/*
* 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.isis.applib.services.exceprecog;
import java.util.Map;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import org.apache.isis.applib.annotation.Programmatic;
/**
* Domain service to (attempt) to recognize certain
* exceptions, and return user-friendly messages instead.
*
* <p>
* Rather than redirecting to a general-purpose error page,
* the message (corresponding to the recognized exception) is rendered
* as a regular validation message.
*
* <p>
* More than one implementation of {@link ExceptionRecognizer} can
* be registered; they will all be consulted (in the order specified in
* <tt>isis.properties</tt>) to determine if they recognize the exception.
* The message returned by the first service recognizing the exception is
* used.
*
* <p>
* The Isis framework also provides a default implementation of this
* service that recognizes any {@link org.apache.isis.applib.RecoverableException}, simply returning
* the exception's {@link org.apache.isis.applib.RecoverableException#getMessage() message}. This
* allows any component or domain object to throw this exception with
* the knowledge that it will be handled appropriately.
*
* <p>
* Initially introduced for the Wicket viewer; check the documentation
* of other viewers to determine whether they also support this service.
*/
public interface ExceptionRecognizer {
/**
* (Attempt to) recognize the exception and return a user-friendly
* message to render instead.
*
* @return user-friendly message to render, or <tt>null</tt> otherwise.
*/
@Programmatic
public String recognize(Throwable ex);
@Programmatic
@PostConstruct
public void init(Map<String, String> properties);
@Programmatic
@PreDestroy
public void shutdown();
}