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/*

 * Copyright 2009 Electronic Business Systems Ltd.

 *

 * This file is part of GSS.

 *

 * GSS is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * GSS is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with GSS.  If not, see <http://www.gnu.org/licenses/>.

 */

package gr.ebs.gss.web.client.rest;

import gr.ebs.gss.web.client.GSS;

import gr.ebs.gss.common.exceptions.ObjectNotFoundException;

import gr.ebs.gss.web.client.rest.resource.FileResource;

import gr.ebs.gss.web.client.rest.resource.FolderResource;

import gr.ebs.gss.web.client.rest.resource.GroupResource;

import gr.ebs.gss.web.client.rest.resource.GroupUserResource;

import gr.ebs.gss.web.client.rest.resource.GroupsResource;

import gr.ebs.gss.web.client.rest.resource.RestResource;

import gr.ebs.gss.web.client.rest.resource.SharedResource;

import gr.ebs.gss.web.client.rest.resource.TrashResource;

import gr.ebs.gss.web.client.rest.resource.UserResource;

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.Response;

/**

 * @author kman

 *

 */

public  abstract class HeadCommand<T extends RestResource> extends RestCommand{

        boolean complete = false;

        T result = null;

        Class<T> aclass;

        private boolean requestSent = false;

        T cached;

        final String path;

        public HeadCommand(Class<T> theclass, String pathToGet, T theCached){

                this(theclass, pathToGet, true, theCached);

        }

        public HeadCommand(Class<T> theClass, String pathToGet, boolean showLoading, T theCached){

                setShowLoadingIndicator(showLoading);

                this.aclass = theClass;

                if(isShowLoadingIndicator())

                        GSS.get().showLoadingIndicator("Getting ",pathToGet);

                if(theClass.equals(FileResource.class))

                        path = pathToGet;

                else

                        path = fixPath(pathToGet);

                this.cached = theCached;

        }

        private void sendRequest(){

                if(requestSent)

                        return;

                requestSent=true;

                RequestBuilder builder = new RequestBuilder(RequestBuilder.HEAD, path);

                if(cached!=null && cached.getLastModifiedSince() != null){

                        GWT.log("ADDING IF MODIFIED HEADERS", null);

                        builder.setHeader("If-Modified-Since", cached.getLastModifiedSince());

                }

                try {

                        handleHeaders(builder, path);

                        builder.sendRequest("", new RestCallback(path) {

                                @Override

                                public Object deserialize(Response response) {

                                        return deserializeResponse(path, response);

                                }

                                @Override

                                public void handleError(Request request, Throwable exception) {

                                        if(exception instanceof RestException)

                                                if(((RestException)exception).getHttpStatusCode() == 304 && cached != null){

                                                        GWT.log("Using cache:"+cached.getUri(), null);

                                                        handleSuccess(cached);

                                                        return;

                                                }

                                        complete = true;

                                        HeadCommand.this.onError(exception);

                                }

                                @Override

                                public void handleSuccess(Object object) {

                                        result = (T) object;

                                        complete = true;

                                }

                        });

                } catch (Exception ex) {

                        complete = true;

                        onError(ex);

                }

        }

        public boolean isComplete() {

                return complete;

        }

        public T getResult(){

                return result;

        }

        @Override

        public boolean execute() {

                if(!requestSent)

                        sendRequest();

                boolean com = isComplete();

                if(com){

                        if(isShowLoadingIndicator())

                                GSS.get().hideLoadingIndicator();

                        if(getResult() != null)

                                onComplete();

                        else

                                onError(new ObjectNotFoundException("Resource Not Found"));

                        return false;

                }

                return true;

        }

        public  Object deserializeResponse(String aPath, Response response){

                RestResource result1 = null;

                if(aclass.equals(FolderResource.class)){

                        result1 = new FolderResource(aPath);

                        result1.createFromJSON(response.getText());

                }

                else if(aclass.equals(FileResource.class)){

                        result1 = new FileResource(aPath);

                        result1.createFromJSON(response.getHeader("X-GSS-Metadata"));

                }

                else if(aclass.equals(GroupsResource.class)){

                        result1 = new GroupsResource(aPath);

                        result1.createFromJSON(response.getText());

                }

                else if(aclass.equals(TrashResource.class)){

                        result1 = new TrashResource(aPath);

                        result1.createFromJSON(response.getText());

                }

                else if(aclass.equals(SharedResource.class)){

                        result1 = new SharedResource(aPath);

                        result1.createFromJSON(response.getText());

                }

                else if(aclass.equals(GroupResource.class)){

                        result1 = new GroupResource(aPath);

                        result1.createFromJSON(response.getText());

                }

                else if(aclass.equals(GroupUserResource.class)){

                        result1 = new GroupUserResource(aPath);

                        result1.createFromJSON(response.getText());

                }

                else if(aclass.equals(UserResource.class)){

                        result1 = new UserResource(aPath);

                        result1.createFromJSON(response.getText());

                }

                return result1;

        }

}