org.codehaus.janino
Class ClassBodyEvaluator

java.lang.Object
  org.codehaus.janino.EvaluatorBase
      org.codehaus.janino.ClassBodyEvaluator

public class ClassBodyEvaluator

extends EvaluatorBase

Parses a class body and returns it as a java.lang.Class object ready for use with java.lang.reflect.

Example:

   import java.util.*;

   static private int a = 1;
   private int b = 2;

   public void func(int c, int d) {
       return func2(c, d);
   }

   private static void func2(int e, int f) {
       return e * f;
   }
 

Constructor Summary

ClassBodyEvaluator(Scanner scanner, Class optionalExtendedType, Class[] implementedTypes, ClassLoader optionalParentClassLoader)
See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

ClassBodyEvaluator(Scanner scanner, ClassLoader optionalParentClassLoader)
See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

ClassBodyEvaluator(Scanner scanner, String className, Class optionalExtendedType, Class[] implementedTypes, ClassLoader optionalParentClassLoader)
Parse and compile a class body, i.e.

ClassBodyEvaluator(String classBody)
See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

ClassBodyEvaluator(String optionalFileName, InputStream is)
See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

ClassBodyEvaluator(String optionalFileName, Reader reader)
See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

Method Summary

static Object	createFastClassBodyEvaluator(Scanner scanner, Class optionalBaseType, ClassLoader optionalClassLoader) Compiles a class body and instantiates it.
static Object	createFastClassBodyEvaluator(Scanner scanner, String className, Class optionalExtendedType, Class[] implementedTypes, ClassLoader optionalParentClassLoader) Like createFastClassBodyEvaluator(Scanner, Class, ClassLoader), but gives you more control over the generated class (rarely needed in practice).
Class	evaluate() Returns the java.lang.Class object compiled from the class body.

Methods inherited from class org.codehaus.janino.EvaluatorBase

addClassMethodBlockDeclaration, addPackageMemberClassDeclaration, classesToTypes, classToType, compileAndLoad, compileAndLoad, makeFormalParameters, parseImportDeclarations

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ClassBodyEvaluator

public ClassBodyEvaluator(String classBody)
                   throws CompileException,
                          Parser.ParseException,
                          Scanner.ScanException

See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

ClassBodyEvaluator

public ClassBodyEvaluator(String optionalFileName,
                          InputStream is)
                   throws CompileException,
                          Parser.ParseException,
                          Scanner.ScanException,
                          IOException

See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

ClassBodyEvaluator

public ClassBodyEvaluator(String optionalFileName,
                          Reader reader)
                   throws CompileException,
                          Parser.ParseException,
                          Scanner.ScanException,
                          IOException

See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

ClassBodyEvaluator

public ClassBodyEvaluator(Scanner scanner,
                          ClassLoader optionalParentClassLoader)
                   throws CompileException,
                          Parser.ParseException,
                          Scanner.ScanException,
                          IOException

See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

ClassBodyEvaluator

public ClassBodyEvaluator(Scanner scanner,
                          Class optionalExtendedType,
                          Class[] implementedTypes,
                          ClassLoader optionalParentClassLoader)
                   throws CompileException,
                          Parser.ParseException,
                          Scanner.ScanException,
                          IOException

See ClassBodyEvaluator(Scanner, String, Class, Class[], ClassLoader).

ClassBodyEvaluator

public ClassBodyEvaluator(Scanner scanner,
                          String className,
                          Class optionalExtendedType,
                          Class[] implementedTypes,
                          ClassLoader optionalParentClassLoader)
                   throws CompileException,
                          Parser.ParseException,
                          Scanner.ScanException,
                          IOException

Parse and compile a class body, i.e. a series of member definitions.

The optionalClassLoader serves two purposes:

• It is used to look for classes referenced by the class body.
• It is used to load the generated Java^TM class into the JVM; directly if it is a subclass of ByteArrayClassLoader, or by creation of a temporary ByteArrayClassLoader if not.

A number of constructors exist that provide useful default values for the various parameters, or parse the class body from a String, an InputStream or a Reader instead of a Scanner.

Parameters:

scanner - Source of tokens

className - The name of the temporary class (uncritical)

optionalExtendedType - Class to extend or null

implementedTypes - Interfaces to implement

optionalParentClassLoader - Loads referenced classes

Method Detail

createFastClassBodyEvaluator

public static Object createFastClassBodyEvaluator(Scanner scanner,
                                                  Class optionalBaseType,
                                                  ClassLoader optionalClassLoader)
                                           throws CompileException,
                                                  Parser.ParseException,
                                                  Scanner.ScanException,
                                                  IOException

Compiles a class body and instantiates it. The generated class may optionally extend/implement a given type. The returned instance can safely be type-casted to that optionalBaseType.

Example:

 public interface Foo {
     int bar(int a, int b);
 }
 ...
 Foo f = (Foo) ClassBodyEvaluator.createFastClassBodyEvaluator(
     new Scanner(null, new StringReader("public int bar(int a, int b) { return a + b; }")),
     Foo.class,
     (ClassLoader) null          // Use current thread's context class loader
 );
 System.out.println("1 + 2 = " + f.bar(1, 2));
 

Notice: The optionalBaseType must either be declared public, or with package scope in the root package (i.e. "no" package).

Parameters:

scanner - Source of class body tokens

optionalBaseType - Base type to extend/implement (see above)

optionalClassLoader -

Returns:

an object that extends/implements the given optionalBaseType

Throws:

CompileException

Parser.ParseException

Scanner.ScanException

IOException

createFastClassBodyEvaluator

public static Object createFastClassBodyEvaluator(Scanner scanner,
                                                  String className,
                                                  Class optionalExtendedType,
                                                  Class[] implementedTypes,
                                                  ClassLoader optionalParentClassLoader)
                                           throws CompileException,
                                                  Parser.ParseException,
                                                  Scanner.ScanException,
                                                  IOException

Like createFastClassBodyEvaluator(Scanner, Class, ClassLoader), but gives you more control over the generated class (rarely needed in practice).

Notice: The optionalExtendedType and the implementedTypes must either be declared public, or with package scope in the same package as className.

Parameters:

scanner - Source of class body tokens

className - Name of generated class

optionalExtendedType - Class to extend

implementedTypes - Interfaces to implement

optionalParentClassLoader - Loads referenced classes

Returns:

an object that extends the optionalExtendedType and implements the given implementedTypes

Throws:

CompileException

Parser.ParseException

Scanner.ScanException

IOException

evaluate

public Class evaluate()

Returns the java.lang.Class object compiled from the class body.