Javadocs and README.

Change-Id: I10d7cb87ca22475f3f73fb25acd813aa1f8d2bb8

1 files changed, 43 insertions, 0 deletions

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..e482857
--- /dev/null
+++ b/README.md
@@ -0,0 +1,43 @@
+# GVariant for Java
+
+This library provides a [GVariant][] parser in pure Java.
+
+
+## Overview
+
+The two foundational classes are `Value` and `Decoder`.
+
+`Value` is a sum type (sealed interface) that represents a
+[GVariant][] value.  Its subtypes represent the different types of
+values that [GVariant][] supports.
+
+Instances of `Decoder` read a given concrete subtype of `Value` from a
+[ByteBuffer][].  The class also contains factory methods to create
+those instances.
+
+The various subclasses of `Decoder` together implement the [GVariant
+serialization][] specification.
+
+
+## Example
+
+To parse a [GVariant][] value of type `"a(si)"`, which is an array of
+pairs of [String][] and `int`, you can use the following code:
+
+    record ExampleRecord(Value.Str s, Value.Int32 i) {}
+    
+    var decoder =
+      Decoder.ofArray(
+        Decoder.ofStructure(
+          ExampleRecord.class,
+          Decoder.ofStr(StandardCharsets.UTF_8),
+          Decoder.ofInt32().withByteOrder(ByteOrder.LITTLE_ENDIAN)));
+    
+    byte[] bytes = ...;
+    Value.Array<Value.Structure<ExampleRecord>> example = decoder.decode(bytes);
+
+
+[ByteBuffer]: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/nio/ByteBuffer.html
+[GVariant]: https://docs.gtk.org/glib/struct.Variant.html
+[GVariant serialization]: https://people.gnome.org/~desrt/gvariant-serialisation.pdf
+[String]: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/String.html