Synnefo » Pithos

/*

 * Copyright 2011 GRNET S.A. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or

 * without modification, are permitted provided that the following

 * conditions are met:

 *

 *   1. Redistributions of source code must retain the above

 *      copyright notice, this list of conditions and the following

 *      disclaimer.

 *

 *   2. Redistributions in binary form must reproduce the above

 *      copyright notice, this list of conditions and the following

 *      disclaimer in the documentation and/or other materials

 *      provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS

 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED

 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN

 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 *

 * The views and conclusions contained in the software and

 * documentation are those of the authors and should not be

 * interpreted as representing official policies, either expressed

 * or implied, of GRNET S.A.

 */

package gr.grnet.pithos.web.client.rest;

import gr.grnet.pithos.web.client.GSS;

import gr.grnet.pithos.web.client.rest.resource.FileResource;

import gr.grnet.pithos.web.client.rest.resource.FolderResource;

import gr.grnet.pithos.web.client.rest.resource.GroupResource;

import gr.grnet.pithos.web.client.rest.resource.GroupUserResource;

import gr.grnet.pithos.web.client.rest.resource.GroupsResource;

import gr.grnet.pithos.web.client.rest.resource.OtherUserResource;

import gr.grnet.pithos.web.client.rest.resource.OthersResource;

import gr.grnet.pithos.web.client.rest.resource.RestResource;

import gr.grnet.pithos.web.client.rest.resource.SearchResource;

import gr.grnet.pithos.web.client.rest.resource.SharedResource;

import gr.grnet.pithos.web.client.rest.resource.TagsResource;

import gr.grnet.pithos.web.client.rest.resource.TrashResource;

import gr.grnet.pithos.web.client.rest.resource.UploadStatusResource;

import gr.grnet.pithos.web.client.rest.resource.UserResource;

import gr.grnet.pithos.web.client.rest.resource.UserSearchResource;

import java.util.HashMap;

import java.util.Map;

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;

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

        boolean complete = false;

        T result = null;

        Throwable exception = null;

        Class<T> aclass;

        private final String path;

        private String username;

        private boolean requestSent = false;

        T cached;

        private static final long MAX_CACHE_AGE = 1000;

        private static class RequestData {

                public String path;

                public String username;

                public RequestData(String _path, String _username) {

                        path = _path;

                        username = _username;

                }

                @Override

                public int hashCode() {

                        final int prime = 31;

                        int result = 1;

                        result = prime * result + ((path == null) ? 0 : path.hashCode());

                        result = prime * result + ((username == null) ? 0 : username.hashCode());

                        return result;

                }

                @Override

                public boolean equals(Object obj) {

                        if (this == obj)

                                return true;

                        if (obj == null)

                                return false;

                        if (getClass() != obj.getClass())

                                return false;

                        RequestData other = (RequestData) obj;

                        if (path == null) {

                                if (other.path != null)

                                        return false;

                        } else if (!path.equals(other.path))

                                return false;

                        if (username == null) {

                                if (other.username != null)

                                        return false;

                        } else if (!username.equals(other.username))

                                return false;

                        return true;

                }

        }

        private static class ResponseData {

                public long timestamp;

                public Object result;

                public ResponseData(long _timestamp, Object _result) {

                        timestamp = _timestamp;

                        result = _result;

                }

        }

        private static Map<RequestData, ResponseData> cache = new HashMap<RequestData, ResponseData>();

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

                this(theclass, pathToGet, true, theCached);

        }

        public GetCommand(Class<T> theclass, String pathToGet, boolean showLoading, T theCached){

                setShowLoadingIndicator(showLoading);

                if(isShowLoadingIndicator())

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

                this.aclass = theclass;

                if(pathToGet.indexOf("?") != -1)

                        path = pathToGet;

                else

                        path =fixPath(pathToGet);

                this.cached = theCached;

        }

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

                this(theclass, aUsername, pathToGet, true, theCached);

        }

        public GetCommand(Class<T> theclass, String aUsername , String pathToGet, boolean showLoading, T theCached){

                setShowLoadingIndicator(showLoading);

                if(isShowLoadingIndicator())

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

                this.aclass = theclass;

                path = fixPath(pathToGet);

                this.username = aUsername;

                this.cached = theCached;

        }

        private void sendRequest(){

                if(requestSent)

                        return;

                requestSent=true;

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

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

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

                try {

                        if(username == null)

                                handleHeaders(builder, path);

                        else

                                handleHeaders(username, 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) {

                                        result = null;

                                        complete = true;

                                        exception = _exception;

                                        if(_exception instanceof RestException)

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

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

                                                        handleSuccess(cached);

                                                        return;

                                                }

                                }

                                @Override

                                public void handleSuccess(Object object) {

                                        result = (T) object;

                                        complete = true;

                                }

                        });

                } catch (Exception ex) {

                        complete = true;

                        exception = ex;

                }

        }

        public boolean isComplete() {

                return complete;

        }

        public T getResult(){

                return result;

        }

        @Override

        public boolean execute() {

                boolean com = isComplete();

                RequestData key = new RequestData(path, username);

                if (!com) {

                        if (cache.containsKey(key)) {

                                ResponseData resp = cache.get(key);

                                if (resp==null) {

                                        return true;

                                }

                                // Cache hit

                                if (System.currentTimeMillis()-resp.timestamp>MAX_CACHE_AGE) {

                                        // Cache stale, remove

                                        cache.put(key,null);

                                }

                                else {

                                        // Use cache data

                                        if(isShowLoadingIndicator())

                                                GSS.get().hideLoadingIndicator();

                                        if (resp.result instanceof Throwable) {

                                                // Error to be handled

                                                Throwable ex = (Throwable) resp.result;

                                                onError(ex);

                                                return false;

                                        }

                                        result = (T) resp.result;

                                        if (result != null) {

                                                onComplete();

                                        }

                                        complete = true;

                                        return false;

                                }

                        }

                        if(!requestSent) {

                                cache.put(key,null);

                                sendRequest();

                        }

                }

                if(com){

                        if(isShowLoadingIndicator())

                                GSS.get().hideLoadingIndicator();

                        if(getResult() != null) {

                                // Add to cache

                                cache.put(key, new ResponseData(System.currentTimeMillis(), getResult()));

                                onComplete();

                        }

                        else {

                                cache.put(key, new ResponseData(System.currentTimeMillis(), exception));

                                onError(exception);

                        }

                        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(OthersResource.class)){

                        result1 = new OthersResource(aPath);

                        result1.createFromJSON(response.getText());

                }

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

                        result1 = new OtherUserResource(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());

                }

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

                        result1 = new TagsResource(aPath);

                        result1.createFromJSON(response.getText());

                }

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

                        result1 = new SearchResource(aPath);

                        result1.createFromJSON(response.getText());

                }

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

                        result1 = new UserSearchResource(aPath);

                        result1.createFromJSON(response.getText());

                }

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

                        result1 = new UploadStatusResource(aPath);

                        result1.createFromJSON(response.getText());

                }

                return result1;

        }

        public T getCached() {

                return cached;

        }

        public void setCached(T theCached) {

                this.cached = theCached;

        }

        public boolean usedCachedVersion(){

                if(exception !=null && exception instanceof RestException)

                        if(((RestException)exception).getHttpStatusCode() == 304){

                                return true;

                        }

                return false;

        }

}