001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.hadoop.io;
019    
020    import java.io.IOException;
021    import java.util.List;
022    
023    import org.apache.hadoop.classification.InterfaceAudience;
024    import org.apache.hadoop.classification.InterfaceStability;
025    
026    /** Encapsulate a list of {@link IOException} into an {@link IOException} */
027    @InterfaceAudience.Public
028    @InterfaceStability.Stable
029    public class MultipleIOException extends IOException {
030      /** Require by {@link java.io.Serializable} */
031      private static final long serialVersionUID = 1L;
032      
033      private final List<IOException> exceptions;
034      
035      /** Constructor is private, use {@link #createIOException(List)}. */
036      private MultipleIOException(List<IOException> exceptions) {
037        super(exceptions.size() + " exceptions " + exceptions);
038        this.exceptions = exceptions;
039      }
040    
041      /** @return the underlying exceptions */
042      public List<IOException> getExceptions() {return exceptions;}
043    
044      /** A convenient method to create an {@link IOException}. */
045      public static IOException createIOException(List<IOException> exceptions) {
046        if (exceptions == null || exceptions.isEmpty()) {
047          return null;
048        }
049        if (exceptions.size() == 1) {
050          return exceptions.get(0);
051        }
052        return new MultipleIOException(exceptions);
053      }
054    }