goofing around with URLs in java

digressions/Makefile

@@ -1,5 +1,8 @@
 CFLAGS += -g -Wall -Wextra
 
-all: temperatures
+%.class:%.java
+	javac -d $(PWD) $^
+
+all: temperatures URLParts.class
 
 .PHONY: all

digressions/URLParts.java

@@ -0,0 +1,52 @@
+import java.net.URL;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Collections;
+
+/**
+ * A crappy little toy exercise not intended for actual usage.
+ * Given a URL as first argument, prints the component parts on separate lines
+ * all fancy-like.  Also does some silly guessing when there's no port
+ * provided.  Unmazing.
+ */
+public class URLParts {
+    public static final Map<String, Integer> defaultPorts;
+    static {
+        Map<String, Integer> tmpMap = new HashMap<String, Integer>();
+        tmpMap.put("http", 80);
+        tmpMap.put("https", 443);
+        tmpMap.put("file", -1);
+        defaultPorts = Collections.unmodifiableMap(tmpMap);
+    }
+
+    public static void main(String[] args) throws Exception {
+        for (int i = 0; i < args.length; i++) {
+            showParts(new URL(args[i]));
+        }
+    }
+
+    public static void showParts(URL url) {
+        String protocol = url.getProtocol();
+        int port = url.getPort();
+        if (port == -1) {
+            port = getDefaultPortForProtocol(protocol);
+        }
+
+        showPart("protocol", protocol);
+        showPart("host", url.getHost());
+        showPart("port", Integer.toString(port));
+    }
+
+    public static void showPart(String name, String value) {
+        System.out.println(String.format("%s: %s", name, value));
+    }
+
+    public static int getDefaultPortForProtocol(String protocol) {
+        if (protocol == null) {
+            protocol = "http";
+        } else {
+            protocol = protocol.toLowerCase();
+        }
+        return defaultPorts.get(protocol);
+    }
+}