org.fusesource.restygwt.client.dispatcher.AbstractRetryingCallback.java Source code

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Here is the source code for org.fusesource.restygwt.client.dispatcher.AbstractRetryingCallback.java

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/**
 * Copyright (C) 2009-2010 the original author or authors.
 * See the notice.md file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * 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 org.fusesource.restygwt.client.dispatcher;

import java.util.logging.Logger;

import com.google.gwt.core.client.GWT;
import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.Response;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;

public abstract class AbstractRetryingCallback implements RequestCallback {

    /**
     * Used by RetryingCallback
     * default value is 5
     */
    protected static int numberOfRetries = 5;

    protected static Logger logger = Logger.getLogger(AbstractRetryingCallback.class.getName());

    /**
     * time to wait for reconnect upon failure
     */
    protected int gracePeriod = 1000;

    protected int currentRetryCounter = 0;

    protected final RequestBuilder requestBuilder;
    protected final RequestCallback requestCallback;

    public AbstractRetryingCallback(RequestBuilder requestBuilder, RequestCallback requestCallback) {

        this.requestBuilder = requestBuilder;
        this.requestCallback = requestCallback;
    }

    @Override
    public abstract void onResponseReceived(Request request, Response response);

    @Override
    public void onError(Request request, Throwable exception) {
        handleErrorGracefully();
    }

    public void handleErrorGracefully() {

        // error handling...:
        if (currentRetryCounter < numberOfRetries) {
            GWT.log("error handling in progress...");

            currentRetryCounter++;

            Timer t = new Timer() {

                public void run() {

                    try {
                        requestBuilder.send();
                    } catch (RequestException ex) {
                        logger.severe(ex.getMessage());
                    }
                }
            };

            t.schedule(gracePeriod);

            gracePeriod = gracePeriod * 2;

        } else {
            // Super severe error.
            // reload app or redirect.
            // ===> this breaks the app but that's by intention.
            if (Window.confirm("error")) {

                Window.Location.reload();

            }
        }

    }

}