org.apache.camel.processor.errorhandler

Class DefaultExceptionPolicyStrategy

java.lang.Object

org.apache.camel.processor.errorhandler.DefaultExceptionPolicyStrategy

All Implemented Interfaces:

ExceptionPolicyStrategy

public class DefaultExceptionPolicyStrategy
extends Object
implements ExceptionPolicyStrategy

The default strategy used in Camel to resolve the ExceptionPolicyKey that should handle the thrown exception.

Selection strategy:
This strategy applies the following rules:

• Will walk the exception hierarchy from bottom upwards till the thrown exception, meaning that the most outer caused by is selected first, ending with the thrown exception itself. The method createExceptionIterable(Throwable) provides the Iterator used for the walking.
• The exception type must be configured with an Exception that is an instance of the thrown exception, this is tested using the filter(ExceptionPolicyKey, Class, Throwable) method. By default the filter uses instanceof test.
• If the exception type has exactly the thrown exception then its selected as its an exact match
• Otherwise the type that has an exception that is the closest super of the thrown exception is selected (recurring up the exception hierarchy)

Fine grained matching:
If the ExceptionPolicyKey has a when defined with an expression the type is also matches against the current exchange using the matchesWhen(ExceptionPolicyKey, org.apache.camel.Exchange) method. This can be used to for more fine grained matching, so you can e.g. define multiple sets of exception types with the same exception class(es) but have a predicate attached to select which to select at runtime.

Constructor Summary

Constructors

Constructor and Description
DefaultExceptionPolicyStrategy()

Method Summary

Modifier and Type	Method and Description
protected Iterable<Throwable>	createExceptionIterable(Throwable exception) Strategy method creating the iterator to walk the exception in the order Camel should use for find the ExceptionPolicyKey should be used.
protected boolean	filter(ExceptionPolicyKey type, Class<?> exceptionClass, Throwable exception) Strategy to filter the given type exception class with the thrown exception
ExceptionPolicyKey	getExceptionPolicy(Set<ExceptionPolicyKey> exceptionPolicies, org.apache.camel.Exchange exchange, Throwable exception) Resolves the ExceptionPolicyKey that should handle the thrown exception.
protected boolean	matchesWhen(ExceptionPolicyKey definition, org.apache.camel.Exchange exchange) Strategy method for matching the exception type with the current exchange.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DefaultExceptionPolicyStrategy

public DefaultExceptionPolicyStrategy()

Method Detail

getExceptionPolicy

public ExceptionPolicyKey getExceptionPolicy(Set<ExceptionPolicyKey> exceptionPolicies,
                                             org.apache.camel.Exchange exchange,
                                             Throwable exception)

Description copied from interface: ExceptionPolicyStrategy

Resolves the ExceptionPolicyKey that should handle the thrown exception.

Specified by:

getExceptionPolicy in interface ExceptionPolicyStrategy

Parameters:

exceptionPolicies - the configured exception policies to resolve from

exchange - the exchange

exception - the exception that was thrown

Returns:

the resolved exception type to handle this exception, null if none found.

filter

protected boolean filter(ExceptionPolicyKey type,
                         Class<?> exceptionClass,
                         Throwable exception)

Strategy to filter the given type exception class with the thrown exception

Parameters:

type - the exception type

exceptionClass - the current exception class for testing

exception - the thrown exception

Returns:

true if the to current exception class is a candidate, false to skip it.

matchesWhen

protected boolean matchesWhen(ExceptionPolicyKey definition,
                              org.apache.camel.Exchange exchange)

Strategy method for matching the exception type with the current exchange.

This default implementation will match as:

• Always true if no when predicate on the exception type
• Otherwise the when predicate is matches against the current exchange

Parameters:

definition - the exception definition

exchange - the current Exchange

Returns:

true if matched, false otherwise.

createExceptionIterable

protected Iterable<Throwable> createExceptionIterable(Throwable exception)

Strategy method creating the iterator to walk the exception in the order Camel should use for find the ExceptionPolicyKey should be used.

The default iterator will walk from the bottom upwards (the last caused by going upwards to the exception)

Parameters:

exception - the exception

Returns:

the list to iterate