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* 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
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* KIND, either express or implied. See the License for the
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package org.apache.cayenne.di.spi;
import java.lang.ref.WeakReference;
import java.lang.reflect.Method;
import org.apache.cayenne.di.DIRuntimeException;
/**
* A class that wraps an annotated method call of an object, passing it DI scope events.
*
* @since 3.1
*/
public class ScopeEventBinding {
private WeakReference<Object> objectReference;
private Method eventHandlerMethod;
private int argWidth;
public ScopeEventBinding(Object object, Method eventHandlerMethod) {
// store weak references for objects to avoid retaining them when they go out of
// scope
this.objectReference = new WeakReference<Object>(object);
this.eventHandlerMethod = eventHandlerMethod;
this.argWidth = eventHandlerMethod.getParameterTypes().length;
// allow public methods of non-public classes to be annotated
eventHandlerMethod.setAccessible(true);
}
public Object getObject() {
return objectReference.get();
}
public boolean onScopeEvent(Object... eventArgs) {
Object object = objectReference.get();
if (object == null) {
return false;
}
try {
eventHandlerMethod.invoke(object, invocationArguments(eventArgs));
}
catch (Exception e) {
throw new DIRuntimeException(
"Error invoking event method %s",
e,
eventHandlerMethod.getName());
}
return true;
}
private Object[] invocationArguments(Object[] eventArgs) {
int eventArgWidth = (eventArgs == null) ? 0 : eventArgs.length;
if (argWidth != eventArgWidth) {
throw new DIRuntimeException(
"Event argument list size (%d) is different "
+ "from the handler method argument list size (%d)",
eventArgWidth,
argWidth);
}
return eventArgs;
}
}