org.codehaus.commons.compiler.IClassBodyEvaluator Maven / Gradle / Ivy
/*
* Janino - An embedded Java[TM] compiler
*
* Copyright (c) 2001-2010, Arno Unkrig
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
* following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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*/
package org.codehaus.commons.compiler;
import java.io.IOException;
import java.io.Reader;
/**
* Parses a class body and returns it as a {@link 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;
* }
*
*
* To set up an {@link IClassBodyEvaluator} object, proceed as follows:
*
* -
* Create an {@link IClassBodyEvaluator}-implementing class.
*
-
* Configure the {@link IClassBodyEvaluator} by calling any of the following methods:
*
* - {@link #setDefaultImports(String[])}
*
- {@link #setClassName(String)}
*
- {@link #setExtendedClass(Class)}
*
- {@link #setImplementedInterfaces(Class[])}
*
- {@link #setParentClassLoader(ClassLoader)}
*
* -
* Call any of the {@link ICookable#cook(String, java.io.Reader)} methods to scan,
* parse, compile and load the class body into the JVM.
*
* To compile a class body and immediately instantiate an object, the {@link #createInstance(Reader)} methods can be
* used.
*
* 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);
* }
* ...
* {@link IClassBodyEvaluator} cbe = {@link CompilerFactoryFactory}.{@link
* CompilerFactoryFactory#getDefaultCompilerFactory() getDefaultCompilerFactory}(). {@link
* ICompilerFactory#newClassBodyEvaluator() newClassBodyEvaluator}();
* Foo f = (Foo) ClassBodyEvaluator.createFastClassBodyEvaluator(
* new Scanner(null, new StringReader("public int bar(int a, int b) { return a + b; }")),
* Foo.class, // Base type to extend/implement
* (ClassLoader) null // Use current thread's context class loader
* );
* System.out.println("1 + 2 = " + f.bar(1, 2));
*
*/
@SuppressWarnings("rawtypes") public
interface IClassBodyEvaluator extends ICookable {
/** Default name for the generated class. */
String DEFAULT_CLASS_NAME = "SC";
/**
* "Default imports" add to the system import "java.lang", i.e. the evaluator may refer to
* classes imported by default imports without having to explicitly declare IMPORT statements.
*
* Notice that JDK 5 "static imports" are also supported, as shown in the following example.
*
* Example:
* sc.setDefaultImports(new String[] {
* "java.util.Map", // Single type import
* "java.io.*", // Type-import-on-demand
* "static java.util.Collections.EMPTY_MAP", // Single static import
* "static java.util.Collections.*", // Static-import-on-demand
* });
*/
void setDefaultImports(String[] optionalDefaultImports);
/**
* Set the name of the generated class. Defaults to {@link #DEFAULT_CLASS_NAME}. In most cases,
* there is no need to set this name, because the generated class is loaded into its own
* {@link java.lang.ClassLoader} where its name cannot collide with classes generated by
* other evaluators.
*
* One reason to use this function is to have a class name in a non-default package, which
* can be relevant when types and members with DEFAULT accessibility are accessed.
*/
void setClassName(String className);
/**
* Set a particular superclass that the generated class will extend. If null is
* passed, the generated class will extend {@link Object}.
*
* The common reason to set a base class for an evaluator is that the generated class can
* directly access the base superclass's (non-private) members.
*/
void setExtendedClass(Class optionalExtendedClass);
/** @deprecated Use {@link #setExtendedClass(Class)} instead. */
@Deprecated void setExtendedType(Class optionalExtendedClass);
/** Set a particular set of interfaces that the generated class will implement. */
void setImplementedInterfaces(Class[] implementedInterfaces);
/** @deprecated Use {@link #setImplementedInterfaces(Class[])} instead. */
@Deprecated void setImplementedTypes(Class[] implementedInterfaces);
/**
* Returns the loaded {@link Class}.
*
* This method must only be called after exactly one of the {@link #cook(String,
* java.io.Reader)} methods was called.
*/
Class getClazz();
/**
* Scans, parses and compiles a class body from the tokens delivered by the the given {@link Reader}, then creates
* and returns an instance of that class.
*
* @param reader Source of class body tokens
* @return An object that extends the optionalExtendedType and implements the given
* implementedTypes
*/
Object createInstance(Reader reader) throws CompileException, IOException;
}