27 lines
1.3 KiB
ReStructuredText
27 lines
1.3 KiB
ReStructuredText
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.. _exception-handling-java:
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Exception Handling
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==================
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Exceptions thrown during route execution bubble up through the route structure to the next enclosing
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:ref:`-handleExceptions-java-` directive or the top of your route structure.
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Similarly to the way that :ref:`rejections-java` are handled the :ref:`-handleExceptions-java-` directive delegates the actual job
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of converting an exception to its argument, an ``ExceptionHandler``.
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An ``ExceptionHandler`` is a partial function, so it can choose which exceptions it would like to handle and
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which not. Unhandled exceptions will simply continue to bubble up in the route structure.
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At the root of the route tree any still unhandled exception will be dealt with by the top-level handler which always
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handles *all* exceptions.
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``Route.seal`` internally wraps its argument route with the :ref:`-handleExceptions-java-` directive in order to "catch" and
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handle any exception.
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So, if you'd like to customize the way certain exceptions are handled you need to write a custom ``ExceptionHandler``.
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Once you have defined your custom ``ExceptionHandler`` you can supply it as argument to the :ref:`-handleExceptions-java-` directive.
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That will apply your handler to the inner route given to that directive.
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Here is an example for wiring up a custom handler via :ref:`-handleExceptions-java-`:
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TODO
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