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/*
* Copyright (C) 2009 The Guava Authors
*
* Licensed 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 com.google.common.testing;
import com.google.common.annotations.GwtCompatible;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
/**
* An {@link ClusterException} is a data structure that allows for some code to "throw multiple
* exceptions", or something close to it. The prototypical code that calls for this class is
* presented below:
*
* <pre>
* void runManyThings({@literal List<ThingToRun>} thingsToRun) {
* for (ThingToRun thingToRun : thingsToRun) {
* thingToRun.run(); // say this may throw an exception, but you want to
* // always run all thingsToRun
* }
* }
* </pre>
*
* <p>This is what the code would become:
*
* <pre>
* void runManyThings({@literal List<ThingToRun>} thingsToRun) {
* {@literal List<Exception>} exceptions = Lists.newArrayList();
* for (ThingToRun thingToRun : thingsToRun) {
* try {
* thingToRun.run();
* } catch (Exception e) {
* exceptions.add(e);
* }
* }
* if (exceptions.size() > 0) {
* throw ClusterException.create(exceptions);
* }
* }
* </pre>
*
* <p>See semantic details at {@link #create(Collection)}.
*
* @author Luiz-Otavio Zorzella
*/
@GwtCompatible
final class ClusterException extends RuntimeException {
public final Collection<? extends Throwable> exceptions;
private ClusterException(Collection<? extends Throwable> exceptions) {
super(
exceptions.size() + " exceptions were thrown. The first exception is listed as a cause.",
exceptions.iterator().next());
ArrayList<Throwable> temp = new ArrayList<>(exceptions);
this.exceptions = Collections.unmodifiableCollection(temp);
}
/** @see #create(Collection) */
public static RuntimeException create(Throwable... exceptions) {
ArrayList<Throwable> temp = new ArrayList<>(Arrays.asList(exceptions));
return create(temp);
}
/**
* Given a collection of exceptions, returns a {@link RuntimeException}, with the following rules:
*
* <ul>
* <li>If {@code exceptions} has a single exception and that exception is a {@link
* RuntimeException}, return it
* <li>If {@code exceptions} has a single exceptions and that exceptions is <em>not</em> a
* {@link RuntimeException}, return a simple {@code RuntimeException} that wraps it
* <li>Otherwise, return an instance of {@link ClusterException} that wraps the first exception
* in the {@code exceptions} collection.
* </ul>
*
* <p>Though this method takes any {@link Collection}, it often makes most sense to pass a {@link
* java.util.List} or some other collection that preserves the order in which the exceptions got
* added.
*
* @throws NullPointerException if {@code exceptions} is null
* @throws IllegalArgumentException if {@code exceptions} is empty
*/
public static RuntimeException create(Collection<? extends Throwable> exceptions) {
if (exceptions.size() == 0) {
throw new IllegalArgumentException("Can't create an ExceptionCollection with no exceptions");
}
if (exceptions.size() == 1) {
Throwable temp = exceptions.iterator().next();
if (temp instanceof RuntimeException) {
return (RuntimeException) temp;
} else {
return new RuntimeException(temp);
}
}
return new ClusterException(exceptions);
}
}
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