Java tutorial
/* * 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 org.springframework.lang.Nullable; /** * Handy class for wrapping checked {@code Exceptions} with a root cause. * * <p>This class is {@code abstract} to force the programmer to extend * the class. {@code getMessage} will include nested exception * information; {@code printStackTrace} and other like methods will * delegate to the wrapped exception, if any. * * <p>The similarity between this class and the {@link NestedRuntimeException} * class is unavoidable, as Java forces these two classes to have different * superclasses (ah, the inflexibility of concrete inheritance!). * * @author Rod Johnson * @author Juergen Hoeller * @see #getMessage * @see #printStackTrace * @see NestedRuntimeException */ public abstract class NestedCheckedException extends Exception { /** Use serialVersionUID from Spring 1.2 for interoperability. */ private static final long serialVersionUID = 7100714597678207546L; static { // Eagerly load the NestedExceptionUtils class to avoid classloader deadlock // issues on OSGi when calling getMessage(). Reported by Don Brown; SPR-5607. NestedExceptionUtils.class.getName(); } /** * Construct a {@code NestedCheckedException} with the specified detail message. * @param msg the detail message */ public NestedCheckedException(String msg) { super(msg); } /** * Construct a {@code NestedCheckedException} with the specified detail message * and nested exception. * @param msg the detail message * @param cause the nested exception */ public NestedCheckedException(@Nullable String msg, @Nullable Throwable cause) { super(msg, cause); } /** * Return the detail message, including the message from the nested exception * if there is one. */ @Override @Nullable public String getMessage() { return NestedExceptionUtils.buildMessage(super.getMessage(), getCause()); } /** * Retrieve the innermost cause of this exception, if any. * @return the innermost exception, or {@code null} if none */ @Nullable public Throwable getRootCause() { return NestedExceptionUtils.getRootCause(this); } /** * Retrieve the most specific cause of this exception, that is, * either the innermost cause (root cause) or this exception itself. * <p>Differs from {@link #getRootCause()} in that it falls back * to the present exception if there is no root cause. * @return the most specific cause (never {@code null}) * @since 2.0.3 */ public Throwable getMostSpecificCause() { Throwable rootCause = getRootCause(); return (rootCause != null ? rootCause : this); } /** * Check whether this exception contains an exception of the given type: * either it is of the given class itself or it contains a nested cause * of the given type. * @param exType the exception type to look for * @return whether there is a nested exception of the specified type */ public boolean contains(@Nullable Class<?> exType) { if (exType == null) { return false; } if (exType.isInstance(this)) { return true; } Throwable cause = getCause(); if (cause == this) { return false; } if (cause instanceof NestedCheckedException) { return ((NestedCheckedException) cause).contains(exType); } else { while (cause != null) { if (exType.isInstance(cause)) { return true; } if (cause.getCause() == cause) { break; } cause = cause.getCause(); } return false; } } }