add getNetListenAddress method

bindings/java/src/net/hyperic/sigar/Sigar.java

@@ -637,6 +637,46 @@ public class Sigar implements SigarProxy {
     public native NetConnection[] getNetConnectionList(int flags)
         throws SigarException;
 
+    /**
+     * Get the TCP listen address for the given port.
+     * If the port is not bound to a specific address,
+     * the loopback address will be returned.
+     * If there is not a listener on the given port, null will be returned.
+     */    
+    public String getNetListenAddress(long port)
+        throws SigarException {
+
+        int flags = NetFlags.CONN_SERVER | NetFlags.CONN_TCP;
+
+        NetConnection[] connections =
+            getNetConnectionList(flags);
+
+        for (int i=0; i<connections.length; i++) {
+            NetConnection conn = connections[i];
+
+            if (conn.getState() != NetFlags.TCP_LISTEN) {
+                continue;
+            }
+
+            if (conn.getLocalPort() == port) {
+                if (conn.getLocalAddress().equals(NetFlags.ANY_ADDR)) {
+                    return NetFlags.LOOPBACK_ADDRESS;
+                }
+                else {
+                    return conn.getLocalAddress();
+                }
+            }
+        }
+
+        return null;
+    }
+
+    public String getNetListenAddress(String port)
+        throws SigarException {
+
+        return getNetListenAddress(Long.parseLong(port));
+    }
+
     public NetStat getNetStat()
         throws SigarException {
         return new NetStat(this);

bindings/java/src/net/hyperic/sigar/SigarProxy.java

@@ -129,6 +129,12 @@ public interface SigarProxy {
     public NetConnection[] getNetConnectionList(int flags)
         throws SigarException;
 
+    public String getNetListenAddress(long port)
+        throws SigarException;
+
+    public String getNetListenAddress(String port)
+        throws SigarException;
+
     public NetStat getNetStat() throws SigarException;
 
     public Who[] getWhoList() throws SigarException;

bindings/java/src/net/hyperic/sigar/test/TestNetStat.java

@@ -1,5 +1,7 @@
 package net.hyperic.sigar.test;
 
+import net.hyperic.sigar.NetConnection;
+import net.hyperic.sigar.NetFlags;
 import net.hyperic.sigar.NetStat;
 import net.hyperic.sigar.Sigar;
 import net.hyperic.sigar.SigarNotImplementedException;
@@ -23,5 +25,16 @@ public class TestNetStat extends SigarTestCase {
         assertGtEqZeroTrace("Outbound", netstat.getTcpOutboundTotal());
         assertGtEqZeroTrace("Inbound", netstat.getTcpInboundTotal());
         assertGtEqZeroTrace("Listen", netstat.getTcpListen());
+
+        int flags = NetFlags.CONN_SERVER | NetFlags.CONN_TCP;
+
+        NetConnection[] connections =
+            sigar.getNetConnectionList(flags);
+
+        for (int i=0; i<connections.length; i++) {
+            long port = connections[i].getLocalPort();
+            traceln("Listen " +
+                    sigar.getNetListenAddress(port) + ":" + port);
+        }
     }
 }