org.gss_project.gss.web.client.rest.HeadCommand.java Source code

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Here is the source code for org.gss_project.gss.web.client.rest.HeadCommand.java

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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 org.gss_project.gss.web.client.rest;

import org.gss_project.gss.web.client.GSS;
import org.gss_project.gss.common.exceptions.ObjectNotFoundException;
import org.gss_project.gss.web.client.rest.resource.FileResource;
import org.gss_project.gss.web.client.rest.resource.FolderResource;
import org.gss_project.gss.web.client.rest.resource.GroupResource;
import org.gss_project.gss.web.client.rest.resource.GroupUserResource;
import org.gss_project.gss.web.client.rest.resource.GroupsResource;
import org.gss_project.gss.web.client.rest.resource.RestResource;
import org.gss_project.gss.web.client.rest.resource.SharedResource;
import org.gss_project.gss.web.client.rest.resource.TrashResource;
import org.gss_project.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;
    }
}