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class EXAMPLE5
-- Compilation:
-- compile_to_jvm example5
-- del example5.class (Windows), rm example5.class (Unix)
-- javac CSimple.java
-- Execution:
-- java CSimple
-- This example demonstrates how to create and call a compiled Eiffel system
-- from Java, how to throw Java exceptions from Eiffel, and how Eiffel
-- contract assertion violations throw Java exceptions.
creation make
feature
make is
do
-- set attribute eiffel_integer
eiffel_integer := 1
-- fake a call to proc1 and proc2 so they won't be optimized out at compile time
if False then
proc1( 0 )
proc2( 0 )
end
end
feature
eiffel_integer: INTEGER
feature
proc1( i: INTEGER ) is
-- throws a Java exception depending on argument value
local
e: POINTER
javaString: POINTER
javaStringBytes: POINTER
string_length: INTEGER
s: STRING
flag: BOOLEAN
do
if i >= 0 then
eiffel_integer := i
else
create s.make( 48 )
s.append( "Exception in example5.proc1: i=" )
s.append( i.out )
s.append( " < 0" )
javaString := new_java_lang_String( checkcast_aB( s.to_external ), 0, s.count )
e := new_java_lang_Exception( checkcast_java_lang_String( javaString ) )
throw_exception( checkcast_java_lang_Exception( e ) )
end
end
proc2( i: INTEGER ) is
-- precondition assertion violation throws Java exception
require
i_ok: i >= 0
do
eiffel_integer := i
end
feature -- externals
new_java_lang_String( a1: POINTER; a2: INTEGER; a3: INTEGER ): POINTER is
external "Java class java.lang.String new (byte[],int,int)"
end
checkcast_java_lang_String( p: POINTER ): POINTER is
external "Java class java.lang.String checkcast"
end
checkcast_aB( p: POINTER ): POINTER is
external "Java class byte[] checkcast"
end
new_java_lang_Exception( a1: POINTER ): POINTER is
external "Java class java.lang.Exception new (java.lang.String)"
end
checkcast_java_lang_Exception( p: POINTER ): POINTER is
external "Java class java.lang.Exception checkcast"
end
throw_exception( p: POINTER ) is
external "Java exception java.lang.Exception throw"
end
end -- EXAMPLE5
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