strategy and state pattern done

report.tex

@@ -206,8 +206,6 @@ None found
 \subsection{Observer Pattern}
 None found
 
-\subsection{Strategy Pattern}
-None found
 
 \subsection{State Pattern}
 Among the design patterns \textit{Pattern4J} detects, the state pattern is
@@ -217,22 +215,39 @@ state of a finite state machine the context class implements. In other words,
 the state pattern chooses the concrete strategy to use through the state of the
 context.
 
+By analyzing the \textit{Pattern4J} results and the code, we can say that all
+the instances of the state pattern the tool finds are false positives. Namely:
+
 \begin{description}
-  \item[util.DefaultPrettyPrinter] false positive, strategy pattern;
-  \item[JsonFactory] false positive, \textit{InputDecorator \_inputDecorator},
-\textit{OutputDecorator \_outputDecorator}, \textit{SerializedString
-\_rootValueSeparator} are strategy instances (more
-specifically a way to pre-process input before Jackson parses it, labeled as
-``decorator'' by Jackson developers but not really a decorator pattern
-application since InputDecorator is not a subclass of any component to
-decorate); 
-  \item[json.WriterBasedJsonGenerator] false positive,
-    \textit{SerializableString \_currentEscape} is a simple \textit{String}-like
-    object that gets updated based on the parsing state.
-  \item[util.DefaultPrettyPrinter] ??? WIP
+  \item[util.DefaultPrettyPrinter \textit{\_inputDecorator} and
+    \textit{\_outputDecorator}]  are fields flagged as states, thus flagging the
+    class as a state pattern instance. However, no ``state'' akin to a
+    finite-state machine is maintained by the class to determine which
+    implementation of these fields to invoke. What is detected are more likely
+    lightweight implementations of the strategy pattern, since these fields can
+    be mutated through matching getters and setters. Additionally, the
+    documentation of each of the matching \textit{...Decorator} field types
+    (namely interfaces) states that implementors are meant to be algorithms to
+    pre-process input before the formatting process (a feature labeled as
+  ``decorator'' w.r.t.\ the library, not to be confused with the decorator
+pattern); 
+  \item[util.DefaultPrettyPrinter \_objectIndenter and \_arrayIndenter] are
+    false positives too, and are likely strategy patterns too for the reasons
+    described above.
+  \item[util.DefaultPrettyPrinter \_rootValueSeparator] is flagged as a state
+    field too, however the field is simply a boxed \textit{String-like}
+    immutable data structure (i.e.\ \textit{SerializableString}) that is
+    swapped during the pretty-printer parsing logic;
+  \item[json.WriterBasedJsonGenerator \_currentEscape] is a false positive for
+    the same reasons described above.
 \end{description}
 
-WIP instances and examples
+\subsection{Strategy Pattern}
+\textit{Pattern4j} detects no instance of the strategy pattern in Jackson,
+however the previous section regarding the state pattern referenced some false
+positives that were indeed applications of this pattern. Due to the flexibility
+of Jackson, there are many more instances of the strategy pattern to configure
+and customize the serialization and deserialization pipeline in several stages.
 
 \subsection{Template Method Pattern}
 Due to the extendibility of Jackson, it is of no surprise that the template