[reactor][java-uast] IDEA-314873: space between comment and code now is preserved

GitOrigin-RevId: 45c7f995af2c19b33a01cdb261186788285c869b

uast/uast-java-ide/src/org/jetbrains/uast/java/generate/JavaUastCodeGenerationPlugin.kt

@@ -138,18 +138,35 @@ internal class JavaUastCodeGenerationPlugin : UastCodeGenerationPlugin {
 
 private fun PsiElementFactory.createExpressionStatement(expression: PsiExpression, oldElement: UElement? = null): PsiStatement? {
   val comments = oldElement?.comments
-  val textStatement = if (comments.isNullOrEmpty()) "x;" else createStatementTextWithComment(comments)
-  
+  val textStatement = if (comments.isNullOrEmpty()) "x;" else createStatementTextWithComment(comments, oldElement)
+
   val statement = createStatementFromText(textStatement, null) as? PsiExpressionStatement ?: return null
 
   statement.expression.replace(expression)
   return statement
 }
 
-private fun createStatementTextWithComment(comments: List<UComment>): String {
-  val comment = comments.joinToString(separator = " ") { it.text }
+private fun createStatementTextWithComment(comments: List<UComment>, oldElement: UElement): String {
+  val comment = comments.joinToString(prefix = getCommentPrefix(comments, oldElement), separator = " ") { it.text }
+
+  return "x;$comment"
+}
+
+private fun getCommentPrefix(comments: List<UComment>, oldElement: UElement): String {
+  val lastCommentPsi = comments.last().sourcePsi
+  val sourcePsi = oldElement.sourcePsi
+  val defaultPrefix = " "
+  if (sourcePsi == null) return defaultPrefix
+
+  val isCommentInChildren = sourcePsi.children.filterIsInstance<PsiComment>().any { it == lastCommentPsi }
+  val siblings = if (isCommentInChildren) {
+    sourcePsi.firstChild.siblings()
+  } else {
+    sourcePsi.siblings(withSelf = false)
+  }
+  val beforeComment = siblings.takeWhile { it != lastCommentPsi }.lastOrNull()  
   
-  return "x; $comment"
+  return (beforeComment as? PsiWhiteSpace)?.text ?: defaultPrefix
 }
 
 class JavaUastElementFactory(private val project: Project) : UastElementFactory {
@@ -413,7 +430,6 @@ class JavaUastElementFactory(private val project: Project) : UastElementFactory
     return JavaUBlockExpression(blockStatement, null)
   }
 
-
   override fun createLambdaExpression(parameters: List<UParameterInfo>, body: UExpression, context: PsiElement?): ULambdaExpression? {
     //TODO: smart handling cases, when parameters types should exist in code
     val lambda = psiFactory.createExpressionFromText(

uast/uast-java/src/org/jetbrains/uast/java/internal/JavaUElementWithComments.kt

@@ -15,11 +15,14 @@
  */
 package org.jetbrains.uast.java.internal
 
-import com.intellij.psi.*
+import com.intellij.psi.PsiComment
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiWhiteSpace
 import org.jetbrains.uast.UComment
 import org.jetbrains.uast.UElement
 import org.jetbrains.uast.UExpression
 import org.jetbrains.uast.UParameter
+import org.jetbrains.uast.java.isSemicolon
 
 interface JavaUElementWithComments : UElement {
   override val comments: List<UComment>
@@ -41,10 +44,4 @@ interface JavaUElementWithComments : UElement {
     }
     return sibling as? PsiComment
   }
-
-  private fun PsiElement?.isSemicolon(): Boolean {
-    if (this !is PsiJavaToken) return false
-
-    return tokenType == JavaTokenType.SEMICOLON
-  }
 }
\ No newline at end of file

uast/uast-java/src/org/jetbrains/uast/java/internal/javaInternalUastUtils.kt

@@ -17,10 +17,7 @@ package org.jetbrains.uast.java
 
 import com.intellij.lang.Language
 import com.intellij.lang.java.JavaLanguage
-import com.intellij.psi.JavaTokenType
-import com.intellij.psi.PsiAnnotation
-import com.intellij.psi.PsiElement
-import com.intellij.psi.PsiModifierListOwner
+import com.intellij.psi.*
 import com.intellij.psi.impl.source.tree.CompositeElement
 import com.intellij.psi.tree.IElementType
 import org.jetbrains.uast.UDeclaration
@@ -94,3 +91,9 @@ internal fun <T> lazyPub(initializer: () -> T): Lazy<T> = lazy(LazyThreadSafetyM
 
 @Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
 internal inline fun <reified T : Any> Any?.asSafely(): @kotlin.internal.NoInfer T? = this as? T
+
+fun PsiElement?.isSemicolon(): Boolean {
+  if (this !is PsiJavaToken) return false
+
+  return tokenType == JavaTokenType.SEMICOLON
+}
\ No newline at end of file