twill-core/src/main/java/org/apache/twill/internal/state/StateNode.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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 org.apache.twill.internal.state;

import com.google.common.util.concurrent.Service;
import org.apache.twill.api.ServiceController;

/**
 *
 */
public final class StateNode {

  private final ServiceController.State state;
  private final String errorMessage;
  private final StackTraceElement[] stackTraces;

  /**
   * Constructs a StateNode with the given state.
   */
  public StateNode(ServiceController.State state) {
    this(state, null, null);
  }

  /**
   * Constructs a StateNode with {@link ServiceController.State#FAILED} caused by the given error.
   */
  public StateNode(Throwable error) {
    this(Service.State.FAILED, error.getMessage(), error.getStackTrace());
  }

  /**
   * Constructs a StateNode with the given state, error and stacktraces.
   * This constructor should only be used by the StateNodeCodec.
   */
  public StateNode(ServiceController.State state, String errorMessage, StackTraceElement[] stackTraces) {
    this.state = state;
    this.errorMessage = errorMessage;
    this.stackTraces = stackTraces;
  }

  public ServiceController.State getState() {
    return state;
  }

  public String getErrorMessage() {
    return errorMessage;
  }

  public StackTraceElement[] getStackTraces() {
    return stackTraces;
  }

  @Override
  public String toString() {
    StringBuilder builder = new StringBuilder("state=").append(state);

    if (errorMessage != null) {
      builder.append("\n").append("error=").append(errorMessage);
    }
    if (stackTraces != null) {
      builder.append("\n");
      for (StackTraceElement stackTrace : stackTraces) {
        builder.append("\tat ").append(stackTrace.toString()).append("\n");
      }
    }
    return builder.toString();
  }

}