Utilities.java

/*
 * Utilities.java
 *
 * Copyright � 1998-2011 Research In Motion Limited
 * 
 * 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.
 *
 * Note: For the sake of simplicity, this sample application may not leverage
 * resource bundles and resource strings.  However, it is STRONGLY recommended
 * that application developers make use of the localization features available
 * within the BlackBerry development platform to ensure a seamless application
 * experience across a variety of languages and geographies.  For more information
 * on localizing your application, please refer to the BlackBerry Java Development
 * Environment Development Guide associated with this release.
 */

package com.rim.samples.device.browser;

import java.io.IOException;
import java.io.OutputStream;

import javax.microedition.io.Connector;
import javax.microedition.io.HttpConnection;

import net.rim.device.api.io.http.HttpHeaders;
import net.rim.device.api.io.http.HttpProtocolConstants;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.Dialog;
import net.rim.device.api.util.StringUtilities;

/**
 * This class provides common functions required by the
 * BrowserContentManagerDemo and BrowserFieldDemo. This class allows the
 * aforementioned classes to make a connection to a specified url.
 */
public class Utilities {
    /**
     * Connect to a web resource
     * 
     * @param url
     *            The url of the resource
     * @param requestHeaders
     *            The request headers describing the connection to be made
     * @param postData
     *            The data to post to the web resource
     * @return The HttpConnection object representing the connection to the
     *         resource, null if no connection could be made
     */
    public static HttpConnection makeConnection(final String url,
            final HttpHeaders requestHeaders, final byte[] postData) {
        HttpConnection conn = null;
        OutputStream out = null;

        try {
            conn = (HttpConnection) Connector.open(url);

            if (requestHeaders != null) {
                // From
                // http://www.w3.org/Protocols/rfc2616/rfc2616-sec15.html#sec15.1.3
                //
                // Clients SHOULD NOT include a Referer header field in a
                // (non-secure) HTTP
                // request if the referring page was transferred with a secure
                // protocol.
                final String referer =
                        requestHeaders.getPropertyValue("referer");
                boolean sendReferrer = true;

                if (referer != null
                        && StringUtilities.startsWithIgnoreCase(referer,
                                "https:")
                        && !StringUtilities.startsWithIgnoreCase(url, "https:")) {
                    sendReferrer = false;
                }

                int size = requestHeaders.size();
                for (int i = 0; i < size;) {
                    final String header = requestHeaders.getPropertyKey(i);

                    // Remove referer header if needed.
                    if (!sendReferrer && header.equals("referer")) {
                        requestHeaders.removeProperty(i);
                        --size;
                        continue;
                    }

                    final String value = requestHeaders.getPropertyValue(i++);
                    if (value != null) {
                        conn.setRequestProperty(header, value);
                    }
                }
            }

            if (postData == null) {
                conn.setRequestMethod(HttpConnection.GET);
            } else {
                conn.setRequestMethod(HttpConnection.POST);

                conn.setRequestProperty(
                        HttpProtocolConstants.HEADER_CONTENT_LENGTH, String
                                .valueOf(postData.length));

                out = conn.openOutputStream();
                out.write(postData);

            }
        } catch (final IOException e1) {
            errorDialog(e1.toString());
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (final IOException e2) {
                    errorDialog("OutputStream#close() threw " + e2.toString());
                }
            }
        }

        return conn;
    }

    /**
     * Presents a dialog to the user with a given message
     * 
     * @param message
     *            The text to display
     */
    public static void errorDialog(final String message) {
        UiApplication.getUiApplication().invokeLater(new Runnable() {
            public void run() {
                Dialog.alert(message);
            }
        });
    }
}