add getNetInterfaceConfig() util to get default ethernet config

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

@@ -663,6 +663,46 @@ public class Sigar implements SigarProxy {
         return NetInterfaceConfig.fetch(this, name);
     }
 
+    /**
+     * Get default network interface configuration info.
+     * Iterates getNetInterfaceList(), returning the first
+     * available ethernet interface.
+     * @exception SigarException on failure.
+     */
+    public NetInterfaceConfig getNetInterfaceConfig()
+        throws SigarException {
+
+        String[] interfaces = getNetInterfaceList();
+
+        for (int i=0; i<interfaces.length; i++) {
+            String name = interfaces[i];
+            NetInterfaceConfig ifconfig;
+
+            try {
+                ifconfig = getNetInterfaceConfig(name);
+            } catch (SigarException e) {
+                continue;
+            }
+
+            long flags = ifconfig.getFlags();
+            if ((flags & NetFlags.IFF_UP) <= 0) {
+                continue;
+            }
+            if ((flags & NetFlags.IFF_POINTOPOINT) > 0) {
+                continue;
+            }
+            if ((flags & NetFlags.IFF_LOOPBACK) > 0) {
+                continue;
+            }
+
+            return ifconfig;
+        }
+
+        String msg =
+            "No ethernet interface available";
+        throw new SigarException(msg);
+    }
+
     /**
      * Get network interface stats.
      * @exception SigarException on failure.

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

@@ -118,6 +118,9 @@ public interface SigarProxy {
     public NetInterfaceConfig getNetInterfaceConfig(String name)
         throws SigarException;
 
+    public NetInterfaceConfig getNetInterfaceConfig()
+        throws SigarException;
+
     public NetInterfaceStat getNetInterfaceStat(String name)
         throws SigarException;
 

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

@@ -77,6 +77,8 @@ public class TestNetIf extends SigarTestCase {
         getNetIflist(sigar, false);
         getNetIflist(sigar, false);
         getNetIflist(sigar, true);
+        traceln("Default IP=" +
+                sigar.getNetInterfaceConfig().getAddress());
 
         //XXX somehow manage to trigger a segfault using the
         //1.4.1_02-b06 jdk on linux, no problem with 1.4.2_02-b03