topics: add software concepts topic

It is an overview of some of the concepts
one should have heard as a software developer.
The topics are not discussed in depth.
For the patterns part the explanations on
https://github.com/iluwatar/java-design-patterns are used.

Before the breaks we go through the code examples look for
the learned patterns and concepts.

Issue: #65

topics/CMakeLists.txt

@@ -5,6 +5,7 @@ add_subdirectory(build_systems)
 add_subdirectory(docker)
 add_subdirectory(git)
 add_subdirectory(linux)
+add_subdirectory(sw_concepts)
 add_subdirectory(testing)
 add_subdirectory(tools_and_varia)
 

topics/sw_concepts/CMakeLists.txt

@@ -0,0 +1,7 @@
+include(js_document)
+
+js_slides(sw_concept_slides sw_concept_slides.md)
+js_slides(sw_concept_code_examples sw_concept_code_examples.md)
+
+file(GLOB_RECURSE code RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} "code/*")
+js_add_to_global_archive_file_list(${code})

topics/sw_concepts/code/abstractions.py

@@ -0,0 +1,120 @@
+#!/usr/bin/env python
+import errno
+import math
+import os
+import sys
+import time
+from optparse import OptionParser
+
+# Censored hardware prototype2 and series (tsl2550) value range: 0 - 4015, daylight: 544
+# Censored hardware v3 (opt3001) value range: 0 - 36157, daylight: 290
+INPUT_MIN = 0
+INPUT_MAX_TSL2550 = 544
+INPUT_MAX_OPT3001 = 290
+INPUT_THRESHOLD = 11
+
+# Censored hardware prototype2 (Intel backlight) value range: 0 - 937
+# Censored hardware series Device (Intel backlight) value range: 0 - 7500
+OUTPUT_MIN_FACTOR = 0.2
+OUTPUT_CHANGE_MAX_FACTOR = 0.005
+
+sensor_value_lux_approx_map = [
+    0, 1, 2, 3, 4, 5, 6, 7,
+    8, 9, 10, 11, 12, 13, 14, 15,
+    16, 18, 20, 22, 24, 26, 28, 30,
+    32, 34, 36, 38, 40, 42, 44, 46,
+    49, 53, 57, 61, 65, 69, 73, 77,
+    81, 85, 89, 93, 97, 101, 105, 109,
+    115, 123, 131, 139, 147, 155, 163, 171,
+    179, 187, 195, 203, 211, 219, 227, 235,
+    247, 263, 279, 295, 311, 327, 343, 359,
+    375, 391, 407, 423, 439, 455, 471, 487,
+    511, 543, 575, 607, 639, 671, 703, 735,
+    767, 799, 831, 863, 895, 927, 959, 991,
+    1039, 1103, 1167, 1231, 1295, 1359, 1423, 1487,
+    1551, 1615, 1679, 1743, 1807, 1871, 1935, 1999,
+    2095, 2223, 2351, 2479, 2607, 2735, 2863, 2991,
+    3119, 3247, 3375, 3503, 3631, 3759, 3887, 4015
+]
+
+
+def main():
+    input_max = INPUT_MAX_TSL2550
+    output_last_value = None
+
+    parser = OptionParser()
+    _, args = parser.parse_args()
+
+    if len(args) != 3:
+        raise Exception("wrong number of arguments")
+
+    path = args[0]
+    input_path = args[1]
+    output_path = args[2]
+    opt3001 = "in_illuminance_input" in os.readlink(input_path)
+
+    input_last_value = INPUT_MIN - INPUT_THRESHOLD
+    with open(path) as f:
+        output_max = int(f.readline().strip())
+    output_min = int(math.ceil(output_max * OUTPUT_MIN_FACTOR))
+    output_change_max = int(math.ceil(output_max * OUTPUT_CHANGE_MAX_FACTOR))
+
+    while True:
+        try:
+            if opt3001:
+                try:
+                    with open(input_path) as f1:
+                        input_value = float(f1.readline().strip())
+                except IOError:
+                    # This driver generates a read error if very little light is present
+                    input_value = INPUT_MIN
+            else:
+                with open(input_path) as f:
+                    input_value = int(f.readline().strip())
+                if 0 <= input_value < len(sensor_value_lux_approx_map):
+                    input_value = sensor_value_lux_approx_map[input_value]
+                else:
+                    input_value = input_last_value
+
+            input_value = min(input_value, input_max)
+
+            # Ignore small input value changes
+            if abs(input_value - input_last_value) < INPUT_THRESHOLD:
+                input_value = input_last_value
+
+            a = (input_value - INPUT_MIN) / float(input_max - INPUT_MIN)
+            value1 = int(a * float(output_max - output_min) + output_min)
+            output_value = min(value1, output_max)
+
+            if output_last_value is None:
+                output_value = output_value
+            elif output_value >= output_last_value:
+                output_value = min(output_value, output_last_value + output_change_max)
+            else:
+                output_value = max(output_value, output_last_value - output_change_max)
+            dimmed_value = output_value
+
+            if output_value != output_last_value:
+                print(f"input: %4i (%4.1f%%), output: %4i (%4.1f%%), dimmed: %4i (%4.1f%%)",
+                      input_value, 100 * (input_value - INPUT_MIN) / float(input_max - INPUT_MIN),
+                      output_value, 100 * (output_value - output_min) / float(output_max - output_min),
+                      dimmed_value, 100 * (dimmed_value - output_min) / float(output_max - output_min))
+                sys.stdout.flush()
+
+            with open(output_path, "w") as f:
+                output_last_value = output_value
+                f.write(str(output_value))
+
+            input_last_value = input_value
+        except IOError as e:
+            # Ignore EGAIN errors which may happen if the I2C bus is busy
+            if e.errno != errno.EAGAIN:
+                raise e
+
+        time.sleep(0.01)
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

topics/sw_concepts/images/dependency-inversion/no-dependency-inversion.puml

@@ -0,0 +1,13 @@
+@startuml
+
+package domain {
+    class TransactionObserver
+}
+
+package persistence {
+    class DBTransactionRepository
+}
+
+TransactionObserver --> DBTransactionRepository
+
+@enduml

topics/sw_concepts/images/dependency-inversion/with-dependency-inversion.puml

@@ -0,0 +1,15 @@
+@startuml
+
+package domain {
+    class TransactionObserver
+
+    interface TransactionRepository
+}
+
+package persistence {
+    class DBTransactionRepository implements domain.TransactionRepository
+}
+
+TransactionObserver --> TransactionRepository
+
+@enduml

topics/sw_concepts/images/interface-segregation/java-interface-segregation.puml

@@ -0,0 +1,56 @@
+@startuml
+
+!theme plain
+skinparam linetype ortho
+
+class ArrayList<E> {
+}
+interface Cloneable << interface >>
+interface Collection<E> << interface >> {
+  + remove(Object): boolean
+  + clear(): void
+  + removeIf(Predicate<E>): boolean
+  + isEmpty(): boolean
+  + addAll(Collection<E>): boolean
+  + size(): int
+  + hashCode(): int
+  + contains(Object): boolean
+  + add(E): boolean
+}
+class LinkedHashSet<E> {
+}
+interface List<E> << interface >> {
+  + sort(Comparator<E>): void
+  + isEmpty(): boolean
+  + contains(Object): boolean
+  + add(E): boolean
+  + set(int, E): E
+  + remove(Object): boolean
+  + lastIndexOf(Object): int
+  + size(): int
+  + remove(int): E
+  + get(int): E
+  + add(int, E): void
+  + clear(): void
+  + indexOf(Object): int
+  + containsAll(Collection<?>): boolean
+}
+interface Serializable << interface >>
+interface Set<E> << interface >> {
+  + contains(Object): boolean
+  + add(E): boolean
+  + remove(Object): boolean
+  + isEmpty(): boolean
+  + clear(): void
+  + size(): int
+}
+
+ArrayList      -[#008200,dashed]--^  Cloneable
+ArrayList      -[#008200,dashed]--^  List
+ArrayList      -[#008200,dashed]--^  Serializable
+LinkedHashSet  -[#008200,dashed]--^  Cloneable
+LinkedHashSet  -[#008200,dashed]--^  Serializable
+LinkedHashSet  -[#008200,dashed]--^  Set
+List           -[#008200,plain]--^  Collection
+Set            -[#008200,plain]--^  Collection
+@enduml