org.springframework.core.ExceptionDepthComparator Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or 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
*
* https://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.springframework.core;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.List;
import org.springframework.util.Assert;
/**
* Comparator capable of sorting exceptions based on their depth from the thrown exception type.
*
* @author Juergen Hoeller
* @author Arjen Poutsma
* @since 3.0.3
*/
public class ExceptionDepthComparator implements Comparator> {
private final Class targetException;
/**
* Create a new ExceptionDepthComparator for the given exception.
* @param exception the target exception to compare to when sorting by depth
*/
public ExceptionDepthComparator(Throwable exception) {
Assert.notNull(exception, "Target exception must not be null");
this.targetException = exception.getClass();
}
/**
* Create a new ExceptionDepthComparator for the given exception type.
* @param exceptionType the target exception type to compare to when sorting by depth
*/
public ExceptionDepthComparator(Class exceptionType) {
Assert.notNull(exceptionType, "Target exception type must not be null");
this.targetException = exceptionType;
}
@Override
public int compare(Class o1, Class o2) {
int depth1 = getDepth(o1, this.targetException, 0);
int depth2 = getDepth(o2, this.targetException, 0);
return (depth1 - depth2);
}
private int getDepth(Class declaredException, Class exceptionToMatch, int depth) {
if (exceptionToMatch.equals(declaredException)) {
// Found it!
return depth;
}
// If we've gone as far as we can go and haven't found it...
if (exceptionToMatch == Throwable.class) {
return Integer.MAX_VALUE;
}
return getDepth(declaredException, exceptionToMatch.getSuperclass(), depth + 1);
}
/**
* Obtain the closest match from the given exception types for the given target exception.
* @param exceptionTypes the collection of exception types
* @param targetException the target exception to find a match for
* @return the closest matching exception type from the given collection
*/
public static Class findClosestMatch(
Collection> exceptionTypes, Throwable targetException) {
Assert.notEmpty(exceptionTypes, "Exception types must not be empty");
if (exceptionTypes.size() == 1) {
return exceptionTypes.iterator().next();
}
List> handledExceptions = new ArrayList<>(exceptionTypes);
handledExceptions.sort(new ExceptionDepthComparator(targetException));
return handledExceptions.get(0);
}
}