--- /dev/null	2018-06-17 23:18:20.806999507 +0800
+++ new/src/share/classes/jdk/jfr/internal/cmd/StructuredWriter.java	2019-01-29 10:59:53.149160841 +0800
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code 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 General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.internal.cmd;
+
+import java.io.PrintWriter;
+
+abstract class StructuredWriter {
+    private final static String LINE_SEPARATOR = String.format("%n");
+
+    private final PrintWriter out;
+    private final StringBuilder builder = new StringBuilder(4000);
+
+    private char[] indentionArray = new char[0];
+    private int indent = 0;
+    private int column;
+
+    StructuredWriter(PrintWriter p) {
+        out = p;
+    }
+
+    final protected int getColumn() {
+        return column;
+    }
+
+    // Flush to print writer
+    public final void flush() {
+        out.print(builder.toString());
+        builder.setLength(0);
+    }
+
+    final public void printIndent() {
+        builder.append(indentionArray, 0, indent);
+        column += indent;
+    }
+
+    final public void println() {
+        builder.append(LINE_SEPARATOR);
+        column = 0;
+    }
+
+    final public void print(String... texts) {
+        for (String text : texts) {
+            print(text);
+        }
+    }
+
+    final public void printAsString(Object o) {
+        print(String.valueOf(o));
+    }
+
+    final public void print(String text) {
+        builder.append(text);
+        column += text.length();
+    }
+
+    final public void print(char c) {
+        builder.append(c);
+        column++;
+    }
+
+    final public void print(int value) {
+        print(String.valueOf(value));
+    }
+
+    final public void indent() {
+        indent += 2;
+        updateIndent();
+    }
+
+    final public void retract() {
+        indent -= 2;
+        updateIndent();
+    }
+
+    final public void println(String text) {
+        print(text);
+        println();
+    }
+
+    private void updateIndent() {
+        if (indent > indentionArray.length) {
+            indentionArray = new char[indent];
+            for (int i = 0; i < indentionArray.length; i++) {
+                indentionArray[i] = ' ';
+            }
+        }
+    }
+}