manifold.ext.rt.api.ICallHandler Maven / Gradle / Ivy
/*
* Copyright (c) 2020 - Manifold Systems LLC
*
* Licensed 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 manifold.ext.rt.api;
/**
* Facilitates dynamic interface method invocation.
*
* A class can directly or indirectly, via interface extension, implement this
* interface to support dynamic interface method invocation. Any class implementing
* this interface can be cast to any interface. Manifold cooperates
* with the Java compiler to transform calls through an interface to
* ICallHandler.call().
*
* Note unlike a proxy or wrapper a class implementing ICallHandler
* doesn't wrap anything, therefore it doesn't lose its identity in the process
* of making calls.
*
* @see "MapStructExt"
*/
@Structural
public interface ICallHandler
{
/**
* A value resulting from #call() indicating the call could not be dispatched.
*/
Object UNHANDLED = new Object()
{
@Override
public String toString()
{
return "Unhandled";
}
};
/**
* Dispatch a call to an interface method.
*
* @param proxy The proxy instance delegating this call, null if not a proxy
* @param iface The extended interface and owner of the method
* @param name The name of the method
* @param actualName The actual name of the property associated with the method e.g., a Json name that is not a legal Java identifier, can be null
* @param returnType The return type of the method
* @param paramTypes The parameter types of the method
* @param args The arguments from the call site
* @return The result of the method call or UNHANDLED if the method is not dispatched. Null if the method's return type is void.
*/
Object call( Object proxy, Class iface, String name, String actualName, Class returnType, Class[] paramTypes, Object[] args );
}