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Secciones/state_of_the_art.tex
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\chapter{Related work}
\label{cha:state-art}
Slicing was proposed \cite{Wei81} and improved until the proposal of the current system (the SDG) \carlos{(citation)}. Specifically in the context of exceptions, multiple approaches have been attempted, with varying degrees of success. There exist commercial solutions for various programming languages: \carlos{name them and link}.
In the realm of academia, there exists no definite solution. One of the most relevant initial proposal\added{s} \cite{AllH03}, although not the first one \cite{SinH98,SinHR99} to target Java specifically.
\deleted{S}\added{Program s}licing was proposed \cite{Wei81} and \added{iteratively }improved\sergio{un par de citas de papers intermedios que haya} until the proposal of the current\added{ly} \deleted{system}\added{most used program representation structure,} \deleted{(}the SDG\deleted{)} \carlos{(citation)}. Specifically\added{,} in the context of exceptions, multiple approaches have been attempted\deleted{,} with varying\sergio{diverse?} degrees of success. There exist commercial solutions for various programming languages: \carlos{name them and link}.
In the realm of academia, there exists no definite solution. One of the most relevant initial proposal\added{s} \added{was Allen and Horwitz (}\cite{AllH03}\added{)}, although \added{it was} not the first one \deleted{\cite{SinH98,SinHR99}} \deleted{to} target\added{ing} Java \added{programming language} specifically\added{(\cite{SinH98,SinHR99})}.
It uses the existing proposals for \textit{return}, \textit{goto} and other unconditional jumps to model the behavior of \textit{throw} statements. Control flow inside \textit{try-catch-finally} statements is simulated, both for explicit \textit{throw} and those nested inside a method call. The base algorithm is presented, and then the proposal is detailed as changes. Unchecked exceptions are considered but regarded as ``worthless'' to include, due to the increase in size of the slices, which reduces their effectiveness as a debugging tool. This is due to the number of unchecked exceptions embedded in normal Java instructions, such as \texttt{NullException} in any instance field or method, \texttt{IndexOutOfBoundsException} in array accesses and countless others. On top of that, handling \textit{unchecked} exceptions opens the problem of calling an API to which there is no analyzable source code, either because the module was compiled before-hand or because it is part of a distributed system. The first should not be an obstacle, as class files can be easily decompiled. The only information that may be lost is variable names and comments, which \added{do not}\deleted{don't} affect a slice's precision, only its readability.
\deleted{It}\added{In \cite{AllH03}, Allen and Horwitz benefit from the}\deleted{uses} the existing proposals for \textit{return}, \textit{goto} and other unconditional jumps\sergio{anyadir citas} to model the behavior of \textit{throw} statements. Control flow inside \textit{try-catch-finally} statements \deleted{is}\added{was} simulated, both for explicit \textit{throw} and \added{all possible \textit{throws}} nested inside a method call. The base algorithm is presented, and then the proposal is detailed as changes. Unchecked exceptions are considered but regarded as ``worthless'' to include, due to the increase in size of the slices, which reduces their effectiveness as a debugging tool. This is due to the number of unchecked exceptions embedded in normal Java instructions, such as \texttt{NullException} in any instance field or method, \texttt{IndexOutOfBoundsException} in array accesses and countless others. On top of that, handling \textit{unchecked} exceptions opens the problem of calling an API to which there is no analyzable source code, either because the module was compiled before-hand or because it is part of a distributed system. The first should not be an obstacle, as class files can be easily decompiled. The only information that may be lost is variable names and comments, which \added{do not}\deleted{don't} affect a slice's precision, only its readability.
Chang and Jo \cite{JoC04} present an alternative to the CFG by computing exception-induced control flow separately from the traditional control flow computation, but go no further into the ramifications it entails for the PDG and the SDG.