Java tutorial
/** * * Copyright 2010-2011 (C) The original author or authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.toolazydogs.aunit.internal; import com.toolazydogs.aunit.LexerSetup; import org.antlr.runtime.CharStream; import org.antlr.runtime.Lexer; import org.antlr.runtime.RecognizerSharedState; import org.objectweb.asm.ClassWriter; import org.objectweb.asm.FieldVisitor; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.Opcodes; import java.lang.reflect.Constructor; /** * */ public class LexerFactory<L extends Lexer> implements Opcodes { private final Class<L> lexerClass; private final LexerSetup<L> lexerSetup; private final boolean failOnError; private Class<L> wrapperClass; public LexerFactory(Class<L> lexerClass, boolean failOnError, LexerSetup<L> lexerSetup) { this.lexerClass = lexerClass; this.failOnError = failOnError; this.lexerSetup = lexerSetup; } public Lexer generate() throws Exception { return getWrapperClass().newInstance(); } public Lexer generate(CharStream input) throws Exception { Class<L> wc = getWrapperClass(); Constructor c = wc.getConstructor(CharStream.class); LexerWrapper wrapper = (LexerWrapper) c.newInstance(input); if (lexerSetup != null) { lexerSetup.config((L) wrapper); } wrapper.setFailOnError(failOnError); return (Lexer) wrapper; } public Lexer generate(CharStream input, RecognizerSharedState state) throws Exception { Class<? extends Lexer> wc = getWrapperClass(); Constructor c = wc.getConstructor(CharStream.class, RecognizerSharedState.class); LexerWrapper wrapper = (LexerWrapper) c.newInstance(input, state); if (lexerSetup != null) { lexerSetup.config((L) wrapper); } wrapper.setFailOnError(failOnError); return (Lexer) wrapper; } private Class<L> getWrapperClass() { if (wrapperClass == null) wrapperClass = loadClass(); return wrapperClass; } private Class<L> loadClass() { final String parent = lexerClass.getName().replace('.', '/'); final String name = "com/toolazydogs/aunit/asm/" + parent; ClassWriter cw = new ClassWriter(0); FieldVisitor fv; MethodVisitor mv; cw.visit(V1_5, ACC_PUBLIC + ACC_SUPER, name, null, parent, new String[] { "com/toolazydogs/aunit/internal/LexerWrapper" }); { fv = cw.visitField(ACC_PRIVATE + ACC_FINAL, "errors", "Ljava/util/List;", "Ljava/util/List<Ljava/lang/String;>;", null); fv.visitEnd(); } { fv = cw.visitField(ACC_PRIVATE, "failOnError", "Z", null, null); fv.visitEnd(); } { mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null); mv.visitCode(); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKESPECIAL, parent, "<init>", "()V"); mv.visitVarInsn(ALOAD, 0); mv.visitTypeInsn(NEW, "java/util/ArrayList"); mv.visitInsn(DUP); mv.visitMethodInsn(INVOKESPECIAL, "java/util/ArrayList", "<init>", "()V"); mv.visitFieldInsn(PUTFIELD, name, "errors", "Ljava/util/List;"); mv.visitVarInsn(ALOAD, 0); mv.visitInsn(ICONST_1); mv.visitFieldInsn(PUTFIELD, name, "failOnError", "Z"); mv.visitInsn(RETURN); mv.visitMaxs(3, 1); mv.visitEnd(); } { mv = cw.visitMethod(ACC_PUBLIC, "<init>", "(Lorg/antlr/runtime/CharStream;)V", null, null); mv.visitCode(); mv.visitVarInsn(ALOAD, 0); mv.visitVarInsn(ALOAD, 1); mv.visitMethodInsn(INVOKESPECIAL, parent, "<init>", "(Lorg/antlr/runtime/CharStream;)V"); mv.visitVarInsn(ALOAD, 0); mv.visitTypeInsn(NEW, "java/util/ArrayList"); mv.visitInsn(DUP); mv.visitMethodInsn(INVOKESPECIAL, "java/util/ArrayList", "<init>", "()V"); mv.visitFieldInsn(PUTFIELD, name, "errors", "Ljava/util/List;"); mv.visitVarInsn(ALOAD, 0); mv.visitInsn(ICONST_1); mv.visitFieldInsn(PUTFIELD, name, "failOnError", "Z"); mv.visitInsn(RETURN); mv.visitMaxs(3, 2); mv.visitEnd(); } { mv = cw.visitMethod(ACC_PUBLIC, "<init>", "(Lorg/antlr/runtime/CharStream;Lorg/antlr/runtime/RecognizerSharedState;)V", null, null); mv.visitCode(); mv.visitVarInsn(ALOAD, 0); mv.visitVarInsn(ALOAD, 1); mv.visitVarInsn(ALOAD, 2); mv.visitMethodInsn(INVOKESPECIAL, parent, "<init>", "(Lorg/antlr/runtime/CharStream;Lorg/antlr/runtime/RecognizerSharedState;)V"); mv.visitVarInsn(ALOAD, 0); mv.visitTypeInsn(NEW, "java/util/ArrayList"); mv.visitInsn(DUP); mv.visitMethodInsn(INVOKESPECIAL, "java/util/ArrayList", "<init>", "()V"); mv.visitFieldInsn(PUTFIELD, name, "errors", "Ljava/util/List;"); mv.visitVarInsn(ALOAD, 0); mv.visitInsn(ICONST_1); mv.visitFieldInsn(PUTFIELD, name, "failOnError", "Z"); mv.visitInsn(RETURN); mv.visitMaxs(3, 3); mv.visitEnd(); } { mv = cw.visitMethod(ACC_PUBLIC, "emitErrorMessage", "(Ljava/lang/String;)V", null, null); mv.visitCode(); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, name, "errors", "Ljava/util/List;"); mv.visitVarInsn(ALOAD, 1); mv.visitMethodInsn(INVOKEINTERFACE, "java/util/List", "add", "(Ljava/lang/Object;)Z"); mv.visitInsn(POP); mv.visitInsn(RETURN); mv.visitMaxs(2, 2); mv.visitEnd(); } { mv = cw.visitMethod(ACC_PUBLIC, "getErrors", "()Ljava/util/List;", "()Ljava/util/List<Ljava/lang/String;>;", null); mv.visitCode(); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, name, "errors", "Ljava/util/List;"); mv.visitInsn(ARETURN); mv.visitMaxs(1, 1); mv.visitEnd(); } { mv = cw.visitMethod(ACC_PUBLIC, "isFailOnError", "()Z", null, null); mv.visitCode(); mv.visitVarInsn(ALOAD, 0); mv.visitFieldInsn(GETFIELD, name, "failOnError", "Z"); mv.visitInsn(IRETURN); mv.visitMaxs(1, 1); mv.visitEnd(); } { mv = cw.visitMethod(ACC_PUBLIC, "setFailOnError", "(Z)V", null, null); mv.visitCode(); mv.visitVarInsn(ALOAD, 0); mv.visitVarInsn(ILOAD, 1); mv.visitFieldInsn(PUTFIELD, name, "failOnError", "Z"); mv.visitInsn(RETURN); mv.visitMaxs(2, 2); mv.visitEnd(); } cw.visitEnd(); byte[] b = cw.toByteArray(); AunitClassloader ac = new AunitClassloader(lexerClass.getClassLoader()); return ac.defineClass(name.replace('/', '.'), b); } }