LwHttp.java

/*
 * Copyright 2013 Hannes Janetzek
 *
 * This program is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * This program 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.oscim.tiling.source;

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

import org.oscim.core.Tile;
import org.oscim.layers.tile.MapTile;

import com.google.gwt.typedarrays.client.Uint8ArrayNative;
import com.google.gwt.typedarrays.shared.Uint8Array;
import com.google.gwt.xhr.client.ReadyStateChangeHandler;
import com.google.gwt.xhr.client.XMLHttpRequest;
import com.google.gwt.xhr.client.XMLHttpRequest.ResponseType;

public class LwHttp implements HttpEngine {
	//static final Logger log = LoggerFactory.getLogger(LwHttp.class);

	private XMLHttpRequest mHttpRequest;

	private ReadyStateChangeHandler mResponseHandler;

	public LwHttp(UrlTileSource tileSource) {
		mTileSource = tileSource;
	}

	static class Buffer extends InputStream {
		Uint8Array mBuffer;
		int mPos;
		int mEnd;

		public Buffer(Uint8Array buf) {
			mBuffer = buf;
			mPos = 0;
			mEnd = buf.byteLength();
		}

		@Override
		public synchronized int read() throws IOException {
			if (mPos < mEnd)
				return mBuffer.get(mPos++);

			return -1;
		}
	}

	public void close() {
		if (mHttpRequest == null)
			return;

		mHttpRequest.abort();
		mHttpRequest = null;
	}

	private UrlTileSource mTileSource;

	public void sendRequest(MapTile tile, final UrlTileDataSource dataSource) {

		String url = mTileSource.getTileUrl(tile);

		mHttpRequest = XMLHttpRequest.create();
		mHttpRequest.open("GET", url);
		mHttpRequest.setResponseType(ResponseType.ArrayBuffer);

		mResponseHandler = new ReadyStateChangeHandler() {

			@Override
			public void onReadyStateChange(XMLHttpRequest xhr) {
				int state = xhr.getReadyState();
				//log.debug(mCurrentUrl + "response " + status + "/" + state);

				if (state == XMLHttpRequest.DONE) {
					if (xhr.getStatus() == 200) {
						Uint8Array buf = Uint8ArrayNative.create(xhr.getResponseArrayBuffer());
						dataSource.process(new Buffer(buf));
					} else {
						dataSource.process(null);
					}
					mHttpRequest = null;
				}
			}
		};

		mHttpRequest.setOnReadyStateChange(mResponseHandler);
		mHttpRequest.send();
	}

	public static class LwHttpFactory implements HttpEngine.Factory {

		@Override
		public HttpEngine create(UrlTileSource tileSource) {
			return new LwHttp(tileSource);
		}
	}

	@Override
	public InputStream read() throws IOException {
		return null;
	}

	@Override
	public void setCache(OutputStream os) {
	}

	@Override
	public boolean requestCompleted(boolean success) {
		//	mHttpRequest.clearOnReadyStateChange();
		//	mHttpRequest = null;
		return true;
	}

	@Override
	public void sendRequest(Tile tile) throws IOException {
	}
}