/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project licenses this file to you 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 io.netty.handler.codec;
  
  import io.netty.util.Signal;
  
  public class DecoderResult {
  
      protected static final Signal SIGNAL_UNFINISHED = Signal.valueOf(DecoderResult.class.getName() + ".UNFINISHED");
      protected static final Signal SIGNAL_SUCCESS = Signal.valueOf(DecoderResult.class.getName() + ".SUCCESS");
  
      public static final DecoderResult UNFINISHED = new DecoderResult(SIGNAL_UNFINISHED);
      public static final DecoderResult SUCCESS = new DecoderResult(SIGNAL_SUCCESS);
  
      public static DecoderResult failure(Throwable cause) {
          if (cause == null) {
              throw new NullPointerException("cause");
          }
          return new DecoderResult(cause);
      }
  
      private final Throwable cause;
  
      protected DecoderResult(Throwable cause) {
          if (cause == null) {
              throw new NullPointerException("cause");
          }
          this.cause = cause;
      }
  
      public boolean isFinished() {
          return cause != SIGNAL_UNFINISHED;
      }
  
      public boolean isSuccess() {
          return cause == SIGNAL_SUCCESS;
      }
  
      public boolean isFailure() {
          return cause != SIGNAL_SUCCESS && cause != SIGNAL_UNFINISHED;
      }
  
      public Throwable cause() {
          if (isFailure()) {
              return cause;
          } else {
              return null;
          }
      }
  
      @Override
      public String toString() {
          if (isFinished()) {
              if (isSuccess()) {
                  return "success";
              }
  
              String cause = cause().toString();
              return new StringBuilder(cause.length() + 17)
                  .append("failure(")
                  .append(cause)
                  .append(')')
                  .toString();
          } else {
              return "unfinished";
          }
      }
  }