, WRAP_VALUES_FOR_SINGLETON);
 
     addOption("METHOD_PARAMETERS_WRAP", WRAPPING_METHOD_PARAMETERS, WRAP_OPTIONS, WRAP_VALUES);

platform/platform-resources-en/src/messages/ApplicationBundle.properties

@@ -180,6 +180,7 @@ wrapping.extends.implements.list=Extends/implements list
 wrapping.extends.implements.keyword=Extends/implements keyword
 wrapping.throws.list=Throws list
 wrapping.throws.keyword=Throws keyword
+wrapping.align.throws.keyword=Align 'throws' to method start
 wrapping.ternary.operation=Ternary operation
 wrapping.assignment.variables.groups=Fields/variables groups
 wrapping.assignment.statement=Assignment statement