com.headius.jsr292mock.Mock Maven / Gradle / Ivy

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package com.headius.jsr292mock;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.xml.ASMContentHandler;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * This class takes an XML description of JSR292 API and creates the
 * corresponding jar.
 */
public class Mock {

    public static void main(String[] args) throws SAXException, IOException, ParserConfigurationException {
        String inputFile = args[0];
        final String outputDir = args[1];
        try (FileInputStream input = new FileInputStream(inputFile)) {
            SAXParserFactory parserFactory = SAXParserFactory.newInstance();
            parserFactory.setNamespaceAware(true);
            SAXParser parser = parserFactory.newSAXParser();
            
            parser.parse(input, new DefaultHandler() {
                private String className;
                private ClassWriter writer;
                private ASMContentHandler asmContentHandler;

                @Override
                public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
                    if (localName.equals("jsr292-mock")) {
                        return; // skip it
                    }
                    if (localName.equals("class")) {
                        className = atts.getValue("", "name");
                        writer = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_MAXS);
                        ClassVisitor cv = new ClassVisitor(Opcodes.ASM5, writer) {
                            @Override
                            public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
                                MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
                                if ((access & (Opcodes.ACC_ABSTRACT | Opcodes.ACC_NATIVE)) != 0) {
                                    return mv;
                                }
                                return new MethodVisitor(Opcodes.ASM5, mv) {
                                    @Override
                                    public void visitEnd() {
                                        // add a default code
                                        super.visitCode();
                                        super.visitTypeInsn(Opcodes.NEW, "java/lang/UnsupportedOperationException");
                                        super.visitInsn(Opcodes.DUP);
                                        super.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/UnsupportedOperationException",
                                                "", "()V");
                                        super.visitInsn(Opcodes.ATHROW);

                                        super.visitMaxs(-1, -1);
                                        super.visitEnd();
                                    }
                                };
                            }
                        };
                        asmContentHandler = new ASMContentHandler(cv);
                    }
                    asmContentHandler.startElement(uri, localName, qName, atts);
                }

                @Override
                public void endElement(String uri, String localName, String qName) throws SAXException {
                    if (localName.equals("jsr292-mock")) {
                        return; // skip it
                    }
                    asmContentHandler.endElement(uri, localName, qName);
                    if (localName.equals("class")) {
                        new File(outputDir, className).getParentFile().mkdirs();
                        try (FileOutputStream classOut = new FileOutputStream(new File(outputDir, className + ".class"))) {
                            classOut.write(writer.toByteArray());
                        } catch (IOException e) {
                            throw (SAXException) new SAXException(e.getLocalizedMessage()).initCause(e);
                        }

                        className = null;
                        writer = null;
                        asmContentHandler = null;
                    }
                }
            });
        }
    }
}