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wip singleton analysis

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Claudio Maggioni 2022-10-17 14:10:39 +02:00
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@ -24,24 +24,37 @@ already know as library clients.
\subsection {Projects Considered}
We considered the following GitHub repositories:
\begin{description}
\item[vavr-io/vavr] a Java library for functional programming, discarded as
the project is less than 20K LOC and doesn't meet the selection criteria;
\item[bitcoin4j/bitcoin4j] a Java implementation of the bitcoin protocol,
discarded as the project is distributed in several subprojects;
\item[FasterXML/jackson-core] a popular Java JSON serialization and
deserialization library. This repository contains the \textit{core}
component of the library, i.e. the library abstractions and interface to
support additional modules and the main JSON serialization and
deserialization capabilities. We chose this library because it meets the
\item[FasterXML/jackson-core] a Java JSON serialization and
deserialization library. We chose this library because it meets the
selection criteria, it doesn't rely on external components for its
execution, and its project structure uses a single Maven module for its
sources and thus easy to analyze.
\end{description}
Therefore we chose \textbf{FasterXML/jackson-core}, specifically the sources
under the git tag \texttt{jackson-core-2.13.4}, the latest stable version of the
library at this time.
\subsection {The Jackson Core Library}
As already mentioned, \texttt{Jackson} is a library that offers serialization
and deseralization capabilities in JSON format. The library is highly extensible
and customizable through a robust but flexible API and module suite that allows
to change the serialization and deserialization rules, or in the case of the
\texttt{jackson-dataformat-xml} module, to allow to target XML instead of JSON.
The chosen repository contains only the \textit{core} module of Jackson. The
\textit{core} module implements the necessary library abstractions and
interfaces to allow other modules to be plugged-in. Additionally, the
\textit{core} module implements the tokenizer and low-level abstractions to work
with the JSON format.
We chose to analyze version 2.13.4 of the module (corresponding to the code
under the git tag \texttt{jackson-core-2.13.4}) because it is the latest stable
version available at the time of writing.
\section{Analysis}
@ -57,6 +70,8 @@ instead, as it is the previous LTS version.
An XML dump of the \textit{Pattern4j} analysis results are included in the
submission as the file \texttt{analysis.xml}.
\subsection{Comments}
\begin{itemize}
\item Lots of false positives for the Singleton pattern. Example,
@ -64,6 +79,20 @@ submission as the file \texttt{analysis.xml}.
public static final instance of it, but reading the documentation the class
represents (short) JSON string literals and therefore is clearly
initialized by client code.
\begin{description}
\item[sym.Name1, JsonLocation, DefaultIndenter,
util.DefaultPrettyPrinter\$FixedSpaceIndenter] not a singleton (detected
cause of "convenient" default instance given as static final field), the
constructor is not used but the class is extensible
\item[JsonPointer, filter.TokenFilter] like above, but constructors are protected
\item[JsonpCharacterEscapes, util.DefaultPrettyPrinter\$NopIndenter,
Version] a singleton but with a public constructor that is never called
in the module code, may be called in tests
\item[io.JsonStringEncoder] like above, but the class is final
\item[util.InternCache, io.CharTypes\$AltEscapes]
actual singleton, thread-unsafe initialization
\item[io.ContentReference] like above, but constructor is protected
\end{description}
\item TBD
\end{itemize}
\end{document}