/*
 *  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.tomcat.util;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

Wraps a list of throwables as a single throwable. This is intended to be used
when multiple actions are taken where each may throw an exception but all
actions are taken before any errors are reported.

This class is NOT threadsafe.
/**
 * Wraps a list of throwables as a single throwable. This is intended to be used
 * when multiple actions are taken where each may throw an exception but all
 * actions are taken before any errors are reported.
 * <p>
 * This class is <b>NOT</b> threadsafe.
 */
public class MultiThrowable extends Throwable {

    private static final long serialVersionUID = 1L;

    private List<Throwable> throwables = new ArrayList<>();

    
Add a throwable to the list of wrapped throwables.
Params:
t – The throwable to add/**
     * Add a throwable to the list of wrapped throwables.
     *
     * @param t The throwable to add
     */
    public void add(Throwable t) {
        throwables.add(t);
    }


    
Returns:
A read-only list of the wrapped throwables./**
     * @return A read-only list of the wrapped throwables.
     */
    public List<Throwable> getThrowables() {
        return Collections.unmodifiableList(throwables);
    }


    
Returns:
null if there are no wrapped throwables, the Throwable if there is a single wrapped throwable or the current instance of there are multiple wrapped throwables/**
     * @return {@code null} if there are no wrapped throwables, the Throwable if
     *         there is a single wrapped throwable or the current instance of
     *         there are multiple wrapped throwables
     */
    public Throwable getThrowable() {
        if (size() == 0) {
            return null;
        } else if (size() == 1) {
            return throwables.get(0);
        } else {
            return this;
        }
    }


    
Returns:
The number of throwables currently wrapped by this instance./**
     * @return The number of throwables currently wrapped by this instance.
     */
    public int size() {
        return throwables.size();
    }


    
Overrides the default implementation to provide a concatenation of the
messages associated with each of the wrapped throwables. Note that the
format of the returned String is not guaranteed to be fixed and may
change in a future release.
/**
     * Overrides the default implementation to provide a concatenation of the
     * messages associated with each of the wrapped throwables. Note that the
     * format of the returned String is not guaranteed to be fixed and may
     * change in a future release.
     */
    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append(super.toString());
        sb.append(": ");
        sb.append(size());
        sb.append(" wrapped Throwables: ");
        for (Throwable t : throwables) {
            sb.append("[");
            sb.append(t.getMessage());
            sb.append("]");
        }

        return sb.toString();
    }
}