From 1b5c19b3e42f4549ebb863cd97d2656e833ce516 Mon Sep 17 00:00:00 2001
From: "David A. Madore" <david+git@madore.org>
Date: Tue, 7 Oct 2014 15:42:07 +0200
Subject: Implement .getLastModified() on WeblogServlet.

---
 org/madore/damlengine/WeblogServlet.java | 81 ++++++++++++++++++++++++++++----
 1 file changed, 72 insertions(+), 9 deletions(-)

(limited to 'org/madore/damlengine')

diff --git a/org/madore/damlengine/WeblogServlet.java b/org/madore/damlengine/WeblogServlet.java
index f9d23e3..568a9ec 100644
--- a/org/madore/damlengine/WeblogServlet.java
+++ b/org/madore/damlengine/WeblogServlet.java
@@ -7,6 +7,10 @@ import java.util.Enumeration;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.file.Paths;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
 
 import javax.servlet.ServletConfig;
 import javax.servlet.ServletException;
@@ -30,7 +34,7 @@ import javax.servlet.http.HttpServletResponse;
 
 public class WeblogServlet extends HttpServlet {
 
-    private static final long serialVersionUID = 2014100701L;
+    private static final long serialVersionUID = 2014100703L;
 
     @Override
     public void init(ServletConfig cfg)
@@ -55,22 +59,67 @@ public class WeblogServlet extends HttpServlet {
 	}  }
     }
 
+    static abstract class RequestPath {
+	public static RequestPath parsePath(String pathInfo)
+	    throws ServletException {
+	    Matcher matcher;
+	    if ( pathInfo == null )
+		return new NoSuchPath();
+	    if ( (matcher=Pattern.compile("/(\\d{1,7})").matcher(pathInfo)).matches() ) {
+		final int number;
+		try {
+		    number = Integer.parseInt(matcher.group(1));
+		} catch (NumberFormatException e) {
+		    return new NoSuchPath();
+		}
+		try {
+		    final Connection conn = WeblogDatabaseConnection.getConnection();
+		    final PreparedStatement selSt
+			= conn.prepareStatement("SELECT id , extract(epoch from mdate) FROM entries WHERE id=?");
+		    selSt.setInt(1,number);
+		    final ResultSet selRes = selSt.executeQuery();
+		    if ( selRes.next() ) {
+			int id = selRes.getInt(1);
+			double mdate = selRes.getDouble(2);
+			if ( id != number )
+			    throw new ServletException("this cannot happen");
+			long lastModified = ((long)mdate)*1000;
+			// O'Reilly recommends not using milliseconds part.
+			return new SingleBlogEntryPath(number, lastModified);
+		    } else
+			return new NoSuchPath();
+		} catch (SQLException e) {
+		    throw new ServletException(e);
+		}
+	    }
+	    return new NoSuchPath();
+	}
+    }
+
+    static final class NoSuchPath extends RequestPath { }
+
+    static final class SingleBlogEntryPath extends RequestPath {
+	public int number;
+	public long lastModified;
+	public SingleBlogEntryPath(int number, long lastModified) {
+	    this.number = number;
+	    this.lastModified = lastModified;
+	}
+    }
+
     @Override
     public void doGet(HttpServletRequest request,
                       HttpServletResponse response)
         throws IOException, ServletException
     {
-	Matcher matcher;
-	int number = -1;
-	if ( (matcher=Pattern.compile("/(\\d{1,7})").matcher(request.getPathInfo())).matches() ) {
-	    try {
-		number = Integer.parseInt(matcher.group(1));
-	    } catch (NumberFormatException e) { }
-	}
-	if ( number == -1 ) {
+	final RequestPath rp = RequestPath.parsePath(request.getPathInfo());
+	if ( rp instanceof NoSuchPath ) {
 	    response.sendError(HttpServletResponse.SC_NOT_FOUND);
 	    return;
 	}
+	if ( ! (rp instanceof SingleBlogEntryPath) )
+	    throw new ServletException("this cannot happen");
+	final int number = ((SingleBlogEntryPath)rp).number;
         response.setContentType("text/html; charset=utf-8");
 	response.setCharacterEncoding("UTF-8");
         OutputStream out = response.getOutputStream();
@@ -80,6 +129,20 @@ public class WeblogServlet extends HttpServlet {
 	} catch (Exception e) {
 	    throw new ServletException("exception during WeblogSelect.fullProcess()", e);
 	}
+    }
 
+    @Override
+    public long getLastModified(HttpServletRequest request) {
+	final RequestPath rp;
+	try {
+	    rp = RequestPath.parsePath(request.getPathInfo());
+	} catch (Exception e) {
+	    return -1;
+	}
+	if ( rp instanceof SingleBlogEntryPath ) {
+	    final long lastModified = ((SingleBlogEntryPath)rp).lastModified;
+	    return lastModified;
+	}
+	return -1;
     }
 }
-- 
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