/*
* 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.eventbus;
import java.util.EventObject;
import java.util.Map;
import com.google.common.collect.Maps;
import org.apache.isis.applib.util.ObjectContracts;
public abstract class AbstractUiEvent<S> extends EventObject {
private static final long serialVersionUID = 1L;
//region > constructors
/**
* If used then the framework will set state via (non-API) setters.
*
* <p>
* Because the {@link EventObject} superclass prohibits a null source, a dummy value is temporarily used.
* </p>
*/
public AbstractUiEvent() {
this(null);
}
public AbstractUiEvent(final S source) {
super(sourceElseDummy(source));
}
private static Object sourceElseDummy(final Object source) {
return source != null ? source : new Object();
}
//endregion
//region > source
@Override
@SuppressWarnings("unchecked")
public S getSource() {
return (S)source;
}
/**
* Not API, set by the framework if the no-arg constructor is used.
*/
public void setSource(S source) {
this.source = source;
}
//endregion
//region > userData
/**
* Provides a mechanism to pass data around.
*/
private final Map<Object, Object> userData = Maps.newHashMap();
/**
* Obtain user-data, as set by any other subscribers.
*/
public Object get(Object key) {
return userData.get(key);
}
/**
* Set user-data, for the use of other subscribers.
*/
public void put(Object key, Object value) {
userData.put(key, value);
}
//endregion
//region > toString
@Override
public String toString() {
return ObjectContracts.toString(this, "source");
}
//endregion
}