1 files changed, 78 insertions, 0 deletions
diff --git a/platform/structure-view-api/src/com/intellij/ide/util/treeView/AbstractTreeStructure.java b/platform/structure-view-api/src/com/intellij/ide/util/treeView/AbstractTreeStructure.java
new file mode 100644
index 000000000000..acd6548ff26d
--- /dev/null
+++ b/platform/structure-view-api/src/com/intellij/ide/util/treeView/AbstractTreeStructure.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2000-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.intellij.ide.util.treeView;
+
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.ActionCallback;
+import com.intellij.openapi.util.AsyncResult;
+import com.intellij.psi.PsiDocumentManager;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public abstract class AbstractTreeStructure {
+  public abstract Object getRootElement();
+  public abstract Object[] getChildElements(Object element);
+  @Nullable
+  public abstract Object getParentElement(Object element);
+
+  @NotNull
+  public abstract NodeDescriptor createDescriptor(Object element, NodeDescriptor parentDescriptor);
+
+  public abstract void commit();
+  public abstract boolean hasSomethingToCommit();
+
+  @NotNull
+  public static ActionCallback asyncCommitDocuments(@NotNull Project project) {
+    if (project.isDisposed()) return new ActionCallback.Done();
+    PsiDocumentManager documentManager = PsiDocumentManager.getInstance(project);
+    if (!documentManager.hasUncommitedDocuments()) {
+      return new ActionCallback.Done();
+    }
+    final ActionCallback callback = new ActionCallback();
+    documentManager.performWhenAllCommitted(callback.createSetDoneRunnable());
+    return callback;
+  }
+
+  /**
+   * @return callback which is set to {@link ActionCallback#setDone()} when the tree structure is committed.
+   * By default it just calls {@link #commit()} synchronously but it is desirable to override it
+   * to provide asynchronous commit to the tree structure to make it more responsible.
+   * E.g. when you should commit all documents during the {@link #commit()},
+   * you can use {@link #asyncCommitDocuments(Project)} to do it asynchronously.
+   */
+  @NotNull
+  public ActionCallback asyncCommit() {
+    if (hasSomethingToCommit()) commit();
+    return new ActionCallback.Done();
+  }
+
+  public boolean isToBuildChildrenInBackground(Object element){
+    return false;
+  }
+  
+  public boolean isValid(Object element) {
+    return true;
+  }
+
+  public boolean isAlwaysLeaf(Object element) {
+    return false;
+  }
+
+  public AsyncResult<Object> revalidateElement(Object element) {
+    return new AsyncResult.Done<Object>(element);
+  }
+}
+\ No newline at end of file