0.10/grid/src/main/java/org/apache/oodt/grid/ProductQueryServlet.java - oodt - Git at Google

 /**
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You 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.
  */

 package org.apache.oodt.grid;

 import java.io.BufferedInputStream;
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.List;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import org.apache.oodt.product.HttpRedirectException;
 import org.apache.oodt.product.LargeProductQueryHandler;
 import org.apache.oodt.product.ProductException;
 import org.apache.oodt.product.QueryHandler;
 import org.apache.oodt.product.Retriever;
 import org.apache.oodt.xmlquery.LargeResult;
 import org.apache.oodt.xmlquery.Result;
 import org.apache.oodt.xmlquery.XMLQuery;


 /**
  * Product query servlet handles product queries.  It always returns the first matching
  * product, if any.  If no handler can provide a product, it returns 404 Not Found.  If
  * there are no query handlers, it returns 404 Not Found.
  *
  */
 public class ProductQueryServlet extends QueryServlet {
 	/** {@inheritDoc} */
 	protected List getServers(Configuration config) {
 		return config.getProductServers();
 	}

 	/** {@inheritDoc} */
 	protected void handleQuery(XMLQuery query, List handlers, HttpServletRequest req, HttpServletResponse res)
 		throws IOException, ServletException {
 		if (handlers.isEmpty()) {
 			res.sendError(HttpServletResponse.SC_NOT_FOUND, "no query handlers available to handle query");
 			return;
 		}

 		try {								       // OK, let's try
 			for (Iterator i = handlers.iterator(); i.hasNext();) {	       // Try each query handler
 				QueryHandler handler = (QueryHandler) i.next();	       // Get the query handler
 				query = handler.query(query);			       // Give it the query
 				if (!query.getResults().isEmpty()) {		       // Did it give any result?
 					Result result = (Result) query.getResults().get(0); // Yes, get the result
 					deliverResult(handler, result, res);	       // And deliver it
 					return;					       // Done!
 				}
 			}
 		} catch (ProductException ex) {
           if (ex instanceof HttpRedirectException) {
             HttpRedirectException hre = (HttpRedirectException) ex;
             res.sendRedirect(hre.getLocation());
           } else {
             res.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, ex.getMessage());
           }
           return;
 		}

 		res.sendError(HttpServletResponse.SC_NOT_FOUND, "no matching products from any query handler");
 	}

 	/**
 	 * Deliver a result.  This streams the product data.
 	 *
 	 * @param handler Which handler produced the result.
 	 * @param result The result.
 	 * @param res The HTTP response to which to send the result data.
 	 * @throws IOException if an error occurs.
 	 */
 	private void deliverResult(QueryHandler handler, Result result, HttpServletResponse res) throws IOException {
 		characterize(handler, result, res);					       // First, describe it using HTTP headers
 		if (result instanceof LargeResult) {				       // Is it a large result?
 			LargeResult lr = (LargeResult) result;			       // Yes, this is gonna take some special work
 			LargeProductQueryHandler lpqh = (LargeProductQueryHandler) handler; // First treat 'em as large
 			ProductRetriever retriever = new ProductRetriever(lpqh);       // Large ones need a retriever
 			lr.setRetriever(retriever);				       // Set the retriever
 		}
 		BufferedInputStream in = null;					       // Start with no input stream
 		try {								       // Then try ...
 			in = new BufferedInputStream(result.getInputStream());	       // To open the input stream
 			byte[] buf = new byte[512];				       // And a byte buffer for data
 			int num;						       // And a place to count data
 			while ((num = in.read(buf)) != -1)			       // While we read
 				res.getOutputStream().write(buf, 0, num);	       // We write
 			res.getOutputStream().flush();				       // Flush to commit response
 		} finally {							       // And finally
 			if (in != null) try {					       // If we opened it
 				in.close();					       // Close it
 			} catch (IOException ignore) {}				       // Ignoring any error during closing
 		}								       // Because come on, it's just closing!
 	}									       // For fsck's sake!

 	/**
 	 * Characterize a result by using HTTP headers.
 	 *
 	 * @param result Result to characterize.
 	 * @param res HTTP response to set headers in.
 	 */
 	private void characterize(QueryHandler handler, Result result, HttpServletResponse res) {
 		String contentType = result.getMimeType();			       // Grab the content type
 		res.setContentType(contentType);				       // Set it
 		long size = result.getSize();					       // Grab the size
 		if (size >= 0)
 			res.addHeader("Content-Length", String.valueOf(size));	       // Don't use setContentLength(int)
 		if (!displayable(contentType))					       // Finally, if a browser can't show it
 			this.suggestFilename(handler, result, res);		       // Then suggest a save-as filename
 	}

 	/**
 	 * Tell if a result is displayable.  This compares its MIME type to a list of MIME
 	 * types commonly displayble by browsers.
 	 *
 	 * @param contentType MIME type.
 	 * @return a <code>boolean</code> value.
 	 */
 	protected static boolean displayable(String contentType) {
 		for (int i = 0; i < DISPLAYABLE_TYPES.length; ++i)		       // For each displayable type
 			if (DISPLAYABLE_TYPES[i].equals(contentType)) return true;     // Does it match?
 		return false;							       // None of 'em do, it's not displayable
 	}

 	/**
 	 * We can suggest a filename (if the client happens to be a browser) using a
 	 * content-disposition header.
 	 *
 	 * @param res a <code>HttpServletResponse</code> value.
 	 */
 	protected void suggestFilename(QueryHandler handler, Result result, HttpServletResponse res) {

 		String resource = result.getResourceID();
 		if (resource == null || resource.length() == 0) resource = "product.dat";

 		// suggest some names based on resource mime type
 		String contentType = res.getContentType();

 		// "zip" mime types
 		if (contentType!=null) {
 			if (contentType.equals("application/x-compressed") ||
 				contentType.equals("application/x-zip-compressed") ||
 				contentType.equals("application/zip") ||
 				contentType.equals("multipart/x-zip") ) {

 				// resource = resource.replaceAll("\\..+",".zip"); // replace extension with .zip
 				resource = "products_" + resource + ".zip";
 			}
 		}

 		// set "Content-disposition" header
 		res.addHeader("Content-disposition", "attachment; filename=\"" + resource + "\"");

 	}

 	/**
 	 * MIME types commonly displayable by browsers.
 	 */
 	private static final String[] DISPLAYABLE_TYPES = {
 		"text/plain", "text/richtext", "text/enriched", "text/tab-separated-values", "text/html", "text/xml", "text/rtf",
 		"message/rfc822", "message/partial", "message/external-body", "message/news", "message/http",
 		"message/delivery-status", "message/disposition-notification", "message/s-http", "application/rtf",
 		"application/pdf", "image/jpeg", "image/gif", "image/tiff", "image/png", "audio/basic", "audio/32kadpcm",
 		"audio/mpeg", "video/mpeg", "video/quicktime"
 	};

 	/**
 	 * Retriever that retrieves product data over a method call boundary to a large
 	 * product query handler.
 	 */
 	private static class ProductRetriever implements Retriever {
 		/**
 		 * Creates a new <code>ProductRetriever</code> instance.
 		 *
 		 * @param handler a <code>LargeProductQueryHandler</code> value.
 		 */
 		public ProductRetriever(LargeProductQueryHandler handler) {
 			this.handler = handler;
 		}

 		/** {@inheritDoc} */
 		public byte[] retrieveChunk(String id, long offset, int len) throws ProductException {
 			return handler.retrieveChunk(id, offset, len);
 		}

 		/** {@inheritDoc} */
 		public void close(String id) throws ProductException {
 			handler.close(id);
 		}

 		/** Handler to use. */
 		private LargeProductQueryHandler handler;
 	}
 }
	/**
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You 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.
	*/

	package org.apache.oodt.grid;

	import java.io.BufferedInputStream;
	import java.io.IOException;
	import java.util.Iterator;
	import java.util.List;
	import javax.servlet.ServletException;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;

	import org.apache.oodt.product.HttpRedirectException;
	import org.apache.oodt.product.LargeProductQueryHandler;
	import org.apache.oodt.product.ProductException;
	import org.apache.oodt.product.QueryHandler;
	import org.apache.oodt.product.Retriever;
	import org.apache.oodt.xmlquery.LargeResult;
	import org.apache.oodt.xmlquery.Result;
	import org.apache.oodt.xmlquery.XMLQuery;


	/**
	* Product query servlet handles product queries. It always returns the first matching
	* product, if any. If no handler can provide a product, it returns 404 Not Found. If
	* there are no query handlers, it returns 404 Not Found.
	*
	*/
	public class ProductQueryServlet extends QueryServlet {
	/** {@inheritDoc} */
	protected List getServers(Configuration config) {
	return config.getProductServers();
	}

	/** {@inheritDoc} */
	protected void handleQuery(XMLQuery query, List handlers, HttpServletRequest req, HttpServletResponse res)
	throws IOException, ServletException {
	if (handlers.isEmpty()) {
	res.sendError(HttpServletResponse.SC_NOT_FOUND, "no query handlers available to handle query");
	return;
	}

	try { // OK, let's try
	for (Iterator i = handlers.iterator(); i.hasNext();) { // Try each query handler
	QueryHandler handler = (QueryHandler) i.next(); // Get the query handler
	query = handler.query(query); // Give it the query
	if (!query.getResults().isEmpty()) { // Did it give any result?
	Result result = (Result) query.getResults().get(0); // Yes, get the result
	deliverResult(handler, result, res); // And deliver it
	return; // Done!
	}
	}
	} catch (ProductException ex) {
	if (ex instanceof HttpRedirectException) {
	HttpRedirectException hre = (HttpRedirectException) ex;
	res.sendRedirect(hre.getLocation());
	} else {
	res.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, ex.getMessage());
	}
	return;
	}

	res.sendError(HttpServletResponse.SC_NOT_FOUND, "no matching products from any query handler");
	}

	/**
	* Deliver a result. This streams the product data.
	*
	* @param handler Which handler produced the result.
	* @param result The result.
	* @param res The HTTP response to which to send the result data.
	* @throws IOException if an error occurs.
	*/
	private void deliverResult(QueryHandler handler, Result result, HttpServletResponse res) throws IOException {
	characterize(handler, result, res); // First, describe it using HTTP headers
	if (result instanceof LargeResult) { // Is it a large result?
	LargeResult lr = (LargeResult) result; // Yes, this is gonna take some special work
	LargeProductQueryHandler lpqh = (LargeProductQueryHandler) handler; // First treat 'em as large
	ProductRetriever retriever = new ProductRetriever(lpqh); // Large ones need a retriever
	lr.setRetriever(retriever); // Set the retriever
	}
	BufferedInputStream in = null; // Start with no input stream
	try { // Then try ...
	in = new BufferedInputStream(result.getInputStream()); // To open the input stream
	byte[] buf = new byte[512]; // And a byte buffer for data
	int num; // And a place to count data
	while ((num = in.read(buf)) != -1) // While we read
	res.getOutputStream().write(buf, 0, num); // We write
	res.getOutputStream().flush(); // Flush to commit response
	} finally { // And finally
	if (in != null) try { // If we opened it
	in.close(); // Close it
	} catch (IOException ignore) {} // Ignoring any error during closing
	} // Because come on, it's just closing!
	} // For fsck's sake!

	/**
	* Characterize a result by using HTTP headers.
	*
	* @param result Result to characterize.
	* @param res HTTP response to set headers in.
	*/
	private void characterize(QueryHandler handler, Result result, HttpServletResponse res) {
	String contentType = result.getMimeType(); // Grab the content type
	res.setContentType(contentType); // Set it
	long size = result.getSize(); // Grab the size
	if (size >= 0)
	res.addHeader("Content-Length", String.valueOf(size)); // Don't use setContentLength(int)
	if (!displayable(contentType)) // Finally, if a browser can't show it
	this.suggestFilename(handler, result, res); // Then suggest a save-as filename
	}

	/**
	* Tell if a result is displayable. This compares its MIME type to a list of MIME
	* types commonly displayble by browsers.
	*
	* @param contentType MIME type.
	* @return a <code>boolean</code> value.
	*/
	protected static boolean displayable(String contentType) {
	for (int i = 0; i < DISPLAYABLE_TYPES.length; ++i) // For each displayable type
	if (DISPLAYABLE_TYPES[i].equals(contentType)) return true; // Does it match?
	return false; // None of 'em do, it's not displayable
	}

	/**
	* We can suggest a filename (if the client happens to be a browser) using a
	* content-disposition header.
	*
	* @param res a <code>HttpServletResponse</code> value.
	*/
	protected void suggestFilename(QueryHandler handler, Result result, HttpServletResponse res) {

	String resource = result.getResourceID();
	if (resource == null \|\| resource.length() == 0) resource = "product.dat";

	// suggest some names based on resource mime type
	String contentType = res.getContentType();

	// "zip" mime types
	if (contentType!=null) {
	if (contentType.equals("application/x-compressed") \|\|
	contentType.equals("application/x-zip-compressed") \|\|
	contentType.equals("application/zip") \|\|
	contentType.equals("multipart/x-zip") ) {

	// resource = resource.replaceAll("\\..+",".zip"); // replace extension with .zip
	resource = "products_" + resource + ".zip";
	}
	}

	// set "Content-disposition" header
	res.addHeader("Content-disposition", "attachment; filename=\"" + resource + "\"");

	}

	/**
	* MIME types commonly displayable by browsers.
	*/
	private static final String[] DISPLAYABLE_TYPES = {
	"text/plain", "text/richtext", "text/enriched", "text/tab-separated-values", "text/html", "text/xml", "text/rtf",
	"message/rfc822", "message/partial", "message/external-body", "message/news", "message/http",
	"message/delivery-status", "message/disposition-notification", "message/s-http", "application/rtf",
	"application/pdf", "image/jpeg", "image/gif", "image/tiff", "image/png", "audio/basic", "audio/32kadpcm",
	"audio/mpeg", "video/mpeg", "video/quicktime"
	};

	/**
	* Retriever that retrieves product data over a method call boundary to a large
	* product query handler.
	*/
	private static class ProductRetriever implements Retriever {
	/**
	* Creates a new <code>ProductRetriever</code> instance.
	*
	* @param handler a <code>LargeProductQueryHandler</code> value.
	*/
	public ProductRetriever(LargeProductQueryHandler handler) {
	this.handler = handler;
	}

	/** {@inheritDoc} */
	public byte[] retrieveChunk(String id, long offset, int len) throws ProductException {
	return handler.retrieveChunk(id, offset, len);
	}

	/** {@inheritDoc} */
	public void close(String id) throws ProductException {
	handler.close(id);
	}

	/** Handler to use. */
	private LargeProductQueryHandler handler;
	}
	}