lens-api/src/main/java/org/apache/lens/api/APIResult.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.lens.api;

import javax.xml.bind.annotation.*;

import org.apache.commons.lang.StringUtils;

import lombok.AccessLevel;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;

/**
 * APIResult is the output returned by all the APIs; status-SUCCEEDED or FAILED message- detailed message.
 */
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
/*
 * Instantiates a new API result with values
 */
@AllArgsConstructor
/**
 * Instantiates a new API result.
 */
@NoArgsConstructor(access = AccessLevel.PROTECTED)
public class APIResult extends ToYAMLString {
  /**
   * The status.
   */
  @XmlElement
  @Getter
  private Status status;

  /**
   * The message.
   */
  @XmlElement
  @Getter
  private String message;

  /**
   * API Result status.
   */
  @XmlType
  @XmlEnum
  public enum Status {

    /**
     * The succeeded.
     */
    SUCCEEDED,
    /**
     * The partial.
     */
    PARTIAL,
    /**
     * The failed.
     */
    FAILED
  }

  private static final APIResult SUCCESS = new APIResult(Status.SUCCEEDED, null);

  public static APIResult partial(int actual, int expected) {
    return new APIResult(Status.PARTIAL, actual + " out of " + expected);
  }

  public static APIResult successOrPartialOrFailure(int actual, int expected) {
    return successOrPartialOrFailure(actual, expected, null);
  }

  public static APIResult successOrPartialOrFailure(int actual, int expected, Exception e) {
    if (actual == 0 && expected != 0) {
      return failure(e);
    }
    if (actual < expected) {
      return partial(actual, expected);
    } else {
      return success();
    }
  }

  public static APIResult success() {
    return SUCCESS;
  }
  public static APIResult success(String message) {
    return new APIResult(Status.SUCCEEDED, message);
  }

  public static APIResult failure(Exception e) {
    String cause = extractCause(e);
    return new APIResult(Status.FAILED, cause);
  }

  public static APIResult partial(Exception e) {
    String cause = extractCause(e);
    return new APIResult(Status.PARTIAL, cause);
  }

  private static String extractCause(Throwable e) {
    if (e == null) {
      return null;
    }
    if (e.getCause() != null) {
      String causeMessage = extractCause(e.getCause());
      if (StringUtils.isBlank(e.getMessage())) {
        return causeMessage;
      } else {
        if (e.getMessage().contains(causeMessage)) {
          return causeMessage;
        } else {
          return e.getMessage() + ": " + causeMessage;
        }
      }
    } else {
      return e.getMessage();
    }
  }
}