svn commit: r517735 - /cocoon/trunk/core/cocoon-servlet-service/cocoon-servlet-service-components/src/main/java/org/apache/cocoon/servletservice/components/ServletSource.java

[gk...@apache.org]

Author: gkossakowski
Date: Tue Mar 13 08:37:58 2007
New Revision: 517735

URL: http://svn.apache.org/viewvc?view=rev&rev=517735
Log:
COCOON-2010: ServletConnection and ServletSource cache-aware.

Modified:
    cocoon/trunk/core/cocoon-servlet-service/cocoon-servlet-service-components/src/main/java/org/apache/cocoon/servletservice/components/ServletSource.java

Modified: cocoon/trunk/core/cocoon-servlet-service/cocoon-servlet-service-components/src/main/java/org/apache/cocoon/servletservice/components/ServletSource.java
URL: http://svn.apache.org/viewvc/cocoon/trunk/core/cocoon-servlet-service/cocoon-servlet-service-components/src/main/java/org/apache/cocoon/servletservice/components/ServletSource.java?view=diff&rev=517735&r1=517734&r2=517735
==============================================================================
--- cocoon/trunk/core/cocoon-servlet-service/cocoon-servlet-service-components/src/main/java/org/apache/cocoon/servletservice/components/ServletSource.java (original)
+++ cocoon/trunk/core/cocoon-servlet-service/cocoon-servlet-service-components/src/main/java/org/apache/cocoon/servletservice/components/ServletSource.java Tue Mar 13 08:37:58 2007
@@ -1,68 +1,158 @@
-/*
- * 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.cocoon.servletservice.components;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-import javax.servlet.ServletException;
-
-import org.apache.cocoon.CascadingIOException;
-import org.apache.cocoon.servletservice.ServletConnection;
-import org.apache.excalibur.source.Source;
-import org.apache.excalibur.source.SourceException;
-import org.apache.excalibur.source.impl.AbstractSource;
-
-/**
- * Implementation of a {@link Source} that gets its content by
- * invoking the Block. 
- *
- * @version $Id$
- */
-public class ServletSource extends AbstractSource {
-    
-    private ServletConnection blockConnection;
-    
-    public ServletSource(String location) throws IOException {
-        // the systemId (returned by getURI()) is by default null
-        // using the block uri is a little bit questionable as it only is valid
-        // whithin the current block, not globally
-        setSystemId(location);
-        this.blockConnection = new ServletConnection(location);
-        this.blockConnection.connect();
-    }
-
-    /* (non-Javadoc)
-     * @see org.apache.excalibur.source.impl.AbstractSource#getInputStream()
-     */
-    public InputStream getInputStream() throws IOException, SourceException {
-        try {
-            return this.blockConnection.getInputStream();
-        } catch (ServletException e) {
-            throw new CascadingIOException(e.getMessage(), e);
-        }
-    }
-
-    /**
-     * Returns true always.
-     * @see org.apache.excalibur.source.Source#exists()
-     */
-    public boolean exists() {
-        return true;
-    }
-
-}
+/*
+ * 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.cocoon.servletservice.components;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.cocoon.CascadingIOException;
+import org.apache.cocoon.servletservice.ServletConnection;
+import org.apache.excalibur.source.Source;
+import org.apache.excalibur.source.SourceException;
+import org.apache.excalibur.source.SourceValidity;
+import org.apache.excalibur.source.impl.AbstractSource;
+
+/**
+ * Implementation of a {@link Source} that gets its content by
+ * invoking the Servlet. 
+ *
+ * @version $Id$
+ */
+public class ServletSource extends AbstractSource {
+    
+    private ServletConnection servletConnection;
+    /**
+     * <p>This validity must be lazy-initialized as there can occur following situations:</p>
+     * <ol>
+     * <li>Source is asked for the validity for the first time so the validity won't be asked if it's valid and 
+     * <code>getInputStream()</code> will be called to get response body. While making request there is no information that could 
+     * be used to set <code>ifModifiedSince</code> property but <i>after</i> fetching response there could be information about 
+     * last modification date that has to be set to the <code>ServletValidity</code> instance.</li>
+     * <li>It's second (or next) time that Source is asked for the validity object so caller has old validity object. Old validity 
+     * object will be asked if it's still valid. New validity object has reference to the {@link ServletConnection} so 
+     * <code>ifModifiedSince</code> property can be set by value pulled from <b>old</b> validity object.</li>
+     * </ol>
+     * 
+     * <p>This two different situations demand lazy-initialization.</p>
+     */
+    private final ServletValidity validity;
+    
+    public ServletSource(String location) throws IOException {
+        // the systemId (returned by getURI()) is by default null
+        // using the block uri is a little bit questionable as it only is valid
+        // whithin the current block, not globally
+        setSystemId(location);
+        this.servletConnection = new ServletConnection(location);
+        this.validity = new ServletValidity(this.servletConnection);
+    }
+
+    /* (non-Javadoc)
+     * @see org.apache.excalibur.source.impl.AbstractSource#getInputStream()
+     */
+    public InputStream getInputStream() throws IOException, SourceException {
+        try {
+        	connect();
+            return this.servletConnection.getInputStream();
+        } catch (ServletException e) {
+            throw new CascadingIOException(e.getMessage(), e);
+        }
+    }
+
+    public long getLastModified() {
+    	try {
+			connect();
+		} catch (Exception e) {
+			return 0;
+		}
+    	return servletConnection.getLastModified();
+	}
+
+	public SourceValidity getValidity() {
+		return this.validity;
+	}
+
+	/**
+     * Returns true always.
+     * @see org.apache.excalibur.source.Source#exists()
+     */
+    public boolean exists() {
+        return true;
+    }
+    
+    private void connect() throws IOException, ServletException {
+    	servletConnection.connect();
+    	//This way it's guaranteed that validity has proper value set
+    	validity.setLastModified(servletConnection.getLastModified());
+    }
+
+    private final class ServletValidity implements SourceValidity {
+    	
+    	/**
+		 * 
+		 */
+		private static final long serialVersionUID = 1793646888814956538L;
+		
+		private transient ServletConnection servletConnection;
+    	private long lastModified;
+
+		public ServletValidity(ServletConnection servletConnection) {
+			this.servletConnection = servletConnection;
+    	}
+
+		/* (non-Javadoc)
+		 * @see org.apache.excalibur.source.SourceValidity#isValid()
+		 */
+		public int isValid() {
+			return 0;
+		}
+
+		/* (non-Javadoc)
+		 * @see org.apache.excalibur.source.SourceValidity#isValid(org.apache.excalibur.source.SourceValidity)
+		 */
+		public int isValid(SourceValidity newValidity) {
+			if (newValidity instanceof ServletValidity) {
+				ServletValidity newServletValidity = (ServletValidity)newValidity;
+				
+				newServletValidity.servletConnection.setIfModifiedSince(this.getLastModified());
+				try {
+					newServletValidity.servletConnection.connect();
+					switch (newServletValidity.servletConnection.getResponseCode()) {
+						case HttpServletResponse.SC_NOT_MODIFIED: return 1;
+						case HttpServletResponse.SC_OK: return -1;
+						default: return 0; 
+					}
+				} catch (Exception e) {
+					return 0;
+				}
+			}
+			return 0;
+		}
+
+		public long getLastModified() {
+			return lastModified;
+		}
+
+		public void setLastModified(long lastModified) {
+			this.lastModified = lastModified;
+		}
+    	
+    }
+
+}