From c40c0bdf344727c8ea583c465bebd542e63ffc1d Mon Sep 17 00:00:00 2001
From: Jakub Skoczen <jakub@indexdata.dk>
Date: Wed, 24 Feb 2010 15:43:12 +0100
Subject: [PATCH] Add connection pool.

---
 examples/zgate/pom.xml                             |   10 +-
 .../java/com/indexdata/zgate/ZgateServlet.java     |  104 ++++++++++++++++++--
 2 files changed, 105 insertions(+), 9 deletions(-)

diff --git a/examples/zgate/pom.xml b/examples/zgate/pom.xml
index 9a22c04..a1d1487 100644
--- a/examples/zgate/pom.xml
+++ b/examples/zgate/pom.xml
@@ -36,7 +36,13 @@
       <version>3.8.1</version>
       <scope>test</scope>
     </dependency>
-    
+    <dependency>
+      <groupId>commons-pool</groupId>
+      <artifactId>commons-pool</artifactId>
+      <version>1.5.4</version>
+      <type>jar</type>
+      <scope>compile</scope>
+    </dependency>
   </dependencies>
   <build>
     <plugins>
@@ -53,3 +59,5 @@
     <finalName>zgate</finalName>
   </build>
 </project>
+
+
diff --git a/examples/zgate/src/main/java/com/indexdata/zgate/ZgateServlet.java b/examples/zgate/src/main/java/com/indexdata/zgate/ZgateServlet.java
index 13b1a07..459accf 100644
--- a/examples/zgate/src/main/java/com/indexdata/zgate/ZgateServlet.java
+++ b/examples/zgate/src/main/java/com/indexdata/zgate/ZgateServlet.java
@@ -6,7 +6,6 @@
 package com.indexdata.zgate;
 
 import java.io.IOException;
-import java.io.PrintWriter;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
@@ -15,7 +14,11 @@ import javax.servlet.http.HttpServletResponse;
 import org.yaz4j.Connection;
 import org.yaz4j.Record;
 import org.yaz4j.ResultSet;
-import org.yaz4j.exception.ZoomException;
+
+import org.apache.commons.pool.KeyedObjectPool;
+import org.apache.commons.pool.BaseKeyedPoolableObjectFactory;
+import org.apache.commons.pool.impl.GenericKeyedObjectPool;
+
 
 /**
  *
@@ -23,6 +26,83 @@ import org.yaz4j.exception.ZoomException;
  */
 public class ZgateServlet extends HttpServlet {
 
+  private static class ConnKey {
+    private String host;
+    private int port;
+    private String dbname;
+    
+    public ConnKey(String host, int port, String dbname) {
+      this.host = host;
+      this.port = port;
+      this.dbname = dbname;
+    }
+
+    public static ConnKey fromZurl(String zurl) {
+      int colPos = zurl.lastIndexOf(":");
+      int slashPos = zurl.lastIndexOf("/");
+      String host = zurl.substring(0, colPos);
+      int port = Integer.parseInt(zurl.substring(colPos+1, slashPos));
+      String dbname = zurl.substring(slashPos+1);
+      return new ConnKey(host, port, dbname);
+    }
+
+    public String getHost() {
+      return host;
+    }
+
+    public int getPort() {
+      return port;
+    }
+
+    public String getDbname() {
+      return dbname;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+      if (!(obj instanceof ConnKey)) return false;
+      ConnKey other = (ConnKey) obj;
+      return (host.equals(other.host) && port == other.port
+        && dbname.equals(other.dbname));
+    }
+
+    @Override
+    public int hashCode() {
+      int hash = 7;
+      hash = 59 * hash + (this.host != null ? this.host.hashCode() : 0);
+      hash = 59 * hash + this.port;
+      hash = 59 * hash + (this.dbname != null ? this.dbname.hashCode() : 0);
+      return hash;
+    }
+
+    @Override
+    public String toString() {
+      return host + ":" + port + "/" + dbname;
+    }    
+  }
+
+  private class ConnectionMaker extends BaseKeyedPoolableObjectFactory {
+    @Override
+    public Object makeObject(Object key) throws Exception {
+      ConnKey ck = (ConnKey) key;
+      return new Connection(ck.toString(), 0);
+    }
+
+    @Override
+    public void activateObject(Object key, Object obj) throws Exception {
+      ((Connection) obj).connect();
+    }
+
+
+    @Override
+    public void destroyObject(Object key, Object obj) throws Exception {
+      ((Connection) obj).close();
+    }
+  }
+
+  private KeyedObjectPool pool = new GenericKeyedObjectPool(new ConnectionMaker());
+
+
   @Override
   public void init() throws ServletException {
     System.out.println("Zeta: java.library.path=" + System.getProperty("java.library.path"));
@@ -61,10 +141,13 @@ public class ZgateServlet extends HttpServlet {
     response.getWriter().println("maxrecs: " + maxrecs);
     response.getWriter().println();
 
-    Connection con = new Connection(zurl, 0);
-    con.setSyntax(syntax);
+    ConnKey ckey = null;
+    Connection con = null;
     try {
-      con.connect();
+      ckey = ConnKey.fromZurl(zurl);
+      System.out.println("Connection key is" + ckey);
+      con = (Connection) pool.borrowObject(ckey);
+      con.setSyntax(syntax);
       ResultSet set = con.search(query, Connection.QueryType.PrefixQuery);
       response.getWriter().println("Showing " + maxrecs + " of " +set.getSize());
       response.getWriter().println();
@@ -72,10 +155,15 @@ public class ZgateServlet extends HttpServlet {
         Record rec = set.getRecord(i);
         response.getWriter().print(rec.render());
       }
-    } catch (ZoomException ze) {
-      throw new ServletException(ze);
+    } catch (Exception e) {
+      throw new ServletException(e);
     } finally {
-      con.close();
+      try {
+        if (ckey != null && con != null)
+          pool.returnObject(ckey, con);
+      } catch (Exception e) {
+        throw new ServletException(e);
+      }
     }
   }
 
-- 
1.7.10.4