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Diffstat (limited to 'gcc/java/gcj.texi')
| -rw-r--r-- | gcc/java/gcj.texi | 63 |
1 files changed, 60 insertions, 3 deletions
diff --git a/gcc/java/gcj.texi b/gcc/java/gcj.texi index 21cc2a5770e..84e0e167288 100644 --- a/gcc/java/gcj.texi +++ b/gcc/java/gcj.texi @@ -2,6 +2,13 @@ @setfilename gcj.info @settitle Guide to GNU gcj +@c Merge the standard indexes into a single one. +@syncodeindex fn cp +@syncodeindex vr cp +@syncodeindex ky cp +@syncodeindex pg cp +@syncodeindex tp cp + @include gcc-common.texi @c Note: When reading this manual you'll find lots of strange @@ -124,6 +131,7 @@ files and object files, and it can read both Java source code and * About CNI:: Description of the Compiled Native Interface * System properties:: Modifying runtime behavior of the libgcj library * Resources:: Where to look for more information +* Index:: Index. @end menu @@ -1426,7 +1434,8 @@ alternative to the standard JNI (Java Native Interface). @menu * Basic concepts:: Introduction to using CNI@. * Packages:: How packages are mapped to C++. -* Primitive types:: Handling Java types in C++. +* Primitive types:: Handling primitive Java types in C++. +* Reference types:: Handling Java reference types in C++. * Interfaces:: How Java interfaces map to C++. * Objects and Classes:: C++ and Java classes. * Class Initialization:: How objects are initialized. @@ -1623,7 +1632,7 @@ to avoid disappointment. @subsection Reference types associated with primitive types In Java each primitive type has an associated reference type, -e.g.: @code{boolean} has an associated @code{java.lang.Boolean} class. +e.g.: @code{boolean} has an associated @code{java.lang.Boolean.TYPE} class. In order to make working with such classes easier GCJ provides the macro @code{JvPrimClass}: @@ -1637,6 +1646,41 @@ JvPrimClass(void) @result{} java.lang.Void.TYPE @end deffn +@node Reference types +@section Reference types + +A Java reference type is treated as a class in C++. Classes and +interfaces are handled this way. A Java reference is translated to a +C++ pointer, so for instance a Java @code{java.lang.String} becomes, +in C++, @code{java::lang::String *}. + +CNI provides a few built-in typedefs for the most common classes: +@multitable @columnfractions .30 .25 .60 +@item @strong{Java type} @tab @strong{C++ typename} @tab @strong{Description} +@item @code{java.lang.Object} @tab @code{jobject} @tab Object type +@item @code{java.lang.String} @tab @code{jstring} @tab String type +@item @code{java.lang.Class} @tab @code{jclass} @tab Class type +@end multitable +@cindex jobject +@cindex jstring +@cindex jclass + +Every Java class or interface has a corresponding @code{Class} +instance. These can be accessed in CNI via the static @code{class$} +field of a class. The @code{class$} field is of type @code{Class} +(and not @code{Class *}), so you will typically take the address of +it. +@cindex class$ + +Here is how you can refer to the class of @code{String}, which in +Java would be written @code{String.class}: + +@example +using namespace java::lang; +doSomething (&String::class$); +@end example + + @node Interfaces @section Interfaces @@ -1896,10 +1940,17 @@ The name of this function may change in the future. @deftypefun jobjectArray JvNewObjectArray (jsize @var{length}, jclass @var{klass}, jobject @var{init}) -Here @code{klass} is the type of elements of the array and +This creates a new array whose elements have reference type. +@code{klass} is the type of elements of the array and @code{init} is the initial value put into every slot in the array. @end deftypefun +@example +using namespace java::lang; +JArray<String *> *array + = (JArray<String *> *) JvNewObjectArray(length, &String::class$, NULL); +@end example + @subsection Creating arrays @@ -2761,4 +2812,10 @@ a free software Java class library test suite which is being written because the JCK is not free. See @uref{http://sources.redhat.com/mauve/} for more information. + +@node Index +@unnumbered Index + +@printindex cp + @bye |