From: Jean-Christophe Beaupré <jcbrinfo@users.noreply.github.com>
Date: Sat, 20 Dec 2014 02:43:11 +0000 (-0500)
Subject: progression: Add an API for progression tracking.
X-Git-Tag: v0.7.1~38^2~10
X-Git-Url: http://nitlanguage.org

progression: Add an API for progression tracking.

Signed-off-by: Jean-Christophe Beaupré <jcbrinfo@users.noreply.github.com>
---

diff --git a/lib/progression.nit b/lib/progression.nit
new file mode 100644
index 0000000..b5d7f96
--- /dev/null
+++ b/lib/progression.nit
@@ -0,0 +1,68 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# This file is free software, which comes along with NIT. This software is
+# distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+# without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE. You can modify it is you want, provided this header
+# is kept unaltered, and a notification of the changes is added.
+# You are allowed to redistribute it and sell it, alone or is a part of
+# another product.
+
+# Event-based interface to track the progression of an operation.
+module progression
+
+# An operation that is trackable using a `ProgressionListener`.
+abstract class Trackable
+
+	# Listen to the progression of the operation.
+	var progression_listeners: SimpleCollection[ProgressionListener] =
+			new Array[ProgressionListener]
+
+	# Notice the registered `ProgessionListener` that the operation started.
+	protected fun fire_started do
+		for l in progression_listeners do
+			l.started
+			l.progressed(0)
+		end
+	end
+
+	# Notice the registered `ProgessionListener` that the operation progressed.
+	#
+	# Parameter:
+	#
+	# * `done_part`: Indicates what is done.
+	# * `total`: Indicates what need to be done, `done_part` included.
+	protected fun fire_progressed(done_part: Int, total: Int) do
+		for l in progression_listeners do
+			l.progressed(done_part * l.progression_max / total)
+		end
+	end
+
+	# Notice the registered `ProgessionListener` that the operation is done.
+	protected fun fire_done do
+		for l in progression_listeners do
+			l.progressed(l.progression_max)
+			l.done
+		end
+	end
+end
+
+# Listens to the progression of a possibly long-running operation.
+interface ProgressionListener
+	# The number that represents a completed operation.
+	fun progression_max: Int do return 100
+
+	# The operation started.
+	fun started do end
+
+	# The operation progressed.
+	#
+	# Parameter:
+	#
+	# * `progression`: Indicator of the progession, between `0` and
+	# `progression_max`.
+	fun progressed(progression: Int) do end
+
+	# The operation is done.
+	fun done do end
+end