From d6989f1e54104d09b8af6d22cf46ea4f6fc5f4dc Mon Sep 17 00:00:00 2001
From: Trygve Laugstøl <trygvis@inamo.no>
Date: Wed, 10 Sep 2014 00:12:30 +0200
Subject: o Initial import of postgresql LISTEN/NOTIFY code.

---
 .../io/trygvis/jz14/demo/KillListenerMain.java     | 58 ++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 src/main/java/io/trygvis/jz14/demo/KillListenerMain.java

(limited to 'src/main/java/io/trygvis/jz14/demo/KillListenerMain.java')

diff --git a/src/main/java/io/trygvis/jz14/demo/KillListenerMain.java b/src/main/java/io/trygvis/jz14/demo/KillListenerMain.java
new file mode 100644
index 0000000..6ea982a
--- /dev/null
+++ b/src/main/java/io/trygvis/jz14/demo/KillListenerMain.java
@@ -0,0 +1,58 @@
+package io.trygvis.jz14.demo;
+
+import io.trygvis.jz14.db.DbListener;
+import org.slf4j.Logger;
+
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Kills all connections from {@link io.trygvis.jz14.demo.ListenerMain}.
+ * <p/>
+ * Note that this is slightly different from a postgresql backend failing, as the client will be told that it was
+ * killed, but the effect in this code is the same.
+ */
+public class KillListenerMain implements DbListener.NewItemCallback {
+    Logger log = getLogger(getClass());
+    Db db = new Db("killer");
+
+    public static void main(String[] args) throws Exception {
+        new KillListenerMain().main();
+    }
+
+    private void main() throws Exception {
+        Connection c = db.getConnection();
+        Statement s = c.createStatement();
+
+        ResultSet rs = s.executeQuery("SELECT pid FROM pg_stat_activity WHERE usename=user AND application_name='listener'");
+        if (!rs.next()) {
+            System.out.println("Couldn't find any listener");
+        } else {
+            List<Integer> pids = new ArrayList<>();
+
+            do {
+                int pid = rs.getInt("pid");
+                pids.add(pid);
+            } while (rs.next());
+
+            for (Integer pid : pids) {
+                System.out.println("Killing " + pid);
+                ResultSet rs2 = s.executeQuery("select pg_terminate_backend(" + pid + ")");
+                rs2.next();
+                System.out.println("rs2.getBoolean(1) = " + rs2.getBoolean(1));
+            }
+        }
+
+        c.close();
+    }
+
+    @Override
+    public void newItem(boolean wasNotified, Iterable<String> parameters) throws Exception {
+        log.info("ListenerMain.newItem: wasNotified={}, parameters={}", wasNotified, parameters);
+    }
+}
-- 
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