Add a little script to show comme use of the databases.

spec/various-common-usages.cr

@@ -0,0 +1,79 @@
+require "./db-cars.cr"
+
+rootdb = "/tmp/test-db"
+
+db = DODB::Storage::Cached(Car).new rootdb
+#db = DODB::Storage::Common(Car).new rootdb, 2
+index_name     = db.new_index     "name",     &.name
+index_color    = db.new_partition "color",    &.color
+index_keywords = db.new_tags      "keywords", &.keywords
+
+car0 = Car.new "Corvet-0", "red",    ["shiny"]
+car1 = Car.new "Corvet-1", "red",    ["slow", "expensive"]
+car2 = Car.new "Corvet-2", "blue",   ["fast", "elegant"]
+car3 = Car.new "Corvet-3", "violet", ["expensive"]
+
+db << car0
+db << car1
+db << car2
+db << car3
+
+# Get a car from stored data based on its name.
+if (c = index_name.get?("Corvet-2")) == car2
+	puts "We found the Corvet-2: #{c}"
+else
+	puts "We didn't find the Corvet-2!!!"
+end
+
+# Get a car from stored data based on a keyword.
+if c = index_keywords.get?("elegant")
+	puts "We found the elegant car: #{c}"
+else
+	puts "We didn't find the elegant car!!!"
+end
+
+# All cached entries are dropped.
+# WARNING: the Storage::Cached database don't read anything on the filesystem and relies entirely
+#          on cached values. Therefore, clearing the caches means the database won't answer any request
+#          with the proper values. The content has to be read again through a reindex_everything! for example.
+#db.clear_cache!
+
+db = DODB::Storage::Cached(Car).new rootdb
+index_name     = db.new_index     "name",     &.name
+index_color    = db.new_partition "color",    &.color
+index_keywords = db.new_tags      "keywords", &.keywords
+db.reindex_everything!
+
+# Get a car from stored data based on its color.
+if index_color.get?("violet").size == 1
+	puts "We found the violet car"
+else
+	puts "We didn't find the violet car!!!"
+end
+
+# Get a car from stored data based on a keyword.
+list_of_cars = index_keywords.get?("expensive")
+if ! list_of_cars.nil? && list_of_cars.size > 0
+	puts "We found the expensive cars:"
+	list_of_cars.each { |car| puts "- #{car}" }
+else
+	puts "We didn't find the expensive car!!!"
+end
+
+# Loop over entries, filling up the cache for Storage.
+total_values = 0
+	db.each_with_key do |v, k|
+	total_values += 1
+end
+
+if total_values == 4
+	puts "We found all the values"
+else
+	puts "We didn't find all the values!!!"
+end
+
+FileUtils.rm_r rootdb
+
+# Caches should still have a single entry since we only searched through them only once.
+#index_name.data.size.should  eq 1
+#index_color.data.size.should eq 1

src/dodb/storage.cr

@@ -350,8 +350,7 @@ abstract class DODB::Storage(V)
 		end
 	end
 
-	private def clear_storage_cache!
-		puts "DODB::Storage(V) clear_storage_cache! (no cache)"
+	def clear_storage_cache!
 		# There's no cache by default.
 		# This function has to be changed in storage implementations.
 	end
@@ -369,7 +368,6 @@ abstract class DODB::Storage(V)
 	# WARNING: slow operation.
 	# NOTE: clears all caches (`storage` and `triggers`).
 	def reindex_everything!
-		clear_cache!
 		nuke_triggers!
 
 		each_with_key() do |item, key|

src/dodb/storage/cached.cr

@@ -45,15 +45,30 @@ class DODB::Storage::Cached(V) < DODB::Storage(V)
 
 		@cached_last_key = init_last_key
 
+		# Load the database (to fill up the cache) at start-up.
+		load_db!
+	end
+
+	# `Storage::Cached` doesn't perform look-ups from the filesystem by itself upon requests,
+	# the entire database has to be initialized by reading the entire on-disk data in order to
+	# fill up the cache.
+	#
+	# This function is called once at start-up and should be used whenever the entire cache
+	# is cleaned up for whatever reason, otherwise the database will be seen as empty.
+	#
+	# WARNING: beware of triggers.
+	# NOTE: this function has no use in `Storage::Common` because the database entries are read from the disk
+	#	when the value isn't in cache.
+	#       This function doesn't exist in `Storage::Uncached` since there is no cache.
+	def load_db!
 		# Load the database in RAM at start-up.
 		DODB::Storage::Uncached(V).new(@directory_name).each_with_key do |v, key|
-			puts "\rloading data from #{@directory_name} at key #{key}"
+			# puts "\rloading data from #{@directory_name} at key #{key}"
 			self[key] = v
 		end
 	end
 
-	private def clear_storage_cache!
-		puts "DODB::Storage::Cached(V) clear_storage_cache!"
+	def clear_storage_cache!
 		data.clear
 	end
 

src/dodb/storage/common.cr

@@ -46,12 +46,17 @@ class DODB::Storage::Common(V) < DODB::Storage::Cached(V)
 		@cached_last_key = init_last_key
 	end
 
-	private def clear_storage_cache!
-		puts "DODB::Storage::Common(V) clear_storage_cache!"
+	def clear_storage_cache!
 		data.clear
 		@lru = EfficientLRU(Int32).new lru.max_entries
 	end
 
+	# :nodoc:
+	# There is no need for this function in `Storage::Common`,
+	# therefore it is put in private and removed from the documentation.
+	private def load_db!
+	end
+
 	# Verifies that the value is in cache, or read it on disk.
 	# Pushes the key in the lru.
 	def [](key : Int32) : V

src/dodb/trigger.cr

@@ -31,7 +31,6 @@ abstract class DODB::Trigger(V)
 
 	# Removes all cached values.
 	def clear_cache!
-		puts "DODB::Trigger(V) no cache"
 		# By default, there is no cache.
 	end
 

src/dodb/trigger/index.cr

@@ -345,7 +345,6 @@ class DODB::Trigger::IndexCached(V) < DODB::Trigger::Index(V)
 	end
 
 	def clear_cache!
-		puts "DODB::Trigger::IndexCached(V) clear_cache!"
 		data.clear
 	end
 

src/dodb/trigger/partition.cr

@@ -261,7 +261,6 @@ class DODB::Trigger::PartitionCached(V) < DODB::Trigger::Partition(V)
 	end
 
 	def clear_cache!
-		puts "DODB::Trigger::PartitionCached(V) clear_cache!"
 		data.clear
 	end
 

src/dodb/trigger/tags.cr

@@ -301,7 +301,6 @@ class DODB::Trigger::TagsCached(V) < DODB::Trigger::Tags(V)
 	end
 
 	def clear_cache!
-		puts "DODB::Trigger::TagsCached(V) clear_cache!"
 		data.clear
 	end