/*
* 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.commons.lang3.exception;
import java.util.List;
import java.util.Set;
import org.apache.commons.lang3.tuple.Pair;
/**
* <p>
* An exception that provides an easy and safe way to add contextual information.
* </p><p>
* An exception trace itself is often insufficient to provide rapid diagnosis of the issue.
* Frequently what is needed is a select few pieces of local contextual data.
* Providing this data is tricky however, due to concerns over formatting and nulls.
* </p><p>
* The contexted exception approach allows the exception to be created together with a
* list of context label-value pairs. This additional information is automatically included in
* the message and printed stack trace.
* </p><p>
* An unchecked version of this exception is provided by ContextedRuntimeException.
* </p>
* <p>
* To use this class write code as follows:
* </p>
* <pre>
* try {
* ...
* } catch (Exception e) {
* throw new ContextedException("Error posting account transaction", e)
* .addContextValue("Account Number", accountNumber)
* .addContextValue("Amount Posted", amountPosted)
* .addContextValue("Previous Balance", previousBalance)
* }
* }
* </pre> or improve diagnose data at a higher level:
* <pre>
* try {
* ...
* } catch (ContextedException e) {
* throw e.setContextValue("Transaction Id", transactionId);
* } catch (Exception e) {
* if (e instanceof ExceptionContext) {
* e.setContextValue("Transaction Id", transactionId);
* }
* throw e;
* }
* }
* </pre>
* </p><p>
* The output in a printStacktrace() (which often is written to a log) would look something like the following:
* <pre>
* org.apache.commons.lang3.exception.ContextedException: java.lang.Exception: Error posting account transaction
* Exception Context:
* [1:Account Number=null]
* [2:Amount Posted=100.00]
* [3:Previous Balance=-2.17]
* [4:Transaction Id=94ef1d15-d443-46c4-822b-637f26244899]
*
* ---------------------------------
* at org.apache.commons.lang3.exception.ContextedExceptionTest.testAddValue(ContextedExceptionTest.java:88)
* ..... (rest of trace)
* </pre>
* </p>
*
* @see ContextedRuntimeException
* @since 3.0
*/
public class ContextedException extends Exception implements ExceptionContext {
/** The serialization version. */
private static final long serialVersionUID = 20110706L;
/** The context where the data is stored. */
private final ExceptionContext exceptionContext;
/**
* Instantiates ContextedException without message or cause.
* <p>
* The context information is stored using a default implementation.
*/
public ContextedException() {
super();
exceptionContext = new DefaultExceptionContext();
}
/**
* Instantiates ContextedException with message, but without cause.
* <p>
* The context information is stored using a default implementation.
*
* @param message the exception message, may be null
*/
public ContextedException(String message) {
super(message);
exceptionContext = new DefaultExceptionContext();
}
/**
* Instantiates ContextedException with cause, but without message.
* <p>
* The context information is stored using a default implementation.
*
* @param cause the underlying cause of the exception, may be null
*/
public ContextedException(Throwable cause) {
super(cause);
exceptionContext = new DefaultExceptionContext();
}
/**
* Instantiates ContextedException with cause and message.
* <p>
* The context information is stored using a default implementation.
*
* @param message the exception message, may be null
* @param cause the underlying cause of the exception, may be null
*/
public ContextedException(String message, Throwable cause) {
super(message, cause);
exceptionContext = new DefaultExceptionContext();
}
/**
* Instantiates ContextedException with cause, message, and ExceptionContext.
*
* @param message the exception message, may be null
* @param cause the underlying cause of the exception, may be null
* @param context the context used to store the additional information, null uses default implementation
*/
public ContextedException(String message, Throwable cause, ExceptionContext context) {
super(message, cause);
if (context == null) {
context = new DefaultExceptionContext();
}
exceptionContext = context;
}
//-----------------------------------------------------------------------
/**
* Adds information helpful to a developer in diagnosing and correcting the problem.
* For the information to be meaningful, the value passed should have a reasonable
* toString() implementation.
* Different values can be added with the same label multiple times.
* <p>
* Note: This exception is only serializable if the object added is serializable.
* </p>
*
* @param label a textual label associated with information, {@code null} not recommended
* @param value information needed to understand exception, may be {@code null}
* @return {@code this}, for method chaining, not {@code null}
*/
public ContextedException addContextValue(String label, Object value) {
exceptionContext.addContextValue(label, value);
return this;
}
/**
* Sets information helpful to a developer in diagnosing and correcting the problem.
* For the information to be meaningful, the value passed should have a reasonable
* toString() implementation.
* Any existing values with the same labels are removed before the new one is added.
* <p>
* Note: This exception is only serializable if the object added as value is serializable.
* </p>
*
* @param label a textual label associated with information, {@code null} not recommended
* @param value information needed to understand exception, may be {@code null}
* @return {@code this}, for method chaining, not {@code null}
*/
public ContextedException setContextValue(String label, Object value) {
exceptionContext.setContextValue(label, value);
return this;
}
/**
* {@inheritDoc}
*/
public List<Object> getContextValues(String label) {
return this.exceptionContext.getContextValues(label);
}
/**
* {@inheritDoc}
*/
public Object getFirstContextValue(String label) {
return this.exceptionContext.getFirstContextValue(label);
}
/**
* {@inheritDoc}
*/
public List<Pair<String, Object>> getContextEntries() {
return this.exceptionContext.getContextEntries();
}
/**
* {@inheritDoc}
*/
public Set<String> getContextLabels() {
return exceptionContext.getContextLabels();
}
/**
* Provides the message explaining the exception, including the contextual data.
*
* @see java.lang.Throwable#getMessage()
* @return the message, never null
*/
@Override
public String getMessage(){
return getFormattedExceptionMessage(super.getMessage());
}
/**
* Provides the message explaining the exception without the contextual data.
*
* @see java.lang.Throwable#getMessage()
* @return the message
* @since 3.0.1
*/
public String getRawMessage() {
return super.getMessage();
}
/**
* {@inheritDoc}
*/
public String getFormattedExceptionMessage(String baseMessage) {
return exceptionContext.getFormattedExceptionMessage(baseMessage);
}
}