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https://issues.apache.org/jira/browse/THRIFT-4476?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16340683#comment-16340683
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Ozan Can Altiok commented on THRIFT-4476:
-----------------------------------------
I think it is related to the compiler rather than the library since the error
gets thrown during thrift compilation. So I added `Java - Compiler`.
> Typecasting problem on list items
> ---------------------------------
>
> Key: THRIFT-4476
> URL: https://issues.apache.org/jira/browse/THRIFT-4476
> Project: Thrift
> Issue Type: Bug
> Components: Java - Compiler
> Affects Versions: 0.11.0
> Reporter: Ozan Can Altiok
> Priority: Major
>
> I was trying to add the following into a thrift interface file.
> {{const list<double> timeCoefficients = [24, 60, 60, 1000, 1000, 1000]}}
> With the definition given above the {{.thrift}} file compiled properly.
> However, I noticed that in Python, the items in {{timeCoefficients}} are
> considered to be integer although the list has been defined to include items
> of {{double}} type. Then I modified the definition as given below to make
> sure all the items are of type {{double}}.
> {{const list<double> timeCoefficients = [24.0, 60.0, 60.0, 1000.0, 1000.0,
> 1000.0]}}
> After the change, I ran into the following error during compilation.
> {{[ERROR] .../TimeCoefficients.java:[402,48] error: no suitable method found
> for add(int)}}
> {{[ERROR] method Collection.add(Double) is not applicable}}
> {{[ERROR] (argument mismatch; int cannot be converted to Double)}}
> {{[ERROR] method List.add(Double) is not applicable}}
> {{[ERROR] (argument mismatch; int cannot be converted to Double)}}
> Next, I changed the line as follows and the compilation became successful.
> {{const list<double> timeCoefficients = [24.1, 60.1, 60.1, 1000.1, 1000.1,
> 1000.1]}}
> When I reviewed the generated Java source files, I discovered that
> {{const list<double> timeCoefficients = [24, 60, 60, 1000, 1000, 1000]}}
> compiles to
> {{public static final java.util.List<java.lang.Double> timeCoefficients = new
> java.util.ArrayList<java.lang.Double>();}}
> {{static {}}
> {{ timeCoefficients.add((double)24);}}
> {{ timeCoefficients.add((double)60);}}
> {{ timeCoefficients.add((double)60);}}
> {{ timeCoefficients.add((double)1000);}}
> {{ timeCoefficients.add((double)1000);}}
> {{ timeCoefficients.add((double)1000);}}
> {{}}}
> whilst
> {{const list<double> timeCoefficients = [24.0, 60.0, 60.0, 1000.0, 1000.0,
> 1000.0]}}
> compiles to
> {{public static final java.util.List<java.lang.Double> timeCoefficients = new
> java.util.ArrayList<java.lang.Double>();}}
> {{static {}}
> {{ timeCoefficients.add(24);}}
> {{ timeCoefficients.add(60);}}
> {{ timeCoefficients.add(60);}}
> {{ timeCoefficients.add(1000);}}
> {{ timeCoefficients.add(1000);}}
> {{ timeCoefficients.add(1000);}}
> {{}}}
> which leads to an error.
> When I modified this line as follows
> {{const list<double> timeCoefficients = [24.1, 60.1, 60.1, 1000.1, 1000.1,
> 1000.1]}}
> this line compiled to
> {{public static final java.util.List<java.lang.Double> timeCoefficients = new
> java.util.ArrayList<java.lang.Double>();}}
> {{static {}}
> {{ timeCoefficients.add(24.1);}}
> {{ timeCoefficients.add(60.1);}}
> {{ timeCoefficients.add(60.1);}}
> {{ timeCoefficients.add(1000.1);}}
> {{ timeCoefficients.add(1000.1);}}
> {{ timeCoefficients.add(1000.1);}}
> {{}}}
> My guess is that, even if I put {{.0}} at the end of each numeric constant,
> on the Java side, Thrift compiler considers them to be {{double}} and does no
> typecasts. However, the {{.0}} s are getting lost somewhere and the items
> become integers in the generated Java code. Thus, when it comes to populating
> the array, Java cannot succeed. {{Double}} s cannot be unboxed to integer and
> Java thinks {{int}} and {{Double}} are not related.
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