added simple LRU-based in memory cache

Author: berb

src/de/ioexception/www/server/cache/EntityCacheEntry.java

@@ -0,0 +1,8 @@
+package de.ioexception.www.server.cache;
+
+public interface EntityCacheEntry
+{
+	byte[] getEntity();
+	String getETag();
+	String getContentType();
+}

src/de/ioexception/www/server/cache/impl/EntityCacheEntryImpl.java

@@ -0,0 +1,37 @@
+package de.ioexception.www.server.cache.impl;
+
+import de.ioexception.www.server.cache.EntityCacheEntry;
+
+public class EntityCacheEntryImpl implements EntityCacheEntry
+{
+	private final byte[] entity;
+	private final String eTag;
+	private final String contentType;
+
+	public EntityCacheEntryImpl(byte[] entity, String eTag, String contentType)
+	{
+		super();
+		this.entity = entity;
+		this.eTag = eTag;
+		this.contentType = contentType;
+	}
+
+	@Override
+	public byte[] getEntity()
+	{
+		return entity;
+	}
+
+	@Override
+	public String getETag()
+	{
+		return eTag;
+	}
+
+	@Override
+	public String getContentType()
+	{
+		return contentType;
+	}
+
+}

src/de/ioexception/www/server/impl/BasicHttpServer.java

@@ -8,6 +8,9 @@
 import java.util.concurrent.Executors;
 
 import de.ioexception.www.server.HttpServer;
+import de.ioexception.www.server.cache.Cache;
+import de.ioexception.www.server.cache.EntityCacheEntry;
+import de.ioexception.www.server.cache.impl.LRUCache;
 
 /**
  * A simple HTTP server implementation.
@@ -27,6 +30,8 @@ public class BasicHttpServer implements HttpServer
 	private final ExecutorService workerPool;
 	private final ExecutorService dispatcherService;
 	private final ServerSocket serverSocket;
+	
+	private final Cache<String, EntityCacheEntry> cache = new LRUCache<String, EntityCacheEntry>(100);
 
 
 	/**
@@ -62,7 +67,8 @@ public BasicHttpServer(int port)
 	@Override
 	public void dispatchRequest(Socket socket)
 	{
-		workerPool.submit(new BasicHttpWorker(socket, this));
+//		workerPool.submit(new BasicHttpWorker(socket, this));
+		workerPool.submit(new CachingHttpWorker(socket, this,cache));
 	}
 
 	@Override

src/de/ioexception/www/server/impl/CachingHttpWorker.java

@@ -1,23 +1,62 @@
 package de.ioexception.www.server.impl;
 
 import java.net.Socket;
+import java.util.HashMap;
 
+import de.ioexception.www.Http;
 import de.ioexception.www.http.HttpRequest;
 import de.ioexception.www.http.HttpResponse;
+import de.ioexception.www.http.HttpStatusCode;
+import de.ioexception.www.http.impl.BasicHttpResponse;
+import de.ioexception.www.server.cache.Cache;
+import de.ioexception.www.server.cache.EntityCacheEntry;
+import de.ioexception.www.server.cache.impl.EntityCacheEntryImpl;
 
 public class CachingHttpWorker extends BasicHttpWorker
 {
+	private final Cache<String, EntityCacheEntry> cache;
 
-	public CachingHttpWorker(Socket socket, BasicHttpServer server)
+	public CachingHttpWorker(Socket socket, BasicHttpServer server, Cache<String, EntityCacheEntry> cache)
 	{
 		super(socket, server);
+		this.cache = cache;
 	}
-	
+
 	@Override
 	protected HttpResponse handleRequest(HttpRequest request)
 	{
-		// TODO: add caching support
-		return super.handleRequest(request);
+		EntityCacheEntry cacheEntry = cache.get(request.getRequestUri());
+		
+		if(null == cacheEntry)
+		{
+			HttpResponse response = super.handleRequest(request); 
+			if(response.getStatusCode().equals(HttpStatusCode.OK) && response.getEntity() != null && response.getEntity().length > 0)
+			{
+				EntityCacheEntry entry = new EntityCacheEntryImpl(response.getEntity(), response.getHeaders().get(Http.ETAG), response.getHeaders().get(Http.CONTENT_TYPE));
+				cache.put(request.getRequestUri(), entry);
+			}
+			return response;
+		}
+		else
+		{
+			//TODO check for conditional request
+			BasicHttpResponse response = new BasicHttpResponse();
+			response.setHeaders(new HashMap<String, String>());
+			response.getHeaders().put(Http.SERVER, server.getServerSignature());
+			response.setVersion(request.getHttpVersion());
+			response.getHeaders().put(Http.CONTENT_LENGTH, ""+cacheEntry.getEntity().length);
+			if(null != cacheEntry.getETag())
+			{
+				response.getHeaders().put(Http.ETAG, cacheEntry.getETag());	
+			}
+			if(null != cacheEntry.getContentType())
+			{
+				response.getHeaders().put(Http.CONTENT_TYPE, cacheEntry.getContentType());	
+			}
+			response.setEntity(cacheEntry.getEntity());
+			response.setStatusCode(HttpStatusCode.OK);
+			return response;
+		}
 	}
 
 }