IJMP-1469: make methods for access to node maps synchronous

src/main/kotlin/eu/ibagroup/formainframe/explorer/ui/CommonExplorerTreeStructure.kt

@@ -14,8 +14,10 @@ import com.intellij.openapi.project.Project
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.util.SmartList
 import eu.ibagroup.formainframe.explorer.Explorer
-import java.util.*
-import java.util.concurrent.ConcurrentLinkedQueue
+import java.util.LinkedList
+import java.util.WeakHashMap
+import java.util.concurrent.locks.ReentrantLock
+import kotlin.concurrent.withLock
 
 private val PROVIDERS = SmartList(FileExplorerTreeStructureProvider())
 
@@ -31,46 +33,51 @@ class CommonExplorerTreeStructure<Expl : Explorer<*, *>>(
   private val rootNodeProvider: (explorer: Expl, project: Project, treeStructure: ExplorerTreeStructureBase) -> ExplorerTreeNode<*, *>
 ) : ExplorerTreeStructureBase(explorer, project) {
 
-  private val valueToNodeMap = Collections.synchronizedMap(
-    WeakHashMap<Any, ConcurrentLinkedQueue<ExplorerTreeNode<*, *>>>()
-  )
-  private val fileToNodeMap = Collections.synchronizedMap(
-    WeakHashMap<VirtualFile, ConcurrentLinkedQueue<ExplorerTreeNode<*, *>>>()
-  )
+  private val lock = ReentrantLock()
+
+  private val valueToNodeMap = WeakHashMap<Any, MutableCollection<ExplorerTreeNode<*, *>>>()
+  private val fileToNodeMap = WeakHashMap<VirtualFile, MutableCollection<ExplorerTreeNode<*, *>>>()
 
   /**
-   * Put the node in the value to node map queue and the file to node map queue if the virtual file is present for the node
+   * Put the node in the value to node map list and the file to node map list if the virtual file is present for the node
    * @param node the node to be registered
    */
   override fun registerNode(node: ExplorerTreeNode<*, *>) {
-    valueToNodeMap.getOrPut(node.value) { ConcurrentLinkedQueue() }.add(node)
-    val file = node.virtualFile ?: return
-    fileToNodeMap.getOrPut(file) { ConcurrentLinkedQueue() }.add(node)
+    lock.withLock {
+      valueToNodeMap.getOrPut(node.value) { LinkedList() }.add(node)
+      node.virtualFile?.let { fileToNodeMap.getOrPut(it) { LinkedList() }.add(node) }
+    }
   }
 
   /**
-   * Get the nodes queue from value to node map by the provided value. Empty set will be returned if the queue is not found
-   * @param value the value to get the queue by
+   * Get the nodes list from value to node map by the provided value. Empty list will be returned if the list is not found
+   * @param value the value to get the list by
    */
   @Suppress("UNCHECKED_CAST")
   override fun <V : Any> findByValue(value: V): Collection<ExplorerTreeNode<*, V>> {
-    return valueToNodeMap[value] as Collection<ExplorerTreeNode<*, V>>? ?: emptySet()
+    return lock.withLock {
+      valueToNodeMap[value] as Collection<ExplorerTreeNode<*, V>>? ?: emptyList()
+    }
   }
 
   /**
-   * Search for the values in all the value to node map queues by predicate
+   * Search for the values in all the value to node map lists by predicate
    * @param predicate the predicate to filter by
    */
   override fun findByPredicate(predicate: (ExplorerTreeNode<*, *>) -> Boolean): Collection<ExplorerTreeNode<*, *>> {
-    return valueToNodeMap.values.flatten().filter(predicate)
+    return lock.withLock {
+      valueToNodeMap.values.flatten().filter(predicate)
+    }
   }
 
   /**
-   * Get the nodes queue from file to node map by the provided value. Empty set will be returned if the queue is not found
-   * @param file the virtual file to get the queue by
+   * Get the nodes list from file to node map by the provided value. Empty list will be returned if the list is not found
+   * @param file the virtual file to get the list by
    */
   override fun findByVirtualFile(file: VirtualFile): Collection<ExplorerTreeNode<*, *>> {
-    return fileToNodeMap[file] ?: emptySet()
+    return lock.withLock {
+      fileToNodeMap[file] ?: emptyList()
+    }
   }
 
   private val root by lazy { rootNodeProvider(explorer, project, this) }