001/*
002 * Copyright 2015-2020 the original author or authors
003 *
004 * This software is licensed under the Apache License, Version 2.0,
005 * the GNU Lesser General Public License version 2 or later ("LGPL")
006 * and the WTFPL.
007 * You may choose either license to govern your use of this software only
008 * upon the condition that you accept all of the terms of either
009 * the Apache License 2.0, the LGPL 2.1+ or the WTFPL.
010 */
011package org.minidns.util;
012
013import java.io.IOException;
014import java.util.Collection;
015import java.util.Collections;
016import java.util.Iterator;
017import java.util.List;
018
019public final class MultipleIoException extends IOException {
020
021    /**
022     * 
023     */
024    private static final long serialVersionUID = -5932211337552319515L;
025
026    private final List<IOException> ioExceptions;
027
028    private MultipleIoException(List<? extends IOException> ioExceptions) {
029        super(getMessage(ioExceptions));
030        assert !ioExceptions.isEmpty();
031        this.ioExceptions = Collections.unmodifiableList(ioExceptions);
032    }
033
034    public List<IOException> getExceptions() {
035        return ioExceptions;
036    }
037
038    private static String getMessage(Collection<? extends Exception> exceptions) {
039        StringBuilder sb = new StringBuilder();
040        Iterator<? extends Exception> it = exceptions.iterator();
041        while (it.hasNext()) {
042            sb.append(it.next().getMessage());
043            if (it.hasNext()) {
044                sb.append(", ");
045            }
046        }
047        return sb.toString();
048    }
049
050    public static void throwIfRequired(List<? extends IOException> ioExceptions) throws IOException {
051        if (ioExceptions == null || ioExceptions.isEmpty()) {
052            return;
053        }
054        if (ioExceptions.size() == 1) {
055            throw ioExceptions.get(0);
056        }
057        throw new MultipleIoException(ioExceptions);
058    }
059
060    public static IOException toIOException(List<? extends IOException> ioExceptions) {
061        int size = ioExceptions.size();
062        if (size == 1) {
063            return ioExceptions.get(0);
064        } else if (size > 1) {
065            return new MultipleIoException(ioExceptions);
066        }
067        return null;
068    }
069}