org.ow2.asm/asm-tree/4.2 : org/objectweb/asm/xml/Processor.java

Processor
http://asm.objectweb.org/asm-tree/: A very small and fast Java bytecode manipulation framework (ObjectWeb)
Eric Bruneton
Eugene Kuleshov
Remi Forax
ASM XML Adapter
Copyright (c) 2004-2011, Eugene Kuleshov
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. Neither the name of the copyright holders nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.
/***
 * ASM XML Adapter
 * Copyright (c) 2004-2011, Eugene Kuleshov
 * 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. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.objectweb.asm.xml;

import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

import javax.xml.transform.Source;
import javax.xml.transform.Templates;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamSource;

import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.helpers.AttributesImpl;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.helpers.XMLReaderFactory;

Processor is a command line tool that can be used for bytecode waving
directed by XSL transformation.

In order to use a concrete XSLT engine, system property
javax.xml.transform.TransformerFactory must be set to one of the
following values.



jd.xslt
jd.xml.xslt.trax.TransformerFactoryImpl


Saxon
net.sf.saxon.TransformerFactoryImpl


Caucho
com.caucho.xsl.Xsl


Xalan interpeter
org.apache.xalan.processor.TransformerFactory


Xalan xsltc
org.apache.xalan.xsltc.trax.TransformerFactoryImpl



Author: Eugene Kuleshov/**
 * Processor is a command line tool that can be used for bytecode waving
 * directed by XSL transformation.
 * <p>
 * In order to use a concrete XSLT engine, system property
 * <tt>javax.xml.transform.TransformerFactory</tt> must be set to one of the
 * following values.
 * 
 * <blockquote>
 * <table border="1" cellspacing="0" cellpadding="3">
 * <tr>
 * <td>jd.xslt</td>
 * <td>jd.xml.xslt.trax.TransformerFactoryImpl</td>
 * </tr>
 * 
 * <tr>
 * <td>Saxon</td>
 * <td>net.sf.saxon.TransformerFactoryImpl</td>
 * </tr>
 * 
 * <tr>
 * <td>Caucho</td>
 * <td>com.caucho.xsl.Xsl</td>
 * </tr>
 * 
 * <tr>
 * <td>Xalan interpeter</td>
 * <td>org.apache.xalan.processor.TransformerFactory</td>
 * </tr>
 * 
 * <tr>
 * <td>Xalan xsltc</td>
 * <td>org.apache.xalan.xsltc.trax.TransformerFactoryImpl</td>
 * </tr>
 * </table>
 * </blockquote>
 * 
 * @author Eugene Kuleshov
 */
public class Processor {

    public static final int BYTECODE = 1;

    public static final int MULTI_XML = 2;

    public static final int SINGLE_XML = 3;

    private static final String SINGLE_XML_NAME = "classes.xml";

    private final int inRepresentation;

    private final int outRepresentation;

    private final InputStream input;

    private final OutputStream output;

    private final Source xslt;

    private int n = 0;

    public Processor(final int inRepresenation, final int outRepresentation,
            final InputStream input, final OutputStream output,
            final Source xslt) {
        this.inRepresentation = inRepresenation;
        this.outRepresentation = outRepresentation;
        this.input = input;
        this.output = output;
        this.xslt = xslt;
    }

    public int process() throws TransformerException, IOException, SAXException {
        ZipInputStream zis = new ZipInputStream(input);
        final ZipOutputStream zos = new ZipOutputStream(output);
        final OutputStreamWriter osw = new OutputStreamWriter(zos);

        Thread.currentThread().setContextClassLoader(
                getClass().getClassLoader());

        TransformerFactory tf = TransformerFactory.newInstance();
        if (!tf.getFeature(SAXSource.FEATURE)
                || !tf.getFeature(SAXResult.FEATURE)) {
            return 0;
        }

        SAXTransformerFactory saxtf = (SAXTransformerFactory) tf;
        Templates templates = null;
        if (xslt != null) {
            templates = saxtf.newTemplates(xslt);
        }

        // configuring outHandlerFactory
        // ///////////////////////////////////////////////////////

        EntryElement entryElement = getEntryElement(zos);

        ContentHandler outDocHandler = null;
        switch (outRepresentation) {
        case BYTECODE:
            outDocHandler = new OutputSlicingHandler(
                    new ASMContentHandlerFactory(zos), entryElement, false);
            break;

        case MULTI_XML:
            outDocHandler = new OutputSlicingHandler(new SAXWriterFactory(osw,
                    true), entryElement, true);
            break;

        case SINGLE_XML:
            ZipEntry outputEntry = new ZipEntry(SINGLE_XML_NAME);
            zos.putNextEntry(outputEntry);
            outDocHandler = new SAXWriter(osw, false);
            break;

        }

        // configuring inputDocHandlerFactory
        // /////////////////////////////////////////////////
        ContentHandler inDocHandler;
        if (templates == null) {
            inDocHandler = outDocHandler;
        } else {
            inDocHandler = new InputSlicingHandler("class", outDocHandler,
                    new TransformerHandlerFactory(saxtf, templates,
                            outDocHandler));
        }
        ContentHandlerFactory inDocHandlerFactory = new SubdocumentHandlerFactory(
                inDocHandler);

        if (inDocHandler != null && inRepresentation != SINGLE_XML) {
            inDocHandler.startDocument();
            inDocHandler.startElement("", "classes", "classes",
                    new AttributesImpl());
        }

        int i = 0;
        ZipEntry ze;
        while ((ze = zis.getNextEntry()) != null) {
            update(ze.getName(), n++);
            if (isClassEntry(ze)) {
                processEntry(zis, ze, inDocHandlerFactory);
            } else {
                OutputStream os = entryElement.openEntry(getName(ze));
                copyEntry(zis, os);
                entryElement.closeEntry();
            }

            i++;
        }

        if (inDocHandler != null && inRepresentation != SINGLE_XML) {
            inDocHandler.endElement("", "classes", "classes");
            inDocHandler.endDocument();
        }

        if (outRepresentation == SINGLE_XML) {
            zos.closeEntry();
        }
        zos.flush();
        zos.close();

        return i;
    }

    private void copyEntry(final InputStream is, final OutputStream os)
            throws IOException {
        if (outRepresentation == SINGLE_XML) {
            return;
        }

        byte[] buff = new byte[2048];
        int i;
        while ((i = is.read(buff)) != -1) {
            os.write(buff, 0, i);
        }
    }

    private boolean isClassEntry(final ZipEntry ze) {
        String name = ze.getName();
        return inRepresentation == SINGLE_XML && name.equals(SINGLE_XML_NAME)
                || name.endsWith(".class") || name.endsWith(".class.xml");
    }

    private void processEntry(final ZipInputStream zis, final ZipEntry ze,
            final ContentHandlerFactory handlerFactory) {
        ContentHandler handler = handlerFactory.createContentHandler();
        try {

            // if (CODE2ASM.equals(command)) { // read bytecode and process it
            // // with TraceClassVisitor
            // ClassReader cr = new ClassReader(readEntry(zis, ze));
            // cr.accept(new TraceClassVisitor(null, new PrintWriter(os)),
            // false);
            // }

            boolean singleInputDocument = inRepresentation == SINGLE_XML;
            if (inRepresentation == BYTECODE) { // read bytecode and process it
                // with handler
                ClassReader cr = new ClassReader(readEntry(zis, ze));
                cr.accept(new SAXClassAdapter(handler, singleInputDocument), 0);

            } else { // read XML and process it with handler
                XMLReader reader = XMLReaderFactory.createXMLReader();
                reader.setContentHandler(handler);
                reader.parse(new InputSource(
                        singleInputDocument ? (InputStream) new ProtectedInputStream(
                                zis) : new ByteArrayInputStream(readEntry(zis,
                                ze))));

            }
        } catch (Exception ex) {
            update(ze.getName(), 0);
            update(ex, 0);
        }
    }

    private EntryElement getEntryElement(final ZipOutputStream zos) {
        if (outRepresentation == SINGLE_XML) {
            return new SingleDocElement(zos);
        }
        return new ZipEntryElement(zos);
    }

    // private ContentHandlerFactory getHandlerFactory(
    // OutputStream os,
    // SAXTransformerFactory saxtf,
    // Templates templates)
    // {
    // ContentHandlerFactory factory = null;
    // if (templates == null) {
    // if (outputRepresentation == BYTECODE) { // factory used to write
    // // bytecode
    // factory = new ASMContentHandlerFactory(os, computeMax);
    // } else { // factory used to write XML
    // factory = new SAXWriterFactory(os, true);
    // }
    // } else {
    // if (outputRepresentation == BYTECODE) { // factory used to transform
    // // and then write bytecode
    // factory = new ASMTransformerHandlerFactory(saxtf,
    // templates,
    // os,
    // computeMax);
    // } else { // factory used to transformand then write XML
    // factory = new TransformerHandlerFactory(saxtf,
    // templates,
    // os,
    // outputRepresentation == SINGLE_XML);
    // }
    // }
    // return factory;
    // }

    private String getName(final ZipEntry ze) {
        String name = ze.getName();
        if (isClassEntry(ze)) {
            if (inRepresentation != BYTECODE && outRepresentation == BYTECODE) {
                name = name.substring(0, name.length() - 4); // .class.xml to
                // .class
            } else if (inRepresentation == BYTECODE
                    && outRepresentation != BYTECODE) {
                name += ".xml"; // .class to .class.xml
            }
            // } else if( CODE2ASM.equals( command)) {
            // name = name.substring( 0, name.length()-6).concat( ".asm");
        }
        return name;
    }

    private static byte[] readEntry(final InputStream zis, final ZipEntry ze)
            throws IOException {
        long size = ze.getSize();
        if (size > -1) {
            byte[] buff = new byte[(int) size];
            int k = 0;
            int n;
            while ((n = zis.read(buff, k, buff.length - k)) > 0) {
                k += n;
            }
            return buff;
        }

        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        byte[] buff = new byte[4096];
        int i;
        while ((i = zis.read(buff)) != -1) {
            bos.write(buff, 0, i);
        }
        return bos.toByteArray();
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.util.Observer#update(java.util.Observable, java.lang.Object)
     */
    protected void update(final Object arg, final int n) {
        if (arg instanceof Throwable) {
            ((Throwable) arg).printStackTrace();
        } else {
            if (n % 100 == 0) {
                System.err.println(n + " " + arg);
            }
        }
    }

    public static void main(final String[] args) throws Exception {
        if (args.length < 2) {
            showUsage();
            return;
        }

        int inRepresentation = getRepresentation(args[0]);
        int outRepresentation = getRepresentation(args[1]);

        InputStream is = System.in;
        OutputStream os = new BufferedOutputStream(System.out);

        Source xslt = null;
        // boolean computeMax = true;

        for (int i = 2; i < args.length; i++) {
            if ("-in".equals(args[i])) {
                is = new FileInputStream(args[++i]);

            } else if ("-out".equals(args[i])) {
                os = new BufferedOutputStream(new FileOutputStream(args[++i]));

            } else if ("-xslt".equals(args[i])) {
                xslt = new StreamSource(new FileInputStream(args[++i]));

                // } else if( "-computemax".equals( args[ i].toLowerCase())) {
                // computeMax = true;

            } else {
                showUsage();
                return;

            }
        }

        if (inRepresentation == 0 || outRepresentation == 0) {
            showUsage();
            return;
        }

        Processor m = new Processor(inRepresentation, outRepresentation, is,
                os, xslt);

        long l1 = System.currentTimeMillis();
        int n = m.process();
        long l2 = System.currentTimeMillis();
        System.err.println(n);
        System.err.println((l2 - l1) + "ms  " + 1000f * n / (l2 - l1)
                + " resources/sec");
    }

    private static int getRepresentation(final String s) {
        if ("code".equals(s)) {
            return BYTECODE;
        } else if ("xml".equals(s)) {
            return MULTI_XML;
        } else if ("singlexml".equals(s)) {
            return SINGLE_XML;
        }
        return 0;
    }

    private static void showUsage() {
        System.err
                .println("Usage: Main <in format> <out format> [-in <input jar>] [-out <output jar>] [-xslt <xslt fiel>]");
        System.err
                .println("  when -in or -out is omitted sysin and sysout would be used");
        System.err
                .println("  <in format> and <out format> - code | xml | singlexml");
    }

    IputStream wrapper class used to protect input streams from being closed
by some stupid XML parsers.
/**
     * IputStream wrapper class used to protect input streams from being closed
     * by some stupid XML parsers.
     */
    private static final class ProtectedInputStream extends InputStream {
        private final InputStream is;

        ProtectedInputStream(final InputStream is) {
            this.is = is;
        }

        @Override
        public final void close() throws IOException {
        }

        @Override
        public final int read() throws IOException {
            return is.read();
        }

        @Override
        public final int read(final byte[] b, final int off, final int len)
                throws IOException {
            return is.read(b, off, len);
        }

        @Override
        public final int available() throws IOException {
            return is.available();
        }
    }

    A ContentHandlerFactory is used to create ContentHandler instances for concrete context. /**
     * A {@link ContentHandlerFactory ContentHandlerFactory} is used to create
     * {@link org.xml.sax.ContentHandler ContentHandler} instances for concrete
     * context.
     */
    private static interface ContentHandlerFactory {

        Creates an instance of the content handler.
Returns: content handler/**
         * Creates an instance of the content handler.
         * 
         * @return content handler
         */
        ContentHandler createContentHandler();

    }

    SAXWriterFactory
/**
     * SAXWriterFactory
     */
    private static final class SAXWriterFactory implements
            ContentHandlerFactory {
        private final Writer w;

        private final boolean optimizeEmptyElements;

        SAXWriterFactory(final Writer w, final boolean optimizeEmptyElements) {
            this.w = w;
            this.optimizeEmptyElements = optimizeEmptyElements;
        }

        public final ContentHandler createContentHandler() {
            return new SAXWriter(w, optimizeEmptyElements);
        }

    }

    ASMContentHandlerFactory
/**
     * ASMContentHandlerFactory
     */
    private static final class ASMContentHandlerFactory implements
            ContentHandlerFactory {
        final OutputStream os;

        ASMContentHandlerFactory(final OutputStream os) {
            this.os = os;
        }

        public final ContentHandler createContentHandler() {
            final ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
            return new ASMContentHandler(cw) {
                @Override
                public void endDocument() throws SAXException {
                    try {
                        os.write(cw.toByteArray());
                    } catch (IOException e) {
                        throw new SAXException(e);
                    }
                }
            };
        }

    }

    TransformerHandlerFactory
/**
     * TransformerHandlerFactory
     */
    private static final class TransformerHandlerFactory implements
            ContentHandlerFactory {
        private SAXTransformerFactory saxtf;

        private final Templates templates;

        private ContentHandler outputHandler;

        TransformerHandlerFactory(final SAXTransformerFactory saxtf,
                final Templates templates, final ContentHandler outputHandler) {
            this.saxtf = saxtf;
            this.templates = templates;
            this.outputHandler = outputHandler;
        }

        public final ContentHandler createContentHandler() {
            try {
                TransformerHandler handler = saxtf
                        .newTransformerHandler(templates);
                handler.setResult(new SAXResult(outputHandler));
                return handler;
            } catch (TransformerConfigurationException ex) {
                throw new RuntimeException(ex.toString());
            }
        }
    }

    SubdocumentHandlerFactory
/**
     * SubdocumentHandlerFactory
     */
    private static final class SubdocumentHandlerFactory implements
            ContentHandlerFactory {
        private final ContentHandler subdocumentHandler;

        SubdocumentHandlerFactory(final ContentHandler subdocumentHandler) {
            this.subdocumentHandler = subdocumentHandler;
        }

        public final ContentHandler createContentHandler() {
            return subdocumentHandler;
        }

    }

    A ContentHandler and LexicalHandler that serializes XML from SAX 2.0 events into Writer.  This implementation does not support namespaces, entity
definitions (uncluding DTD), CDATA and text elements. 
/**
     * A {@link org.xml.sax.ContentHandler ContentHandler} and
     * {@link org.xml.sax.ext.LexicalHandler LexicalHandler} that serializes XML
     * from SAX 2.0 events into {@link java.io.Writer Writer}.
     * 
     * <i><blockquote> This implementation does not support namespaces, entity
     * definitions (uncluding DTD), CDATA and text elements. </blockquote></i>
     */
    private static final class SAXWriter extends DefaultHandler implements
            LexicalHandler {
        private static final char[] OFF = "                                                                                                        "
                .toCharArray();

        private Writer w;

        private final boolean optimizeEmptyElements;

        private boolean openElement = false;

        private int ident = 0;

        Creates SAXWriter.
Params: w – 
           writer
optimizeEmptyElements – 
           if set to true, short XML syntax will be used
           for empty elements/**
         * Creates <code>SAXWriter</code>.
         * 
         * @param w
         *            writer
         * @param optimizeEmptyElements
         *            if set to <code>true</code>, short XML syntax will be used
         *            for empty elements
         */
        SAXWriter(final Writer w, final boolean optimizeEmptyElements) {
            this.w = w;
            this.optimizeEmptyElements = optimizeEmptyElements;
        }

        @Override
        public final void startElement(final String ns, final String localName,
                final String qName, final Attributes atts) throws SAXException {
            try {
                closeElement();

                writeIdent();
                w.write('<' + qName);
                if (atts != null && atts.getLength() > 0) {
                    writeAttributes(atts);
                }

                if (optimizeEmptyElements) {
                    openElement = true;
                } else {
                    w.write(">\n");
                }
                ident += 2;

            } catch (IOException ex) {
                throw new SAXException(ex);

            }
        }

        @Override
        public final void endElement(final String ns, final String localName,
                final String qName) throws SAXException {
            ident -= 2;
            try {
                if (openElement) {
                    w.write("/>\n");
                    openElement = false;
                } else {
                    writeIdent();
                    w.write("</" + qName + ">\n");
                }

            } catch (IOException ex) {
                throw new SAXException(ex);

            }
        }

        @Override
        public final void endDocument() throws SAXException {
            try {
                w.flush();

            } catch (IOException ex) {
                throw new SAXException(ex);

            }
        }

        public final void comment(final char[] ch, final int off, final int len)
                throws SAXException {
            try {
                closeElement();

                writeIdent();
                w.write("<!-- ");
                w.write(ch, off, len);
                w.write(" -->\n");

            } catch (IOException ex) {
                throw new SAXException(ex);

            }
        }

        public final void startDTD(final String arg0, final String arg1,
                final String arg2) throws SAXException {
        }

        public final void endDTD() throws SAXException {
        }

        public final void startEntity(final String arg0) throws SAXException {
        }

        public final void endEntity(final String arg0) throws SAXException {
        }

        public final void startCDATA() throws SAXException {
        }

        public final void endCDATA() throws SAXException {
        }

        private final void writeAttributes(final Attributes atts)
                throws IOException {
            StringBuffer sb = new StringBuffer();
            int len = atts.getLength();
            for (int i = 0; i < len; i++) {
                sb.append(' ').append(atts.getLocalName(i)).append("=\"")
                        .append(esc(atts.getValue(i))).append('\"');
            }
            w.write(sb.toString());
        }

        Encode string with escaping.
Params: str – 
           string to encode.
Returns: encoded string/**
         * Encode string with escaping.
         * 
         * @param str
         *            string to encode.
         * @return encoded string
         */
        private static final String esc(final String str) {
            StringBuffer sb = new StringBuffer(str.length());
            for (int i = 0; i < str.length(); i++) {
                char ch = str.charAt(i);
                switch (ch) {
                case '&':
                    sb.append("&amp;");
                    break;

                case '<':
                    sb.append("&lt;");
                    break;

                case '>':
                    sb.append("&gt;");
                    break;

                case '\"':
                    sb.append("&quot;");
                    break;

                default:
                    if (ch > 0x7f) {
                        sb.append("&#").append(Integer.toString(ch))
                                .append(';');
                    } else {
                        sb.append(ch);
                    }

                }
            }
            return sb.toString();
        }

        private final void writeIdent() throws IOException {
            int n = ident;
            while (n > 0) {
                if (n > OFF.length) {
                    w.write(OFF);
                    n -= OFF.length;
                } else {
                    w.write(OFF, 0, n);
                    n = 0;
                }
            }
        }

        private final void closeElement() throws IOException {
            if (openElement) {
                w.write(">\n");
            }
            openElement = false;
        }

    }

    A ContentHandler that splits XML documents into smaller chunks. Each chunk is processed by the nested ContentHandler obtained from ContentHandlerFactory. This is useful for running XSLT engine against large XML document that will hardly fit into the memory all together. 
TODO use complete path for subdocumentRoot
/**
     * A {@link org.xml.sax.ContentHandler ContentHandler} that splits XML
     * documents into smaller chunks. Each chunk is processed by the nested
     * {@link org.xml.sax.ContentHandler ContentHandler} obtained from
     * {@link java.net.ContentHandlerFactory ContentHandlerFactory}. This is
     * useful for running XSLT engine against large XML document that will
     * hardly fit into the memory all together.
     * <p>
     * TODO use complete path for subdocumentRoot
     */
    private static final class InputSlicingHandler extends DefaultHandler {
        private String subdocumentRoot;

        private final ContentHandler rootHandler;

        private ContentHandlerFactory subdocumentHandlerFactory;

        private boolean subdocument = false;

        private ContentHandler subdocumentHandler;

        Constructs a new SubdocumentHandler object. 
Params: subdocumentRoot – 
           name/path to the root element of the subdocument
rootHandler – 
           content handler for the entire document (subdocument
           envelope).
subdocumentHandlerFactory –  a ContentHandlerFactory used to create ContentHandler instances for subdocuments./**
         * Constructs a new {@link InputSlicingHandler SubdocumentHandler}
         * object.
         * 
         * @param subdocumentRoot
         *            name/path to the root element of the subdocument
         * @param rootHandler
         *            content handler for the entire document (subdocument
         *            envelope).
         * @param subdocumentHandlerFactory
         *            a {@link ContentHandlerFactory ContentHandlerFactory} used
         *            to create {@link ContentHandler ContentHandler} instances
         *            for subdocuments.
         */
        InputSlicingHandler(final String subdocumentRoot,
                final ContentHandler rootHandler,
                final ContentHandlerFactory subdocumentHandlerFactory) {
            this.subdocumentRoot = subdocumentRoot;
            this.rootHandler = rootHandler;
            this.subdocumentHandlerFactory = subdocumentHandlerFactory;
        }

        @Override
        public final void startElement(final String namespaceURI,
                final String localName, final String qName,
                final Attributes list) throws SAXException {
            if (subdocument) {
                subdocumentHandler.startElement(namespaceURI, localName, qName,
                        list);
            } else if (localName.equals(subdocumentRoot)) {
                subdocumentHandler = subdocumentHandlerFactory
                        .createContentHandler();
                subdocumentHandler.startDocument();
                subdocumentHandler.startElement(namespaceURI, localName, qName,
                        list);
                subdocument = true;
            } else if (rootHandler != null) {
                rootHandler.startElement(namespaceURI, localName, qName, list);
            }
        }

        @Override
        public final void endElement(final String namespaceURI,
                final String localName, final String qName) throws SAXException {
            if (subdocument) {
                subdocumentHandler.endElement(namespaceURI, localName, qName);
                if (localName.equals(subdocumentRoot)) {
                    subdocumentHandler.endDocument();
                    subdocument = false;
                }
            } else if (rootHandler != null) {
                rootHandler.endElement(namespaceURI, localName, qName);
            }
        }

        @Override
        public final void startDocument() throws SAXException {
            if (rootHandler != null) {
                rootHandler.startDocument();
            }
        }

        @Override
        public final void endDocument() throws SAXException {
            if (rootHandler != null) {
                rootHandler.endDocument();

            }
        }

        @Override
        public final void characters(final char[] buff, final int offset,
                final int size) throws SAXException {
            if (subdocument) {
                subdocumentHandler.characters(buff, offset, size);
            } else if (rootHandler != null) {
                rootHandler.characters(buff, offset, size);
            }
        }

    }

    A ContentHandler that splits XML documents into smaller chunks. Each chunk is processed by the nested ContentHandler obtained from ContentHandlerFactory. This is useful for running XSLT engine against large XML document that will hardly fit into the memory all together. 
TODO use complete path for subdocumentRoot
/**
     * A {@link org.xml.sax.ContentHandler ContentHandler} that splits XML
     * documents into smaller chunks. Each chunk is processed by the nested
     * {@link org.xml.sax.ContentHandler ContentHandler} obtained from
     * {@link java.net.ContentHandlerFactory ContentHandlerFactory}. This is
     * useful for running XSLT engine against large XML document that will
     * hardly fit into the memory all together.
     * 
     * <p>
     * TODO use complete path for subdocumentRoot
     */
    private static final class OutputSlicingHandler extends DefaultHandler {
        private final String subdocumentRoot;

        private ContentHandlerFactory subdocumentHandlerFactory;

        private final EntryElement entryElement;

        private boolean isXml;

        private boolean subdocument = false;

        private ContentHandler subdocumentHandler;

        Constructs a new SubdocumentHandler object. 
Params: subdocumentHandlerFactory –  a ContentHandlerFactory used to create ContentHandler instances for subdocuments.
entryElement – 
           TODO.
isXml – 
           TODO./**
         * Constructs a new {@link OutputSlicingHandler SubdocumentHandler}
         * object.
         * 
         * @param subdocumentHandlerFactory
         *            a {@link ContentHandlerFactory ContentHandlerFactory} used
         *            to create {@link ContentHandler ContentHandler} instances
         *            for subdocuments.
         * @param entryElement
         *            TODO.
         * @param isXml
         *            TODO.
         */
        OutputSlicingHandler(
                final ContentHandlerFactory subdocumentHandlerFactory,
                final EntryElement entryElement, final boolean isXml) {
            this.subdocumentRoot = "class";
            this.subdocumentHandlerFactory = subdocumentHandlerFactory;
            this.entryElement = entryElement;
            this.isXml = isXml;
        }

        @Override
        public final void startElement(final String namespaceURI,
                final String localName, final String qName,
                final Attributes list) throws SAXException {
            if (subdocument) {
                subdocumentHandler.startElement(namespaceURI, localName, qName,
                        list);
            } else if (localName.equals(subdocumentRoot)) {
                String name = list.getValue("name");
                if (name == null || name.length() == 0) {
                    throw new SAXException(
                            "Class element without name attribute.");
                }
                try {
                    entryElement.openEntry(isXml ? name + ".class.xml" : name
                            + ".class");
                } catch (IOException ex) {
                    throw new SAXException(ex.toString(), ex);
                }
                subdocumentHandler = subdocumentHandlerFactory
                        .createContentHandler();
                subdocumentHandler.startDocument();
                subdocumentHandler.startElement(namespaceURI, localName, qName,
                        list);
                subdocument = true;
            }
        }

        @Override
        public final void endElement(final String namespaceURI,
                final String localName, final String qName) throws SAXException {
            if (subdocument) {
                subdocumentHandler.endElement(namespaceURI, localName, qName);
                if (localName.equals(subdocumentRoot)) {
                    subdocumentHandler.endDocument();
                    subdocument = false;
                    try {
                        entryElement.closeEntry();
                    } catch (IOException ex) {
                        throw new SAXException(ex.toString(), ex);
                    }
                }
            }
        }

        @Override
        public final void startDocument() throws SAXException {
        }

        @Override
        public final void endDocument() throws SAXException {
        }

        @Override
        public final void characters(final char[] buff, final int offset,
                final int size) throws SAXException {
            if (subdocument) {
                subdocumentHandler.characters(buff, offset, size);
            }
        }

    }

    private static interface EntryElement {

        OutputStream openEntry(String name) throws IOException;

        void closeEntry() throws IOException;

    }

    private static final class SingleDocElement implements EntryElement {
        private final OutputStream os;

        SingleDocElement(final OutputStream os) {
            this.os = os;
        }

        public OutputStream openEntry(final String name) throws IOException {
            return os;
        }

        public void closeEntry() throws IOException {
            os.flush();
        }

    }

    private static final class ZipEntryElement implements EntryElement {
        private ZipOutputStream zos;

        ZipEntryElement(final ZipOutputStream zos) {
            this.zos = zos;
        }

        public OutputStream openEntry(final String name) throws IOException {
            ZipEntry entry = new ZipEntry(name);
            zos.putNextEntry(entry);
            return zos;
        }

        public void closeEntry() throws IOException {
            zos.flush();
            zos.closeEntry();
        }

    }

}
jd.xslt	jd.xml.xslt.trax.TransformerFactoryImpl
Saxon	net.sf.saxon.TransformerFactoryImpl
Caucho	com.caucho.xsl.Xsl
Xalan interpeter	org.apache.xalan.processor.TransformerFactory
Xalan xsltc	org.apache.xalan.xsltc.trax.TransformerFactoryImpl
/

org.ow2.asm/ asm-tree/ 4.2/ org/objectweb/asm/xml/Processor.java
