//1 generate a model
_class _model = _class.of( "package mymodel;",
"public class Model" )
.imports( UUID.class )
.method( "public String createId()",
"return UUID.randomUUID().toString();" );
// 2) create instance
Object dynamicModel = _model.instance();
// 3) call a method on the dynamic instance
String id1 = (String)Java.call( dynamicModel, "createId" );
// 4) export .java & .class files:
// export "C:\MyApp\src\main\java\mymodel\Model.java"
Export.dir( "C:\\MyApp\\src\\main\\java\\").toFile( _model );
// export "C:\MyApp\traget\classes\mymodel\Model.class"
Export.dir( "C:\\MyApp\\target\\classes\\").toFile( dynamicModel.getClass() );...Export( "C:\\MyApp\\src\\main\\java\\").toFile( _model ); will create the file C:\\myapp\\src\\main\\java\\mymodel\\Model.java containing:
package mymodel;
import java.util.UUID;
public class Model
{
public String createId( )
{
return UUID.randomUUID().toString();
}
}varcode makes metaprogramming easy. load a ( _class, _enum, _interface, _annotationType ) from an existing class, modify it at the source level, then compile & use it at runtime (no restarting required).
// 1. build the _class model from the .java source of the Class
_class _c = Java._classFrom( OriginalClass.class );
// 2. modify the model
_c.setName("Tailored");// change the class Name
_c.field("private static final int ID = 100;"); // add field
// get and modify the "toString" method
_c.getMethod("toString").body( "return getClass().getSimpleName() + ID;")
// 3. compile, instantiate and use it
Object tailored = _c.instance(); // create a new instance of "Tailored"
System.out.println( tailored ); //prints "Tailored100"classes for ( _class, _interface, _enum, _annotationType ) can be built in a single compound statement or incrementally using simple mutator methods.
_class _c = _class.of( "package ex.mutable;",
_imports.of( Serializable.class ),
"@Deprecated",
"public class MyMutableModel implements Serializable" );
_method _m = _method.of( "/** create a random number */",
"@Generated",
"public static final double random()",
"return Math.random();" );
_c.method( _m ); //add the "random" method to the _class
_field _f = _field.of( "/** field javadoc */",
"public static int ID = 100;");
_c.add( _f ); //add the "ID" field to the _class