code: /*
   * Copyright (c) 2019 the Eclipse Milo Authors
   *
   * This program and the accompanying materials are made
   * available under the terms of the Eclipse Public License 2.0
   * which is available at https://www.eclipse.org/legal/epl-2.0/
   *
   * SPDX-License-Identifier: EPL-2.0
   */
  
  package org.eclipse.milo.opcua.stack.core.channel.messages;
  
  import com.google.common.base.Charsets;
  import com.google.common.base.MoreObjects;
  import io.netty.buffer.ByteBuf;
  import org.eclipse.milo.opcua.stack.core.types.builtin.StatusCode;
  
  public class ErrorMessage {
  
      private final StatusCode error;
      private final String reason;
  
      public ErrorMessage(long error, String reason) {
          this.error = new StatusCode(error);
          this.reason = reason;
      }
  
      public StatusCode getError() {
          return error;
      }
  
      public String getReason() {
          return reason;
      }
  
      @Override
      public String toString() {
  
          return MoreObjects.toStringHelper(this)
              .add("error", error)
              .add("reason", reason)
              .toString();
      }
  
      public static void encode(ErrorMessage message, ByteBuf buffer) {
          buffer.writeIntLE((int) message.getError().getValue());
          encodeString(message.getReason(), buffer);
      }
  
      public static ErrorMessage decode(ByteBuf buffer) {
          return new ErrorMessage(
              buffer.readUnsignedIntLE(),
              decodeString(buffer)
          );
      }
  
      private static void encodeString(String s, ByteBuf buffer) {
          if (s == null) {
              buffer.writeIntLE(-1);
          } else {
              buffer.writeIntLE(s.length());
              buffer.writeBytes(s.getBytes(Charsets.UTF_8));
          }
      }
  
      private static String decodeString(ByteBuf buffer) {
          int length = buffer.readIntLE();
          if (length == -1) {
              return null;
          } else {
              byte[] bs = new byte[length];
              buffer.readBytes(bs);
              return new String(bs, Charsets.UTF_8);
          }
      }
  
  }
  