/*
* 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.publish;
import org.w3c.dom.Document;
import org.apache.isis.applib.annotation.Programmatic;
public interface EventSerializer {
/**
* Combines the {@link EventMetadata metadata} and the {@link EventPayload payload}
* into some serialized form (such as JSON, XML or a string) that can then be published.
*
* <p>
* This method returns an object for maximum flexibility, which is then
* handed off to the {@link PublishingService}. It's important to make sure that the
* publishing service is able to handle the serialized form. Strings are a good
* lowest common denominator, but in some cases are type-safe equivalent, such as a
* {@link Document w3c DOM Document} or a JSON node might be passed instead.
*
* @return a string, some JSON, some XML or some other standard serialized form.
*/
public Object serialize(EventMetadata metadata, EventPayload payload);
/**
* Used as a fallback if no other implementation is defined.
*/
public static class Simple implements EventSerializer {
@Programmatic
@Override
public Object serialize(EventMetadata metadata, EventPayload payload) {
return "PUBLISHED:" +
"\n metadata:" +
"\n id :" + metadata.getId() +
"\n eventType:" + metadata.getEventType() +
"\n user :" + metadata.getUser() +
"\n timestamp:" + metadata.getTimestamp() +
"\n payload:" +
"\n" + payload.toString();
}
}
}