DataEncoder


1   /* ****************************************************************************
2    * DataEncoder.java
3    *
4    * Compile XML directly to SWF bytecodes.
5    * ****************************************************************************/
6   
7   /* J_LZ_COPYRIGHT_BEGIN *******************************************************
8   * Copyright 2001-2004 Laszlo Systems, Inc.  All Rights Reserved.              *
9   * Use is subject to license terms.                                            *
10  * J_LZ_COPYRIGHT_END *********************************************************/
11  
12  package org.openlaszlo.xml;
13  
14  import java.io.*;
15  import java.util.*;
16  
17  import org.xml.sax.*;
18  
19  import org.openlaszlo.xml.internal.*;
20  import org.openlaszlo.iv.flash.util.*;
21  import org.openlaszlo.iv.flash.api.action.*;
22  import org.openlaszlo.iv.flash.api.*;
23  import org.openlaszlo.compiler.CompilationError;
24  import org.openlaszlo.utils.ChainedException;
25  import org.openlaszlo.utils.FileUtils;
26  import org.openlaszlo.utils.HashIntTable;
27  
28  import org.jdom.input.SAXBuilder;
29  import org.jdom.output.SAXOutputter;
30  import org.jdom.JDOMException;
31  import org.jdom.Document;
32  import org.jdom.Attribute;
33  import org.jdom.Element;
34  import org.xml.sax.Attributes  ;
35  import org.xml.sax.helpers.AttributesImpl  ;
36  
37  import org.apache.log4j.*;
38  
39  
40  /**
41   * API to compile XML-like data sets to SWF bytecode format.
42   *<p>
43   * This class implements the SAX ContentHandler API, and could possibly be used
44   * directly with a SAX Parser, but is designed to be used manually as shown below.
45   * <p>
46   * Example usage:
47   * <pre>
48   * import org.xml.sax.helpers.AttributesImpl;
49   * 
50   *    // send simple row data as node with attributes
51   *    InputStream getDataInputStream(Request req, Response resp) {
52   *        Connection conn = DriverManager.getConnection(ConnectionPoolManager.URL_PREFIX + alias, null, null);
53   *        Statement stmt = conn.createStatement();
54   *        ResultSet resultset = stmt.executeQuery("SELECT NAME, AGE, ID FROM EMPLOYEES");
55   *        AttributesImpl emptyAttr = new AttributesImpl();
56   * 
57   * 
58   *        DataEncoder db = new DataEncoder();
59   *        db.startDocument();
60   *        db.startElement("results", emptyAttr);
61   * 
62   *        while (resultset.next()) {
63   *            AttributesImpl attrs = new AttributesImpl();
64   *            //Output the values as attributes
65   *            attrs.addAttribute("", "name", "", "CDATA", resultset.getString("name"));
66   *            attrs.addAttribute("", "age", "", "CDATA", resultset.getString("age"));
67   *            attrs.addAttribute("", "id", "", "CDATA", resultset.getString("id"));
68   *            db.startElement("row", attrs);
69   *            db.endElement();
70   *        }
71   *        db.endElement();
72   *        db.endDocument();
73   * 
74   *        OutputStream out = resp.getOutputStream();
75   *        return db.getInputStream();
76   *    }
77   * </pre>
78   */
79  public class DataEncoder implements org.xml.sax.ContentHandler   {
80  
81      /* Logger */
82      private static Logger mLogger  = Logger.getLogger(DataEncoder.class);
83  
84      /** Hint to allocate buffer size large enough to hold output. */
85      private int initsize = 0;
86      private static final int DEFAULT_BUFFER_SIZE = 4096;
87  
88      /** 
89       * The SWF file
90       */
91      private FlashOutput mSWF = null;
92      /**
93       * Size of the SWF file.
94       */
95      private long mSize = -1;
96  
97      // Target version of Flash to compile to
98      int mFlashVersion = 6;
99  
100     /**
101      * Constructs an empty DataEncoder.
102      */
103     public DataEncoder () { }
104 
105     /**
106      * Constructs a DataEncoder with a buffer allocation size hint.
107      * @param initsize hint to allocate buffer size large enough to hold output.
108      */
109     public DataEncoder (int initsize) {
110         this.initsize = initsize;
111     }
112 
113     //============================================================
114     // SAX API
115     //============================================================
116 
117     /**
118      * Receive notification of character data.
119      *
120      * @param ch the characters from the XML document.
121      * @param start the start position in the array.
122      * @param length the number of characters to read from the array.
123      *
124      * @see #characters(String) characters(String)
125      */
126     public void characters(char[] ch, int start, int length) {
127         String   text = new String  (ch, start, length);
128         characters(text);
129     }
130 
131     /**
132      * Receive notification of string data.
133      *
134      * @param text the string from the XML document.
135      *
136      * @see #characters(char[], int, int) characters(char[], int, int)
137      */
138     public void characters(String   text) {
139         // makeTextNode = function (text, parent)
140         // dup pointer to parent (who is at top of stack)
141         // DUP
142         body.writeByte(Actions.PushDuplicate);
143         // Push text
144 
145 
146         body.writeByte(Actions.PushData);
147         // Leave a two byte space for the PUSH length
148         // Mark where we are, so we can rewrite this with correct length later.
149         int push_bufferpos = body.getPos();
150         body.writeWord(0); // placeholder 16-bit length field 
151 
152         DataCommon.pushMergedStringData(text, body, dc);
153         // Set up argsnum and function name
154         // PUSH 2, _tdn
155         body.writeByte(0x07); // INT type
156         body.writeDWord(2);   // '2' integer constant ; number of args to function
157         body.writeByte(0x08);     //  SHORT DICTIONARY LOOKUP
158         body.writeByte(textnode_idx);  // push function name: index of "_t" string constant
159 
160         // Now go back and fix up the size arg to the PUSH instruction
161         int total_size = body.getPos() - (push_bufferpos + 2);
162         //System.out.println("pos="+body.getPos()+ " total_size = "+total_size+"  push_bufferpos="+push_bufferpos+" nattrs="+nattrs);
163         body.writeWordAt(total_size, push_bufferpos);
164 
165         body.writeByte(Actions.CallFunction);
166         // Pop the node, because there will be no end tag for it, and it has no children.
167         body.writeByte(Actions.Pop); 
168     }
169 
170 
171     /**
172      * Receive notification of the end of an element. This method is equivalent
173      * to calling {@link #endElement() endElement()} -- the input parameters are
174      * ignored.
175      *
176      * @param uri the Namespace URI, or the empty string if the element has no
177      * Namespace URI or if Namespace processing is not being performed.
178      * @param localName the local name (without prefix), or the empty string if
179      * Namespace processing is not being performed.
180      * @param qName the qualified XML 1.0 name (with prefix), or the empty
181      * string if qualified names are not available.
182      * @see #endElement() endElement()
183      */
184     public void endElement(java.lang.String   uri, java.lang.String   localName, java.lang.String   qName) {
185         // Pop the node off the stack. 
186         body.writeByte(Actions.Pop);
187     }
188 
189     /**
190      * Receive notification of the end of an element.
191      *
192      * @see #endElement(String,String,String) endElement(String,String,String)
193      */
194     public void endElement() {
195         // Pop the node off the stack. 
196         body.writeByte(Actions.Pop);
197     }
198 
199 
200     /**
201      * End the scope of a prefix-URI mapping. This method is unimplemented.
202      *
203      * @param prefix the prefix that was being mapped.
204      */
205     public void endPrefixMapping(java.lang.String   prefix) {
206     }
207 
208     /**
209      * Receive notification of ignorable whitespace in element content. This
210      * method is unimplemented.
211      *
212      * @param ch the characters from the XML document.
213      * @param start the start position in the array.
214      * @param length the number of characters to read from the array.
215      */
216     public void ignorableWhitespace(char[] ch, int start, int length) {
217     }
218 
219     /**
220      * Receive notification of a processing instruction. This method is
221      * unimplemented.
222      *
223      * @param target the processing instruction target.
224      * @param data the processing instruction data, or null if none was
225      * supplied. The data does not include any whitespace separating it from the
226      * target.
227      */
228     public void processingInstruction(java.lang.String   target, java.lang.String   data) {
229     }
230 
231     /**
232      * Receive an object for locating the origin of SAX document events. This
233      * method is unimplemented.
234      *
235      * @param locator an object that can return the location of any SAX document
236      * event.
237      */
238     public void setDocumentLocator(Locator locator) {
239     }
240 
241     /**
242      * Receive notification of a skipped entity. This method is unimplemented.
243      *
244      * @param name the name of the skipped entity. If it is a parameter entity,
245      * the name will begin with '%', and if it is the external DTD subset, it
246      * will be the string "[dtd]".
247      */
248     public void skippedEntity(java.lang.String   name) {
249     }
250 
251     /** State vars */
252     DataContext dc;
253     // The node constructor function name. 
254     private byte constructor_idx;
255     private byte textnode_idx;
256 
257     FlashBuffer body;
258     Program program;
259     Program resultProgram;
260     FlashBuffer out;
261 
262     /**
263      * Receive notification of the beginning of a document.
264      *
265      * @see #endDocument() endDocument()
266      */
267     public void startDocument() {
268         dc = new DataContext(mFlashVersion);
269         if (mFlashVersion == 5) {
270             dc.setEncoding("Cp1252");
271         } else {
272             dc.setEncoding("UTF-8");
273         }
274         constructor_idx   = (byte) (DataCommon.addStringConstant(DataCommon.NODE_INSTANTIATOR_FN, dc) & 0xFF);
275         textnode_idx      = (byte) (DataCommon.addStringConstant(DataCommon.TEXT_INSTANTIATOR_FN, dc) & 0xFF);
276 
277         // Room at the end of the buffer for maybe some callback code to the runtime to say we're done.
278         // Allocate enough room to hold the data nodes and strings ; it should be < input XML filesize
279         body = new FlashBuffer(initsize == 0 ? DEFAULT_BUFFER_SIZE : initsize);
280         program =  new Program(body);
281 
282         // Bind the node creation functions to some short local names:
283         //  element nodes: _root._m => _m
284         program.push(new Object  []{"_m", "_root"});
285         program.getVar();
286         program.push("_m");
287         body.writeByte(Actions.GetMember);
288         program.setVar();
289 
290         //  text nodes: _root._t => _t
291         program.push(new Object  []{"_t", "_root"});
292         program.getVar();
293         program.push("_t");
294         body.writeByte(Actions.GetMember);
295         program.setVar();
296 
297         // Build a root node by calling the runtime's root node instantiator
298         // 
299         // The root node will have $n = 0, and whatever other initial conditions are needed.
300         program.push(0); // Root node creator function takes no args.
301         program.push("_root");
302         program.getVar();
303         program.push(DataCommon.ROOT_NODE_INSTANTIATOR_FN);
304         program.callMethod();
305         // The root node is now on the stack.
306         // Build data. Invariant is that it leaves the stack the way it found it.
307         
308         AttributesImpl   emptyAttr = new AttributesImpl  ();
309         startElement("resultset", emptyAttr);
310         startElement("body", emptyAttr);
311     }
312 
313     /**
314      * Receive notification of the end of a document.
315      *
316      * @see #startDocument() startDocument()
317      */
318     public void endDocument() {
319         
320         endElement();
321         // NOTE: [2003-07-17 bloch] This is where headers/meta-data would be inserted.
322         endElement();
323 
324         // The root node is sitting on the stack.
325         // Finalize; bind the variable "root" to the node that the lfc expects.
326         program.push(1); 
327         program.push("_root");
328         program.getVar();
329         program.push(DataCommon.ROOT_NODE_FINAL_FN);
330         program.callMethod();
331 
332         FlashBuffer body = program.body();
333 
334         // Bind "root" global to the top node
335         body.writeByte(Actions.PushDuplicate);
336         program.push("__lztmproot");
337         body.writeByte(Actions.StackSwap);
338         program.setVar();
339 
340         // Call into viewsystem
341         program.push("_parent");
342         program.getVar();
343         program.push(2); 
344         program.push("_parent"); 
345         program.getVar();
346         program.push("loader"); 
347         body.writeByte(Actions.GetMember);
348         program.push("returnData"); 
349         program.callMethod();
350         program.pop();
351 
352         // Collect the string dictionary data
353         byte pooldata[] = DataCommon.makeStringPool(dc);
354         // 'out' is the main FlashBuffer for composing the output file
355         final int MISC = 64;
356         out = new FlashBuffer(body.getSize() + pooldata.length + MISC);
357         // Write out string constant pool
358         out.writeByte( Actions.ConstantPool );
359         out.writeWord( pooldata.length + 2 ); // number of bytes in pool data + int (# strings)
360         out.writeWord( dc.cpool.size() ); // number of strings in pool
361         out.writeArray( pooldata, 0, pooldata.length); // copy the data
362         // Write out the code to build nodes
363         out.writeArray(body.getBuf(), 0, body.getSize());
364         resultProgram = new Program(out);
365     }
366 
367     /**
368      * @return the Flash program to build the data set.
369      */
370     private Program getProgram() {
371         return resultProgram;
372     }
373 
374 
375     /**
376      * Make SWF
377      *
378      * @return FlashFile containing entire SWF with header
379      */
380     private FlashFile makeSWFFile() {
381         // Create FlashFile object nd include action bytes
382         FlashFile file = FlashFile.newFlashFile();
383         Script s = new Script(1);
384         file.setMainScript(s);
385         file.setVersion(5);
386         Frame frame = s.newFrame();
387         frame.addFlashObject(new DoAction(resultProgram));
388         return file;
389     }
390 
391     /*
392     public int writeSWF(OutputStream w, boolean closeStream) 
393         throws IOException {
394         // Get inputstream and write to outputstream
395         InputStream input;
396         int i;
397         try {
398             FlashFile file = makeSWFFile();
399             input = file.generate().getInputStream();
400             i = FileUtils.send(input, w);
401             w.flush();
402         } catch (IVException ex) {
403             throw new ChainedException(ex);
404         } finally {
405             if (closeStream) {
406                 w.close();
407             }
408         }
409         return i;
410     }
411     */
412 
413 
414     /**
415      * Get the compiled data swf program byte codes.  Only call this after you
416      * have called {@link #endDocument endDocument()}.
417      *
418      * @return input stream containing the compiled SWF data program; only valid 
419      * after {@link #endDocument endDocument()} has been called.  Must not be called
420      * before {@link #endDocument endDocument()}.
421      */
422     public InputStream getInputStream() 
423         throws IOException {
424 
425         generate();
426         return mSWF.getInputStream();
427     }
428 
429     /**
430      * Return the size of the output object; only valid after endDocument
431      * {@link #endDocument endDocument()} has been called.  Must not be called
432      * before {@link #endDocument endDocument()}.
433      *
434      * @return long representing the size
435      */
436     public long getSize() 
437         throws IOException {
438 
439         generate();
440         return mSize;
441     }
442 
443     /**
444      * Generate the SWF file
445      */
446     private void generate() throws IOException {
447 
448         if (mSWF == null) {
449             try {
450                 InputStream input;
451                 FlashFile file = makeSWFFile();
452                 mSWF = file.generate();
453                 mSize = mSWF.pos;
454             } catch (IVException ex) {
455                 throw new ChainedException(ex);
456             }
457         }
458     }
459 
460     /**
461      * A lower level call than startElement(); attributes must be supplied by
462      * individual calls to addAttribute(). This method is unimplemented.
463      * @param localName the element name.
464      */
465     public void _startElement (String   localName) {
466 
467     }
468 
469     /** 
470      * A low level call to add an attribute, must be preceded by call to
471      * _startElement() for a given element. This method is unimplemented.
472      */
473     public void addAttribute (String   attrName, String   attrVal) {
474 
475     }
476 
477 
478     /**
479      * Receive notification of the beginning of an element. This method is
480      * equivalent to calling {@link #startElement(String, Attributes)
481      * startElement(String, Attributes)} -- the uri and qName parameters are
482      * ignored.
483      *
484      * @param uri the Namespace URI, or the empty string if the element has no
485      * Namespace URI or if Namespace processing is not being performed.
486      * @param localName the local name (without prefix), or the empty string if
487      * Namespace processing is not being performed.
488      * @param qName the qualified name (with prefix), or the empty string if
489      * qualified names are not available.
490      * @param atts the attributes attached to the element. If there are no
491      * attributes, it shall be an empty Attributes object.
492      *
493      * @see #startElement(String, Attributes) startElement(String, Attributes)
494      */
495     public void startElement(java.lang.String   uri, java.lang.String   localName, java.lang.String   qName, Attributes   atts) {
496         startElement(localName, atts);
497     }
498 
499 
500     /**
501      * Receive notification of the beginning of an element.
502      *
503      * @param localName the local name (without prefix), or the empty string if
504      * Namespace processing is not being performed.
505      * @param atts the attributes attached to the element. If there are no
506      * attributes, it shall be an empty Attributes object.
507      *
508      * @see #startElement(String, String, String, Attributes)
509      * startElement(String, String, String, Attributes)
510      */
511     public void startElement(java.lang.String   localName, Attributes   atts) {
512         int idx; // tmp var to hold a string pool index
513         // makeNodeNoText = function (attrs, name, parent)
514         // dup pointer to PARENT (who is at top of stack)
515         // DUP
516         body.writeByte(Actions.PushDuplicate);
517 
518         // We're really squeezing things down, so we are going to merge 
519         // the PUSH of the element name with the PUSH of the attribute key/value
520         // data and the attribute count. So the stack will look like
521         // [eltname attrname1 attrval1 attrname2 attrval2 ... ... nattrs]
522         // when we're done
523         body.writeByte(Actions.PushData);
524         // Leave a two byte space for the PUSH length
525         // Mark where we are, so we can rewrite this with correct length later.
526         int push_bufferpos = body.getPos();
527         body.writeWord(0); // placeholder 16-bit length field 
528 
529         // Push element NAME
530         String   eltname = localName;
531         DataCommon.pushMergedStringDataSymbol(eltname, body, dc);
532 
533         // Fold all the attribute key/value pairs into a single PUSH
534         // Build ATTRIBUTE object
535         int nattrs = atts.getLength();
536 
537         // PUSH := {0x96, lenlo, lenhi, 0x00, char, char, char, ...0x00, }
538         for (int i = 0; i < nattrs; i++) {
539             String   attrname = atts.getLocalName(i);
540             //System.out.print("Attr " + attrname);
541             DataCommon.pushMergedStringDataSymbol(attrname, body, dc);
542 
543             String   attrval = atts.getValue(i);
544             //System.out.println("= " + attrval);
545             DataCommon.pushMergedStringData(attrval, body, dc);
546         }
547         // create the attrs object; push the attr count
548         body.writeByte(0x07); // INT type
549         body.writeDWord(nattrs);
550         // Now go back and fix up the size arg to the PUSH instruction
551         int total_size = body.getPos() - (push_bufferpos + 2);
552         //System.out.println("pos="+body.getPos()+ " total_size = "+total_size+"  push_bufferpos="+push_bufferpos+" nattrs="+nattrs);
553         body.writeWordAt(total_size, push_bufferpos);
554         body.writeByte(Actions.InitObject);
555 
556         // stack now has [parent, name, attrs]
557         // Push # of args and node-instantiator-function name
558         // PUSH 3, _mdn
559         // [PUSHDATA, 7, 0,  0x07, 03 00 00 00 0x08, constructor_idx]
560         body.writeByte(Actions.PushData);
561         body.writeWord(7);
562         body.writeByte(0x07); // INT type
563         body.writeDWord(3);   // '3' integer constant , number of args to node constructor fn
564         body.writeByte(0x08);     //  SHORT DICTIONARY LOOKUP type
565         body.writeByte(constructor_idx);  // index of "_m" string constant
566         body.writeByte(Actions.CallFunction);
567         // We leave the new node on the stack, so we can reference it as the parent 
568         // Stack => [parentnode newnode]
569     }
570 
571     /**
572      * Begin the scope of a prefix-URI Namespace mapping. This method is
573      * unimplemented.
574      *
575      * @param prefix the Namespace prefix being declared.
576      * @param uri the Namespace URI the prefix is mapped to.
577      */
578     public void startPrefixMapping(java.lang.String   prefix, java.lang.String   uri) {
579     }
580 
581 
582     //============================================================
583     // End SAX ContentHandler Compatibility
584     //============================================================
585 
586 
587     /**
588      * Parse a DOM Document and pass it to DataEncoder via JDOM SAXOutputter
589      *
590      * @param doc DOM Document to build.
591      * @throws DataCompilerException if there was a problem compiling the Document.
592      */
593     public void buildFromDocument(Document doc) throws DataEncoderException {
594         try {
595             SAXOutputter saxout = new SAXOutputter(this);
596             saxout.output(doc);
597         }
598         catch (JDOMException e) {
599             throw new DataEncoderException("Error compiling XML from Document: "+e.getMessage());
600         }
601     }
602 
603     /**
604      * Build from a DOM Element.
605      *
606      * @param e DOM Element.
607      */
608     public void buildFromElement(Element e) {
609         startDocument();
610         traverseDOM(e);
611         endDocument();
612     }
613 
614    String   getQualifiedName(Attribute attr)
615    {
616        // AttributesImpl expects a full qualified name or the empty string, if
617        // qualified name is not available.
618 
619        if (attr.getNamespacePrefix().equals(""))
620            return "";
621        return attr.getQualifiedName();
622    }
623 
624    String   getAttributeType(Attribute attr)
625    {
626        // Not really sure if returning an "ENUMERATED" string is the right
627        // thing to pass back for enumerated types.
628 
629        int type = attr.getAttributeType();
630        if      ( type == Attribute.CDATA_ATTRIBUTE)      { return "CDATA"; }
631        else if ( type == Attribute.ID_ATTRIBUTE)         { return "ID"; }
632        else if ( type == Attribute.IDREF_ATTRIBUTE)      { return "IDREF"; }
633        else if ( type == Attribute.IDREFS_ATTRIBUTE)     { return "IDREFS"; }
634        else if ( type == Attribute.ENTITY_ATTRIBUTE)     { return "ENTITY"; }
635        else if ( type == Attribute.ENTITIES_ATTRIBUTE)   { return "ENTITIES"; }
636        else if ( type == Attribute.NMTOKEN_ATTRIBUTE)    { return "NMTOKEN"; }
637        else if ( type == Attribute.NMTOKENS_ATTRIBUTE)   { return "NMTOKENS"; }
638        else if ( type == Attribute.NOTATION_ATTRIBUTE)   { return "NOTATION"; }
639        else if ( type == Attribute.ENUMERATED_ATTRIBUTE) { return "ENUMERATED"; }
640        else { return ""; }
641        
642    }
643 
644     private void traverseDOM(Element el) {
645         List attrList = el.getAttributes();
646         AttributesImpl   attrs = new AttributesImpl  ();
647         for (int i=0; i < attrList.size(); i++) {
648             Attribute attr =(Attribute)attrList.get(i);
649             attrs.addAttribute(attr.getNamespaceURI(), attr.getName(),
650                                getQualifiedName(attr), getAttributeType(attr),
651                                attr.getValue());
652         }
653 
654         startElement(el.getName(), attrs);
655 
656         // Add text node
657         String   text = el.getTextTrim();
658         if (text != null && text.length() != 0)
659             characters(text);
660 
661         List children = el.getChildren();
662         for (int i=0; i < children.size(); i++) 
663             traverseDOM((Element)children.get(i));
664 
665         endElement();
666 
667     }
668 
669 
670 }
671 
672
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags