Line data    Source code

       1             : // Copyright (C) 2021 The Android Open Source Project
       2             : //
       3             : // Licensed under the Apache License, Version 2.0 (the "License");
       4             : // you may not use this file except in compliance with the License.
       5             : // You may obtain a copy of the License at
       6             : //
       7             : // http://www.apache.org/licenses/LICENSE-2.0
       8             : //
       9             : // Unless required by applicable law or agreed to in writing, software
      10             : // distributed under the License is distributed on an "AS IS" BASIS,
      11             : // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             : // See the License for the specific language governing permissions and
      13             : // limitations under the License.
      14             : 
      15             : package com.google.gerrit.server.cancellation;
      16             : 
      17             : import com.google.common.base.Throwables;
      18             : import com.google.gerrit.common.Nullable;
      19             : import java.util.Optional;
      20             : import org.apache.commons.text.WordUtils;
      21             : 
      22             : /** Exception to signal that the current request is cancelled and should be aborted. */
      23             : public class RequestCancelledException extends RuntimeException {
      24             :   private static final long serialVersionUID = 1L;
      25             : 
      26             :   /**
      27             :    * Checks whether the given exception was caused by {@link RequestCancelledException}. If yes, the
      28             :    * {@link RequestCancelledException} is returned. If not, {@link Optional#empty()} is returned.
      29             :    */
      30             :   public static Optional<RequestCancelledException> getFromCausalChain(Throwable e) {
      31           8 :     return Throwables.getCausalChain(e).stream()
      32           8 :         .filter(RequestCancelledException.class::isInstance)
      33           8 :         .map(RequestCancelledException.class::cast)
      34           8 :         .findFirst();
      35             :   }
      36             : 
      37             :   private final RequestStateProvider.Reason cancellationReason;
      38             :   private final Optional<String> cancellationMessage;
      39             : 
      40             :   /**
      41             :    * Create a {@code RequestCancelledException}.
      42             :    *
      43             :    * @param cancellationReason the reason why the request is cancelled
      44             :    * @param cancellationMessage an optional message providing details about the cancellation
      45             :    */
      46             :   public RequestCancelledException(
      47             :       RequestStateProvider.Reason cancellationReason, @Nullable String cancellationMessage) {
      48           3 :     super(createMessage(cancellationReason, cancellationMessage));
      49           3 :     this.cancellationReason = cancellationReason;
      50           3 :     this.cancellationMessage = Optional.ofNullable(cancellationMessage);
      51           3 :   }
      52             : 
      53             :   private static String createMessage(
      54             :       RequestStateProvider.Reason cancellationReason, @Nullable String message) {
      55           3 :     StringBuilder messageBuilder = new StringBuilder();
      56           3 :     messageBuilder.append(String.format("Request cancelled: %s", cancellationReason.name()));
      57           3 :     if (message != null) {
      58           3 :       messageBuilder.append(String.format(" (%s)", message));
      59             :     }
      60           3 :     return messageBuilder.toString();
      61             :   }
      62             : 
      63             :   /** Returns the reason why the request is cancelled. */
      64             :   public RequestStateProvider.Reason getCancellationReason() {
      65           3 :     return cancellationReason;
      66             :   }
      67             : 
      68             :   /** Returns the cancellation reason as a user-readable string. */
      69             :   public String formatCancellationReason() {
      70           2 :     return WordUtils.capitalizeFully(cancellationReason.name().replaceAll("_", " "));
      71             :   }
      72             : 
      73             :   /**
      74             :    * Returns a message providing details about the cancellation, or {@link Optional#empty()} if none
      75             :    * is available.
      76             :    */
      77             :   public Optional<String> getCancellationMessage() {
      78           3 :     return cancellationMessage;
      79             :   }
      80             : }