contrib/jwrapper: reorganize and document the different names of a JavaType
[nit.git] / contrib / jwrapper / src / code_generator.nit
index 45ce666..dfa5cab 100644 (file)
@@ -1,6 +1,7 @@
 # This file is part of NIT (http://www.nitlanguage.org).
 #
 # Copyright 2014 Frédéric Vachon <fredvac@gmail.com>
+# Copyright 2015 Alexis Laferrière <alexis.laf@xymus.net>
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # Services to generate extern class `in "Java"`
 module code_generator
 
-intrude import types
+intrude import model
 
 class CodeGenerator
 
-       var with_attributes: Bool
+       # Path to the output file
+       var file_name: String
+
+       # Model of Java class being wrapped
+       var model: JavaModel
+
+       # Comment out methods with unknown (unwrapped) types
        var comment_unknown_types: Bool
-       var file_out: OFStream
-       var java_class: JavaClass
-       var nb_params: Int
-       var module_name: String
-       fun code_warehouse: CodeWarehouse do return once new CodeWarehouse
 
-       init (file_name: String, jclass: JavaClass, with_attributes, comment: Bool)
-       do
-               file_out = new OFStream.open(file_name)
-               module_name = file_name.substring(0, file_name.search(".nit").from)
-               self.java_class = jclass
-               self.with_attributes = with_attributes
-               self.comment_unknown_types = comment
+       # Generate stub classes for unknown types used in the generated module
+       var stub_for_unknown_types: Bool
+
+       # Output file
+       var file_out: Writer = new FileWriter.open(file_name) is lazy, writable
+
+       # Name of the Nit module to generate
+       var module_name: nullable String is lazy do
+               if file_name.file_extension == "nit" then
+                       # Output file ends with .nit, we expect it to be a valid name
+                       return file_name.basename(".nit")
+               else return null
        end
 
+       # Generate the Nit module into `file_out`
        fun generate
        do
-               var jclass = self.java_class
+               # License
+               file_out.write license
+
+               # Module declaration
+               var module_name = module_name
+               if module_name != null then file_out.write "module {module_name}\n"
+               file_out.write "\n"
+
+               # All importations
+               var imports = new HashSet[String]
+               imports.add "import java\n"
+               for key, jclass in model.classes do
+                       for import_ in jclass.imports do imports.add "import android::{import_}\n"
+               end
+               file_out.write imports.join("\n")
+               file_out.write "\n"
 
-               var class_content = new Array[String]
-               class_content.add(gen_class_header(jclass.class_type))
+               for key, jclass in model.classes do
 
-               if with_attributes then
-                       for id, jtype in jclass.attributes do class_content.add(gen_attribute(id, jtype))
-               end
+                       generate_class_header(jclass.class_type)
 
-               for id, methods_info in jclass.methods do
-                       for method_info in methods_info do
-                               var nid = id
-                               if methods_info.length > 1 then nid += "{methods_info.index_of(method_info)}"
-                               class_content.add gen_method(id, nid, method_info.return_type, method_info.params)
+                       for id, signatures in jclass.methods do
+                               for signature in signatures do if not signature.is_static then
+                                       generate_method(jclass, id, id, signature.return_type, signature.params)
+                                       file_out.write "\n"
+                               end
                        end
-               end
-               class_content.add("\nend\n")
 
-               var wrappers = new Array[String]
-               for jtype in jclass.unknown_types do
-                       if jtype == jclass.class_type then continue
-                       wrappers.add("\n")
-                       wrappers.add(gen_unknown_class_header(jtype))
-               end
+                       # Constructors
+                       for constructor in jclass.constructors do
+                               var complex = jclass.constructors.length != 1 and constructor.params.not_empty
+                               var base_name = if complex then "from" else ""
+                               var name = jclass.nit_name_for(base_name, constructor.params, complex)
+
+                               generate_constructor(jclass, constructor, name)
+                       end
 
-               var imports = new Array[String]
-               imports.add("import mnit_android\n")
-               for import_ in jclass.imports do
-                       imports.add("import android::{import_}\n")
+                       # Attributes
+                       for id, attribute in jclass.attributes do if not attribute.is_static then
+                               generate_getter_setter(jclass, id, attribute)
+                       end
+
+                       # JNI services
+                       generate_jni_services jclass.class_type
+
+                       # Close the class
+                       file_out.write "end\n\n"
+
+                       # Static functions as top-level methods
+                       var static_functions_prefix = jclass.class_type.extern_name.to_snake_case
+                       for id, signatures in jclass.methods do
+                               for signature in signatures do if signature.is_static then
+                                       var nit_id = static_functions_prefix + "_" + id
+                                       generate_method(jclass, id, nit_id, signature.return_type, signature.params, is_static=true)
+                                       file_out.write "\n"
+                               end
+                       end
+
+                       # Static attributes as top-level getters and setters
+                       for id, attribute in jclass.attributes do if attribute.is_static then
+                               generate_getter_setter(jclass, id, attribute)
+                       end
+
+                       # Primitive arrays
+                       for d in [1..opt_arrays.value] do
+                               generate_primitive_array(jclass, d)
+                       end
                end
 
-               file_out.write(gen_licence)
-               file_out.write("module {module_name}\n")
-               file_out.write(imports.join(""))
-               file_out.write("\n")
-               file_out.write(class_content.join(""))
-               file_out.write(wrappers.join(""))
+               if stub_for_unknown_types then
+                       for jtype, nit_type in model.unknown_types do
+                               generate_unknown_class_header(jtype)
+                               file_out.write "\n"
+                       end
+               end
        end
 
-       fun gen_licence: String
-       do
-               return """# This file is part of NIT (http://www.nitlanguage.org).
-#
-# Copyright [Year] [Author name] <Author e-mail>
+       # License for the header of the generated Nit module
+       var license = """
+# This file is part of NIT (http://www.nitlanguage.org).
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -97,353 +141,283 @@ class CodeGenerator
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# This code has been generated using `javap`
-"""
-       end
+# This code has been generated using `jwrapper`
+""" is writable
 
-       fun gen_class_header(jtype: JavaType): String
+       private fun generate_class_header(jtype: JavaType)
        do
-               var temp = new Array[String]
-               temp.add("extern class Native{jtype.id} in \"Java\" `\{ {jtype} `\}\n")
-               temp.add("\tsuper JavaObject\n\tredef type SELF: Native{jtype.id}\n\n")
-
-               return temp.join("")
+               var nit_type = model.java_to_nit_type(jtype)
+               file_out.write "# Java class: {jtype}\n"
+               file_out.write "extern class {nit_type} in \"Java\" `\{ {jtype.extern_equivalent} `\}\n"
+               file_out.write "\tsuper JavaObject\n\n"
        end
 
-       fun gen_unknown_class_header(jtype: JavaType): String
+       private fun generate_unknown_class_header(jtype: JavaType)
        do
-               var nit_type: NitType
-               if jtype.extern_name.has_generic_params then
-                       nit_type = jtype.extern_name.generic_params.first
-               else
-                       nit_type = jtype.extern_name
-               end
-
-               var temp = new Array[String]
-               temp.add("extern class {nit_type} in \"Java\" `\{ {jtype.to_package_name} `\}\n")
-               temp.add("\tsuper JavaObject\n\tredef type SELF: {nit_type}\n\nend\n")
+               var nit_type = jtype.extern_name
 
-               return temp.join("")
+               file_out.write "extern class {nit_type} in \"Java\" `\{ {jtype.extern_equivalent} `\}\n"
+               file_out.write "\tsuper JavaObject\n\nend\n"
        end
 
-       fun gen_attribute(jid: String, jtype: JavaType): String
-       do
-               return "\tvar {jid.to_snake_case}: {jtype.to_nit_type}\n"
-       end
-       
-       fun gen_method(jmethod_id: String, nmethod_id: String, jreturn_type: JavaType, jparam_list: Array[JavaType]): String
+       private fun generate_method(java_class: JavaClass, java_method_id, method_id: String,
+               java_return_type: JavaType, java_params: Array[JavaType], is_static: nullable Bool)
        do
-               var java_params = ""
-               var nit_params  = ""
+               var java_args = new Array[String]
+               var nit_params = new Array[String]
                var nit_id = "arg"
                var nit_id_no = 0
-               var nit_types = new Array[NitType]
-               var comment = "" 
+               var c = ""
 
                # Parameters
-               for i in [0..jparam_list.length[ do
-                       var jparam = jparam_list[i]
-                       var nit_type = jparam.to_nit_type
-
-                       if not nit_type.is_complete then
-                               if jparam.is_wrapped then
-                                       java_class.imports.add nit_type.mod.as(not null)
-                               else
-                                       if comment_unknown_types then
-                                               comment = "#"
-                                       else
-                                               nit_type = jparam.extern_name
-                                               java_class.unknown_types.add(jparam)
-                                       end
-                               end
-                       end
+               for jparam in java_params do
+                       var nit_type = model.java_to_nit_type(jparam)
 
-                       var cast = ""
+                       if not nit_type.is_known and comment_unknown_types then c = "#"
 
-                       if not jparam.is_collection then cast = jparam.param_cast
-
-                       nit_types.add(nit_type)
-                       nit_type.arg_id = "{nit_id}{nit_id_no}"
-
-                       if i == jparam_list.length - 1 then
-                               java_params += "{cast}{nit_id}{nit_id_no}"
-                               nit_params  += "{nit_id}{nit_id_no}: {nit_type}"
-                       else
-                               java_params += "{cast}{nit_id}{nit_id_no}" + ", "
-                               nit_params  += "{nit_id}{nit_id_no}: {nit_type}, "
-                       end
+                       java_args.add "{jparam.param_cast}{nit_id}{nit_id_no}"
+                       nit_params.add "{nit_id}{nit_id_no}: {nit_type}"
 
                        nit_id_no += 1
                end
 
                # Method identifier
-               var method_id = nmethod_id.to_snake_case
-               var nit_signature = new Array[String]
-
-               nit_signature.add "\tfun {method_id}"
+               method_id = method_id.to_nit_method_name
+               method_id = java_class.nit_name_for(method_id, java_params, java_class.methods[java_method_id].length > 1)
 
-               if not jparam_list.is_empty then
-                       nit_signature.add "({nit_params})"
-               end
+               # Build the signature
+               var nit_signature = new Array[String]
+               nit_signature.add "fun {method_id}"
+               if not java_params.is_empty then nit_signature.add "({nit_params.join(", ")})"
 
+               # Return value
                var return_type = null
+               if not java_return_type.is_void then
+                       return_type = model.java_to_nit_type(java_return_type)
 
-               if not jreturn_type.is_void then
-                       return_type = jreturn_type.to_nit_type
-
-                       if not return_type.is_complete then
-                               if jreturn_type.is_wrapped then
-                                       java_class.imports.add return_type.mod.as(not null)
-                               else
-                                       if comment_unknown_types then
-                                               comment = "#"
-                                       else
-                                               return_type = jreturn_type.extern_name
-                                               java_class.unknown_types.add(jreturn_type)
-                                       end
-                               end
-                       end
+                       if not return_type.is_known and comment_unknown_types then c = "#"
 
-                       nit_signature.add ": {return_type} "
+                       nit_signature.add ": " + return_type.to_s
                end
 
-               var param_to_copy = param_to_copy(jparam_list, nit_types)
-
-               var temp = new Array[String]
-
-               if nb_params > 1 then
-                       comment = "#"
-                       temp.add("\t# NOT SUPPORTED: more than one parameter to copy\n")
-                       temp.add("\t# Has to be implemented manually\n")
-               end
-
-               temp.add(comment + nit_signature.join(""))
-
-               # FIXME : This huge `if` block is only necessary to copy primitive arrays as long as there's no better way to do it
-               if comment == "#" then
-                       temp.add(" in \"Java\" `\{\n{comment}\t\trecv.{jmethod_id}({java_params});\n{comment}\t`\}\n")
-               # Methods with return type
-               else if return_type != null then
-                       if jreturn_type.is_primitive_array then
-                               # Copy one parameter and the return value
-                               if param_to_copy != null then
-                                       var rtype_couple = new Couple[JavaType, NitType](jreturn_type, return_type)
-                                       temp.add(code_warehouse.param_return_copy(rtype_couple, param_to_copy, jmethod_id, java_params))
-                               # Copy the return type
-                               else
-                                       temp.add(code_warehouse.return_type_copy(jreturn_type, return_type, jmethod_id, java_params))
-                               end
-                       # Copy the parameter
-                       else if param_to_copy != null then
-                               temp.add(code_warehouse.param_type_copy(param_to_copy.first, param_to_copy.second, jmethod_id, java_params, true))
-                       # No copy
-                       else
-                               temp.add(" in \"Java\" `\{\n{comment}\t\treturn {jreturn_type.return_cast} recv.{jmethod_id}({java_params});\n{comment}\t`\}\n")
-                       end
-               # Methods without return type
-               else if jreturn_type.is_void then
-                       # Copy one parameter
-                       if param_to_copy != null then
-                               temp.add(code_warehouse.param_type_copy(param_to_copy.first, param_to_copy.second, jmethod_id, java_params, false))
-                       # No copy
-                       else
-                               temp.add(" in \"Java\" `\{\n{comment}\t\trecv.{jmethod_id}({java_params});\n{comment}\t`\}\n")
-                       end
-               # No copy
-               else
-                       temp.add(" in \"Java\" `\{\n{comment}\t\trecv.{jmethod_id}({java_params});\n{comment}\t`\}\n")
-               end
-
-               return temp.join("")
+               # Build the call in Java
+               var java_call
+               if is_static == true then
+                       java_call = java_class.class_type.package_name
+               else java_call = "self"
+               java_call += ".{java_method_id}({java_args.join(", ")})"
+
+               if return_type != null then java_call = "return {java_return_type.return_cast}" + java_call
+
+               # Tabulation
+               var t = "\t"
+               if is_static == true then t = ""
+               var ct = c+t
+
+               # Write
+               file_out.write """
+{{{t}}}# Java implementation: {{{java_return_type}}} {{{java_class}}}.{{{java_method_id}}}({{{java_params.join(", ")}}})
+{{{ct}}}{{{nit_signature.join}}} in "Java" `{
+{{{ct}}}       {{{java_call}}};
+{{{ct}}}`}
+"""
        end
 
-       # Only one primitive array parameter can be copied
-       # If there's none or more than one then `null` is returned
-       fun param_to_copy(jtypes: Array[JavaType], ntypes: Array[NitType]): nullable Couple[JavaType, NitType]
+       # Generate getter and setter to access an attribute, of field
+       private fun generate_getter_setter(java_class: JavaClass, java_id: String,
+               attribute: JavaAttribute)
        do
-               var counter = 0
-               var couple = null
-               for i in [0..jtypes.length[ do
-                       if jtypes[i].is_primitive_array then
-                               counter += 1
-                               couple = new Couple[JavaType, NitType](jtypes[i], ntypes[i])
-                       end
-               end
-
-               nb_params = counter
+               var java_type = attribute.java_type
+               var nit_type = model.java_to_nit_type(java_type)
+
+               var nit_id = java_id
+               if attribute.is_static then nit_id = java_class.class_type.extern_name.to_snake_case + "_" + nit_id
+               nit_id = nit_id.to_nit_method_name
+               nit_id = java_class.nit_name_for(nit_id, [java_type], false)
+
+               var c = ""
+               if not nit_type.is_known and comment_unknown_types then c = "#"
+
+               var recv
+               if attribute.is_static then
+                       recv = java_class.class_type.package_name
+               else recv = "self"
+
+               # Tabulation
+               var t = "\t"
+               if attribute.is_static then t = ""
+               var ct = c+t
+
+               file_out.write """
+{{{t}}}# Java getter: {{{java_class}}}.{{{java_id}}}
+{{{ct}}}fun {{{nit_id}}}: {{{nit_type}}} in "Java" `{
+{{{ct}}}       return {{{recv}}}.{{{java_id}}};
+{{{ct}}}`}
+
+{{{t}}}# Java setter: {{{java_class}}}.{{{java_id}}}
+{{{ct}}}fun {{{nit_id}}}=(value: {{{nit_type}}}) in "Java" `{
+{{{ct}}}       {{{recv}}}.{{{java_id}}} = value;
+{{{ct}}}`}
 
-               if counter > 1 then return null
-               return couple
+"""
        end
-end
-
-# Contains raw code mostly used to copy collections
-class CodeWarehouse
 
-       # Collection as return value
-       fun return_type_copy(java_type: JavaType, nit_type: NitType, jmethod_id, params_id: String): String
+       # Generate getter and setter to access an attribute, of field
+       private fun generate_constructor(java_class: JavaClass, constructor: JavaConstructor, name: String)
        do
-               var narray_id = "nit_array"
-               var loop_ = create_loop(java_type, nit_type, false, "java_array", narray_id)
-               var imports = create_imports(nit_type, false)
+               var c = ""
+               var nit_params_s = ""
+               var java_params_s = ""
 
-               return """{{{imports}}} in "Java" `{ 
-               {{{java_type.to_s}}} java_array = recv.{{{jmethod_id}}}({{{params_id}}});
-               int {{{narray_id}}} = new_{{{nit_type.id}}}_of_{{{nit_type.generic_params.join("_")}}}();
+               if constructor.params.not_empty then
+                       var nit_params = new Array[String]
+                       var java_params = new Array[String]
+                       var param_id = 'a'
+                       for java_type in constructor.params do
 
-               {{{loop_}}}
+                               java_params.add "{java_type.param_cast}{param_id}"
 
-               return {{{narray_id}}};
-       `}
-"""
-       end
+                               var nit_type = model.java_to_nit_type(java_type)
+                               nit_params.add  "{param_id}: {nit_type}"
+                               param_id = param_id.successor(1)
 
-       # Collection as parameter
-       fun param_type_copy(java_type: JavaType, nit_type: NitType, jmethod_id, params_id: String, has_return: Bool): String
-       do
-               var narray_id = "nit_array"
-               var jarray_id = "java_array"
-               var loop_ = create_loop(java_type, nit_type, true, jarray_id, narray_id)
-               var imports = create_imports(nit_type, true)
-               var jtype = java_type.to_s
-               var jinstanciation = create_array_instance(java_type, nit_type, jarray_id)
-               var return_str = ""
-               
-               if has_return then
-                       return_str = "return "
-               end
-
-               params_id = params_id.replace(nit_type.arg_id, jarray_id)
+                               if not nit_type.is_known and comment_unknown_types then c = "#"
+                       end
 
-               return """{{{imports}}} in "Java" `{ 
-               {{{jinstanciation}}}
-               int {{{narray_id}}} = new_{{{nit_type.id}}}_of_{{{nit_type.generic_params.join("_")}}}();
+                       nit_params_s = "(" + nit_params.join(", ") + ")"
+                       java_params_s = java_params.join(", ")
+               end
 
-               {{{loop_}}}
+               file_out.write """
+       # Java constructor: {{{java_class}}}
+{{{c}}}        new {{{name}}}{{{nit_params_s}}} in "Java" `{
+{{{c}}}                return new {{{java_class}}}({{{java_params_s}}});
+{{{c}}}        `}
 
-               {{{return_str}}}recv.{{{jmethod_id}}}({{{params_id}}});
-       `}
 """
        end
 
-       # One collection parameter and the return type will be copied
-       fun param_return_copy(return_types, param_types: Couple[JavaType, NitType], jmethod_id, params_id: String): String
+       private fun generate_primitive_array(java_class: JavaClass, dimensions: Int)
        do
-               var narray_id = "nit_array"
-               var narray_id2 = "nit_array2"
+               var base_java_type = java_class.class_type
+               var java_type = base_java_type.clone
+               java_type.array_dimension = dimensions
 
-               var r_jtype = return_types.first
-               var r_ntype = return_types.second
+               var base_nit_type = model.java_to_nit_type(base_java_type)
+               var nit_type = model.java_to_nit_type(java_type)
 
-               var p_jtype = param_types.first
-               var p_ntype = param_types.second
+               file_out.write """
+# Java primitive array: {{{java_type}}}
+extern class {{{nit_type}}} in "Java" `{ {{{java_type.extern_equivalent}}} `}
+       super AbstractJavaArray[{{{base_nit_type}}}]
 
-               var r_loop = create_loop(r_jtype, r_ntype, false, "java_array", narray_id)
-               var p_loop = create_loop(p_jtype, p_ntype, true, "java_array2", narray_id2)
+       # Get a new array of the given `size`
+       new(size: Int) in "Java" `{ return new {{{base_java_type}}}[(int)size]; `}
 
-               var imports = new Array[String]
-               
-               # Avoid import duplication
-               if p_ntype.to_s != r_ntype.to_s then
-                       imports.add create_imports(p_ntype, true)
-               end
-
-               imports.add create_imports(r_ntype, false)
+       redef fun [](i) in "Java" `{ return self[(int)i]; `}
 
-               params_id = params_id.replace(p_ntype.arg_id, narray_id)
+       redef fun []=(i, e) in "Java" `{ self[(int)i] = e; `}
 
-               var jinstanciation = create_array_instance(p_jtype, p_ntype, "java_array")
+       redef fun length in "Java" `{ return self.length; `}
 
-               return """{{{imports.join(", ")}}} in "Java" `{
-               {{{jinstanciation}}}
+"""
+               generate_jni_services(java_type)
+               file_out.write """
+end
 
-               {{{p_loop}}}
+"""
+       end
 
-               {{{r_jtype.to_s}}} java_array2 = recv.{{{jmethod_id}}}({{{params_id}}});
-               int {{{narray_id2}}} = new_{{{r_ntype.id}}}_of_{{{r_ntype.generic_params.join("_")}}}();
+       # Generate JNI related services
+       #
+       # For now, mostly avoid issue #845, but more services could be generated as needed.
+       private fun generate_jni_services(java_type: JavaType)
+       do
+               var nit_type = model.java_to_nit_type(java_type)
 
-               {{{r_loop}}}
+               file_out.write """
+       redef fun new_global_ref import sys, Sys.jni_env `{
+               Sys sys = {{{nit_type}}}_sys(self);
+               JNIEnv *env = Sys_jni_env(sys);
+               return (*env)->NewGlobalRef(env, self);
+       `}
 
-               return {{{narray_id2}}};
+       redef fun pop_from_local_frame_with_env(jni_env) `{
+               return (*jni_env)->PopLocalFrame(jni_env, self);
        `}
 """
        end
+end
+
+redef class Sys
+       # List of Nit keywords
+       #
+       # These may also be keywords in Java, but there they would be used capitalized.
+       private var nit_keywords = new HashSet[String].from(["abort", "abstract", "and", "assert",
+               "break", "class", "continue", "do", "else", "end", "enum", "extern", "false", "implies",
+               "import", "init", "interface", "intrude", "if", "in", "is", "isa", "isset", "for", "label",
+               "loop", "module", "new", "not", "null", "nullable", "or", "package", "private",
+               "protected", "public", "return", "self", "super", "then", "true", "type", "var", "while",
+
+       # Top-level methods
+               "class_name", "get_time", "hash", "is_same_type", "is_same_instance", "output",
+
+       # Pointer or JavaObject methods
+               "free"])
+end
+
+redef class String
 
-       private fun create_array_instance(java_type: JavaType, nit_type: NitType, jarray_id: String): String
+       # Convert the Java method name `self` to the Nit style
+       #
+       # * Converts to snake case
+       # * Strips `Get` and `Set`
+       # * Add suffix `=` to setters
+       fun to_nit_method_name: String
        do
-               var jtype = java_type.to_s
-               var instanciation = ""
+               var name = self.to_snake_case
 
-               if java_type.is_primitive_array then
-                       instanciation = "{jtype} {jarray_id} = new {java_type.full_id}[(int)Array_of_{nit_type.generic_params[0]}_length({nit_type.arg_id})];"
-               else
-                       instanciation = "{jtype} {jarray_id} = new {jtype}();"
-               end
+               # Strip the '_' prefix
+               while name.has_prefix("_") do name = name.substring(1, name.length-1)
+
+               # Escape Nit keywords
+               if nit_keywords.has(name) then name += "_"
+
+               # If the name starts by something other than a letter, prefix with `java_`
+               if not name.chars.first.is_letter then name = "java_" + name
 
-               return instanciation
+               name = name.replace("$", "_")
+
+               return name
        end
+end
+
+redef class JavaClass
+       # Property names used in this class
+       private var used_name = new HashSet[String]
 
-       private fun create_imports(nit_type: NitType, is_param: Bool): String
+       # Get an available property name for the Java property with `name` and parameters
+       #
+       # If `use_parameters_name` then expect that there will be conflicts,
+       # so use the types of `parameters` to build the name.
+       private fun nit_name_for(name: String, parameters: Array[JavaType], use_parameters_name: Bool): String
        do
-               var imports = ""
-               var ntype = nit_type.to_s
-               var gen_type = nit_type.generic_params.join(", ")
-
-               if not is_param then
-                       if nit_type.is_map then
-                               imports = """ import {{{ntype}}}, {{{ntype}}}.[]="""
-                       else
-                               imports = """ import {{{ntype}}}, {{{ntype}}}.add"""
+               # Append the name of each parameter
+               if use_parameters_name then
+                       for param in parameters do
+                               name += "_" + param.id
                        end
-               else if nit_type.id == "Array" then
-                       imports = """ import {{{ntype}}}, {{{ntype}}}.length, {{{ntype}}}.[]"""
-               else if nit_type.is_map then
-                       imports = """ import {{{ntype}}}.iterator, Iterator[{{{gen_type}}}].is_ok, Iterator[{{{gen_type}}}].next, Iterator[{{{gen_type}}}].item, Iterator[{{{gen_type}}}].key"""
-               else
-                       imports = """ import {{{ntype}}}.iterator, Iterator[{{{gen_type}}}].is_ok, Iterator[{{{gen_type}}}].next, Iterator[{{{gen_type}}}].item"""
                end
-               
-               return imports
-       end
 
-       private fun create_loop(java_type: JavaType, nit_type: NitType, is_param: Bool, jarray_id, narray_id: String): String
-       do
-               var loop_header = ""
-               var loop_body = ""
-               var gen_type = nit_type.generic_params.join("_")
-
-               if is_param then
-                       if java_type.is_primitive_array then
-                               loop_header = "for(int i=0; i < {jarray_id}.length; ++i)"
-                               loop_body   = """\t\t\t{{{jarray_id}}}[i] = {{{java_type.param_cast}}}Array_of_{{{gen_type}}}__index({{{nit_type.arg_id}}}, i);"""
-                       else if nit_type.id == "Array" then
-                               loop_header = """int length = Array_of_{{{gen_type}}}_length((int){{{nit_type.arg_id}}});\n\t\tfor(int i=0; i < length; ++i)"""
-                               loop_body   = """\t\t\t{{{jarray_id}}}.add({{{java_type.param_cast}}}Array_of_{{{gen_type}}}__index({{{narray_id}}}, i));"""
-                       else
-                               loop_header = """int itr = {{{nit_type.id}}}_of_{{{gen_type}}}_iterator({{{nit_type.arg_id}}});\n\t\twhile(Iterator_of_{{{gen_type}}}_is_ok(itr)) {"""
-                               if nit_type.is_map then
-                                       var key_cast = java_type.to_cast(java_type.generic_params[0].id, true)
-                                       var value_cast = java_type.to_cast(java_type.generic_params[1].id, true)
-                                       loop_body   = """\t\t\t{{{jarray_id}}}[{{{key_cast}}}iterator_of_{{{nit_type.id}}}_key(itr)] = {{{value_cast}}}iterator_of_{{{nit_type.id}}}_item(itr);\n\t\t\titerator_of_{{{gen_type}}}_next(itr);\n\t\t}"""
-                               else
-                                       loop_body   = """\t\t\t{{{jarray_id}}}.add({{{java_type.param_cast}}}iterator_of_{{{nit_type.id}}}_item(itr));\n\t\t\titerator_of_{{{gen_type}}}_next(itr);\n\t\t}"""
-                               end
-                       end
-               else
-                       if nit_type.is_map then
-                               var key_cast = java_type.to_cast(java_type.generic_params[0].id, false)
-                               var value_cast = java_type.to_cast(java_type.generic_params[1].id, false)
-                               loop_header = """for (java.util.Map.Entry<{{{java_type.generic_params[0]}}}, {{{java_type.generic_params[1]}}}> e: {{{jarray_id}}})"""
-                               loop_body   = """\t\t\t{{{nit_type.id}}}_of_{{{gen_type}}}_{{{nit_type.generic_params[1]}}}__index_assign({{{narray_id}}}, {{{key_cast}}}e.getKey(), {{{value_cast}}}e.getValue());"""
-                       else if java_type.is_iterable then
-                               loop_header = """for ({{{java_type.generic_params[0]}}} e: {{{jarray_id}}})"""
-                               loop_body   = """\t\t\t{{{nit_type.id}}}_of_{{{gen_type}}}_add({{{narray_id}}}, {{{java_type.return_cast}}}e);"""
-                       else
-                               loop_header = "for(int i=0; i < {jarray_id}.length; ++i)"
-                               loop_body   = """\t\t\t{{{nit_type.id}}}_of_{{{gen_type}}}_add({{{narray_id}}}, {{{java_type.return_cast}}}{{{jarray_id}}}[i]);"""
-                       end
+               # As a last resort, append numbers to the name
+               var base_name = name
+               var count = 1
+               while used_name.has(name) do
+                       name = base_name + count.to_s
+                       count += 1
                end
 
-               return loop_header + "\n" + loop_body
+               used_name.add name
+               return name
        end
 end