Added a mechanism for retrieving a set of sub-properties (whose keys all

start with a particular prefix) from a configuration object.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@688 6335cc39-0255-0410-8fd6-9bcaacd3b74c

projects/samskivert/src/java/com/samskivert/util/Config.java

@@ -1,5 +1,5 @@
 //
-// $Id: Config.java,v 1.10 2002/03/28 21:50:26 mdb Exp $
+// $Id: Config.java,v 1.11 2002/03/28 22:21:06 mdb Exp $
 //
 // samskivert library - useful routines for java programs
 // Copyright (C) 2001 Michael Bayne
@@ -305,6 +305,37 @@ public class Config
 	return Class.forName(getValue(name, defcname)).newInstance();
     }
 
+    /**
+     * Returns a properties file containing all configuration values that
+     * start with the supplied prefix (plus a trailing "." which will be
+     * added if it doesn't already exist). The keys in the sub-properties
+     * file will have had the prefix stripped off.
+     */
+    public Properties getSubProperties (String prefix)
+    {
+        // slap a trailing dot on if necessary
+        if (!prefix.endsWith(".")) {
+            prefix = prefix + ".";
+        }
+
+        // build the sub-properties
+        Properties props = new Properties();
+        Iterator iter = keys();
+        while (iter.hasNext()) {
+            String key = (String)iter.next();
+            if (!key.startsWith(prefix)) {
+                continue;
+            }
+            String value = getValue(key, (String)null);
+            if (value == null) {
+                continue;
+            }
+            props.put(key.substring(prefix.length()), value);
+        }
+
+        return props;
+    }
+
     /**
      * Returns an iterator that returns all of the configuration keys in
      * this config object.

projects/samskivert/tests/rsrc/util/test.properties

@@ -1,5 +1,5 @@
 #
-# $Id: test.properties,v 1.1 2001/07/12 02:44:34 mdb Exp $
+# $Id: test.properties,v 1.2 2002/03/28 22:21:06 mdb Exp $
 #
 # A test properties file
 
@@ -8,3 +8,6 @@ prop2 = twenty five
 prop3 = 9, 8, 7, 6
 prop4 = one, two, three,, and a half, four
 # prop5 = not defined
+
+sub.sub1 = 5
+sub.sub2 = whee!

projects/samskivert/tests/src/java/com/samskivert/util/ConfigTest.java

@@ -1,9 +1,10 @@
 //
-// $Id: ConfigTest.java,v 1.2 2002/03/28 21:50:27 mdb Exp $
+// $Id: ConfigTest.java,v 1.3 2002/03/28 22:21:06 mdb Exp $
 
 package com.samskivert.util;
 
 import java.util.Iterator;
+import java.util.Properties;
 
 import junit.framework.Test;
 import junit.framework.TestCase;
@@ -43,6 +44,12 @@ public class ConfigTest extends TestCase
 
         Iterator iter = config.keys();
         System.out.println("Keys: " + StringUtil.toString(iter));
+
+        config.setValue("sub.sub3", "three");
+
+        Properties subprops = config.getSubProperties("sub");
+        System.out.println("Sub: " +
+                           StringUtil.toString(subprops.propertyNames()));
     }
 
     public static Test suite ()