1 files changed, 75 insertions, 0 deletions
diff --git a/sangria-core/src/main/java/com/tavianator/sangria/core/PrettyTypes.java b/sangria-core/src/main/java/com/tavianator/sangria/core/PrettyTypes.java
new file mode 100644
index 0000000..12721a4
--- /dev/null
+++ b/sangria-core/src/main/java/com/tavianator/sangria/core/PrettyTypes.java
@@ -0,0 +1,75 @@
+/*********************************************************************
+ * Sangria                                                           *
+ * Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.com>      *
+ *                                                                   *
+ * This library is free software. It comes without any warranty, to  *
+ * the extent permitted by applicable law. You can redistribute it   *
+ * and/or modify it under the terms of the Do What The Fuck You Want *
+ * To Public License, Version 2, as published by Sam Hocevar. See    *
+ * the COPYING file or http://www.wtfpl.net/ for more details.       *
+ *********************************************************************/
+
+package com.tavianator.sangria.core;
+
+import com.google.inject.Key;
+
+/**
+ * Utility class for pretty-printing messages containing types.
+ *
+ * @author Tavian Barnes (tavianator@tavianator.com)
+ * @version 1.0
+ * @since 1.0
+ */
+public class PrettyTypes {
+    private PrettyTypes() {
+        // Not for instantiating
+    }
+
+    /**
+     * Format a message.
+     *
+     * @param message The format string.
+     * @param args    The format arguments, possibly containing {@link Class} or {@link Key} instances to be
+     *                pretty-printed.
+     * @return A formatted message.
+     * @see String#format(String, Object...)
+     */
+    public static String format(String message, Object... args) {
+        // This is like Guice's internal Errors.format()
+        Object[] prettyArgs = new Object[args.length];
+        for (int i = 0; i < args.length; ++i) {
+            Object arg = args[i];
+            Object prettyArg;
+
+            if (arg instanceof Class) {
+                prettyArg = format((Class<?>)arg);
+            } else if (arg instanceof Key) {
+                prettyArg = format((Key<?>)arg);
+            } else {
+                prettyArg = arg;
+            }
+
+            prettyArgs[i] = prettyArg;
+        }
+
+        return String.format(message, prettyArgs);
+    }
+
+    private static String format(Class<?> type) {
+        return type.getCanonicalName();
+    }
+
+    private static String format(Key<?> key) {
+        StringBuilder builder = new StringBuilder(key.getTypeLiteral().toString());
+        if (key.getAnnotationType() != null) {
+            builder.append(" annotated with ");
+            if (key.getAnnotation() != null) {
+                builder.append(key.getAnnotation());
+            } else {
+                builder.append("@")
+                        .append(format(key.getAnnotationType()));
+            }
+        }
+        return builder.toString();
+    }
+}