AsyncProxy.java

/*
 * Copyright 2012, We The Internet Ltd.
 *
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 *
 * Distributed under a modified BSD License as follow:
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
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 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
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 * Redistributions in binary form must reproduce the above copyright notice,
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 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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package xapi.inject;

import xapi.collect.api.Fifo;
import xapi.except.NotYetImplemented;
import xapi.util.api.ReceivesValue;

import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.GWT.UncaughtExceptionHandler;

/**
 * Base class used for service injections.
 *
 * This class is filled out in the generator layer.
 *
 * @author James X. Nelson (james@wetheinter.net)
 *
 * @param <T> - The type of singleton being injected
 */
public class AsyncProxy <T> {

  protected Fifo<ReceivesValue<T>> pending(){
    throw new NotYetImplemented("You must implement the pending method in generated AsyncProxy instances");
  }
  private int tries;
  public AsyncProxy() {
    tries = 2;
  }

  protected final void accept(ReceivesValue<T> callback){
    if (callback!=null)
      pending().give(callback);
  }

  public final void onFailure(Throwable reason) {
	  reason.printStackTrace();
	  GWT.log("Run async failure", reason);
    if (tries-->0){
      dispatch();
    }else{
      UncaughtExceptionHandler handler = GWT.getUncaughtExceptionHandler();
      if (handler != null)
        handler.onUncaughtException(reason);
    }
  }

  protected final void apply(T value){
    Fifo<ReceivesValue<T>> pending = pending();
    while(!pending.isEmpty())
      pending.take().set(value);
  }

  protected void dispatch(){

  }

}