/*
 * Copyright (c) 2009-2011 Lockheed Martin Corporation
 *
 * 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.eurekastreams.commons.client;

import java.io.Serializable;
import java.util.LinkedList;
import java.util.List;

import com.google.gwt.user.client.rpc.AsyncCallback;

/**
 * Encapsulates a request to perform some action.
 * 
 * @param <T>
 *            specifies the return type
 */
@SuppressWarnings("serial")
public class ActionRequestImpl<T extends Serializable> implements Serializable, ActionRequest<T>
{
    /**
     * Session id.
     */
    private String sessionId;
    /**
     * List of AsyncCallbacks.
     */
    private final List<AsyncCallback<T>> callbackArray = new LinkedList<AsyncCallback<T>>();

    /**
     * Uniquely represents one ServerAction.
     */
    private String actionKey;

    /**
     * The ID of the ActionRequest.
     */
    private Integer id = null;

    /**
     * Returns the ID.
     * 
     * @return the ID
     */
    @Override
    public Integer getId()
    {
        return id;
    }

    /**
     * Sets the ID.
     * 
     * @param inId
     *            the ID
     */
    @Override
    public void setId(final Integer inId)
    {
        this.id = inId;
    }

    /**
     * Parameter to be passed to the ServiceAction.
     */
    private Serializable param = null;

    /**
     * The response generated by the ServerAction.
     */
    private T response = null;

    /**
     * Standard constructor.
     */
    public ActionRequestImpl()
    {

    }

    /**
     * Constructor.
     * 
     * @param inActionKey
     *            - identify the action to load.
     * @param inParam
     *            - paramaters to pass to the action during execution.
     */
    public ActionRequestImpl(final String inActionKey, final Serializable inParam)
    {
        actionKey = inActionKey;
        param = inParam;
    }

    /**
     * Getter.
     * 
     * @return the action key
     */
    @Override
    public String getActionKey()
    {
        return actionKey;
    }

    /**
     * Setter.
     * 
     * @param inActionKey
     *            the action key
     */
    @Override
    public void setActionKey(final String inActionKey)
    {
        this.actionKey = inActionKey;
    }

    /**
     * This getter retrieves the Serializable param for the ActionRequest. This field is only used in the new Action
     * Framework Design.
     * 
     * @return current instance of the Serializable param object for this Request.
     */
    @Override
    public Serializable getParam()
    {
        return param;
    }

    /**
     * This setter sets the Serializable param for this ActionRequest. This field is only used in the new Action
     * Framework Design.
     * 
     * @param inParam
     *            - value to assign to the param of this ActionRequest.
     */
    @Override
    public void setParam(final Serializable inParam)
    {
        param = inParam;
    }

    /**
     * Getter.
     * 
     * @return the ServerAction response
     */
    @Override
    public T getResponse()
    {
        return response;
    }

    /**
     * Setter.
     * 
     * @param inResponse
     *            the ServerAction's response
     */
    @Override
    public void setResponse(final T inResponse)
    {
        this.response = inResponse;
    }

    /**
     * Add callbacks to be executed with executeCallbacks().
     * 
     * @param callback
     *            The callback to add.
     */
    @Override
    public void addCallback(final AsyncCallback<T> callback)
    {
        callbackArray.add(callback);
    }

    /**
     * execute the callbacks that have been added via addCallback().
     * 
     * @param inResponse
     *            The response object.
     */
    @Override
    public void executeCallbacks(final T inResponse)
    {
        for (AsyncCallback<T> callback : callbackArray)
        {
            if (inResponse instanceof Throwable)
            {
                callback.onFailure((Throwable) inResponse);
            }
            else
            {
                callback.onSuccess(inResponse);
            }
        }
    }

    /**
     * Computes equality by the action key and parameters.
     * 
     * see http://java.sun.com/javase/6/docs/api/java/lang/Object.html#equals(java.lang.Object)
     * 
     * type checking warnings are suppressed because the type is not used to determine equality. (And type information
     * is erased at runtime)
     * 
     * @param other
     *            The object to compare with.
     * @return true if object equals this one, false otherwise.
     */
    @Override
    @SuppressWarnings("unchecked")
    public boolean equals(final Object other)
    {

        if (!(other instanceof ActionRequestImpl))
        {
            return false;
        }

        ActionRequestImpl request = (ActionRequestImpl) other;

        if (!actionKey.equals(request.actionKey))
        {
            return false;
        }

        return (param != null && request.param != null) ? param.equals(request.param) : param == request.param;

    }

    /**
     * Recommended to override when overriding equals(). uses actionkey's hashcode.
     * 
     * see http://java.sun.com/javase/6/docs/api/java/lang/Object.html#equals(java.lang.Object)
     * 
     * @return The hashcode.
     */
    @Override
    public int hashCode()
    {
        return actionKey.hashCode();
    }

    /**
     * Gets the session id.
     * 
     * @return the session id.
     */
    @Override
    public String getSessionId()
    {
        return sessionId;
    }

    /**
     * Setter.
     * 
     * @param inSessionId
     *            the session id.
     */
    @Override
    public void setSessionId(final String inSessionId)
    {
        sessionId = inSessionId;
    }

}