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/*
 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package com.sun.tools.internal.jxc.gen.config;

import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Stack;
import java.util.StringTokenizer;

import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;


Runtime Engine for RELAXNGCC execution.
This class has the following functionalities:

    
 
  1. Managing a stack of NGCCHandler objects and
     switching between them appropriately.
 
  2. Keep track of all Attributes.
 
  3. manage mapping between namespace URIs and prefixes.
 
  4. TODO: provide support for interleaving.




    Auto-generated, do not edit.



Author:Kohsuke Kawaguchi (kk@kohsuke.org)
Version:$Id: NGCCRuntime.java,v 1.15 2002/09/29 02:55:48 okajima Exp $
/**
 * Runtime Engine for RELAXNGCC execution.
 *
 * This class has the following functionalities:
 *
 * <ol>
 *  <li>Managing a stack of NGCCHandler objects and
 *      switching between them appropriately.
 *
 *  <li>Keep track of all Attributes.
 *
 *  <li>manage mapping between namespace URIs and prefixes.
 *
 *  <li>TODO: provide support for interleaving.
 * </ol>
 * <p><b>
 *     Auto-generated, do not edit.
 * </b></p>
 * @version $Id: NGCCRuntime.java,v 1.15 2002/09/29 02:55:48 okajima Exp $
 * @author Kohsuke Kawaguchi (kk@kohsuke.org)
 */
public class NGCCRuntime implements ContentHandler, NGCCEventSource {

    public NGCCRuntime() {
        reset();
    }

    
Sets the root handler, which will be used to parse the
root element.


This method can be called right after the object is created
or the reset method is called. You can't replace the root
handler while parsing is in progress.

 Usually a generated class that corresponds to the <start> pattern will be used as the root handler, but any NGCCHandler can be a root handler. 
Throws:
  • IllegalStateException – 
     If this method is called but it doesn't satisfy the
     pre-condition stated above.
/**
     * Sets the root handler, which will be used to parse the
     * root element.
     * <p>
     * This method can be called right after the object is created
     * or the reset method is called. You can't replace the root
     * handler while parsing is in progress.
     * <p>
     * Usually a generated class that corresponds to the {@code <start>}
     * pattern will be used as the root handler, but any NGCCHandler
     * can be a root handler.
     *
     * @exception IllegalStateException
     *      If this method is called but it doesn't satisfy the
     *      pre-condition stated above.
     */
    public void setRootHandler( NGCCHandler rootHandler ) {
        if(currentHandler!=null)
            throw new IllegalStateException();
        currentHandler = rootHandler;
    }


    
Cleans up all the data structure so that the object can be reused later.
Normally, applications do not need to call this method directly,
as the runtime resets itself after the endDocument method.

/**
     * Cleans up all the data structure so that the object can be reused later.
     * Normally, applications do not need to call this method directly,
     *
     * as the runtime resets itself after the endDocument method.
     */
    public void reset() {
        attStack.clear();
        currentAtts = null;
        currentHandler = null;
        indent=0;
        locator = null;
        namespaces.clear();
        needIndent = true;
        redirect = null;
        redirectionDepth = 0;
        text = new StringBuffer();

        // add a dummy attributes at the bottom as a "centinel."
        attStack.push(new AttributesImpl());
    }

    // current content handler can be acccessed via set/getContentHandler.

    private Locator locator;
    public void setDocumentLocator( Locator _loc ) { this.locator=_loc; }
    
Gets the source location of the current event.


One can call this method from RelaxNGCC handlers to access
the line number information. Note that to

/**
     * Gets the source location of the current event.
     *
     * <p>
     * One can call this method from RelaxNGCC handlers to access
     * the line number information. Note that to
     */
    public Locator getLocator() { return locator; }


    
stack of Attributes. 
/** stack of {@link Attributes}. */
    private final Stack attStack = new Stack();
    
current attributes set. always equal to attStack.peek() 
/** current attributes set. always equal to attStack.peek() */
    private AttributesImpl currentAtts;

    
Attributes that belong to the current element.


It's generally not recommended for applications to use
this method. RelaxNGCC internally removes processed attributes,
so this doesn't correctly reflect all the attributes an element
carries.

/**
     * Attributes that belong to the current element.
     * <p>
     * It's generally not recommended for applications to use
     * this method. RelaxNGCC internally removes processed attributes,
     * so this doesn't correctly reflect all the attributes an element
     * carries.
     */
    public Attributes getCurrentAttributes() {
        return currentAtts;
    }

    
accumulated text. 
/** accumulated text. */
    private StringBuffer text = new StringBuffer();




    
The current NGCCHandler. Always equals to handlerStack.peek() 
/** The current NGCCHandler. Always equals to handlerStack.peek() */
    private NGCCEventReceiver currentHandler;

    public int replace( NGCCEventReceiver o, NGCCEventReceiver n ) {
        if(o!=currentHandler)
            throw new IllegalStateException();  // bug of RelaxNGCC
        currentHandler = n;

        return 0;   // we only have one thread.
    }

    
Processes buffered text.
This method will be called by the start/endElement event to process
buffered text as a text event.


Whitespace handling is a tricky business. Consider the following
schema fragment:


<element name="foo">
  <choice>
    <element name="bar"><empty/></element>
    <text/>
  </choice>
</element>


Assume we hit the following instance:


<foo> <bar/></foo>


Then this first space needs to be ignored (for otherwise, we will
end up treating this space as the match to <text/> and won't
be able to process <bar>.)
Now assume the following instance:


<foo/>


This time, we need to treat this empty string as a text, for
otherwise we won't be able to accept this instance.


This is very difficult to solve in general, but one seemingly
easy solution is to use the type of next event. If a text is
followed by a start tag, it follows from the constraint on
RELAX NG that that text must be either whitespaces or a match
to <text/>.


On the contrary, if a text is followed by a end tag, then it
cannot be whitespace unless the content model can accept empty,
in which case sending a text event will be harmlessly ignored
by the NGCCHandler.


Thus this method take one parameter, which controls the
behavior of this method.


TODO: according to the constraint of RELAX NG, if characters
follow an end tag, then they must be either whitespaces or
must match to <text/>.

Params:
  • possiblyWhitespace – 
     True if the buffered character can be ignorabale. False if
     it needs to be consumed.
/**
     * Processes buffered text.
     *
     * This method will be called by the start/endElement event to process
     * buffered text as a text event.
     *
     * <p>
     * Whitespace handling is a tricky business. Consider the following
     * schema fragment:
     *
     * <pre>{@code
     * <element name="foo">
     *   <choice>
     *     <element name="bar"><empty/></element>
     *     <text/>
     *   </choice>
     * </element>
     * }</pre>
     *
     * Assume we hit the following instance:
     * <pre>{@code
     * <foo> <bar/></foo>
     * }</pre>
     *
     * Then this first space needs to be ignored (for otherwise, we will
     * end up treating this space as the match to &lt;text/> and won't
     * be able to process &lt;bar>.)
     *
     * Now assume the following instance:
     * <pre>{@code
     * <foo/>
     * }</pre>
     *
     * This time, we need to treat this empty string as a text, for
     * otherwise we won't be able to accept this instance.
     *
     * <p>
     * This is very difficult to solve in general, but one seemingly
     * easy solution is to use the type of next event. If a text is
     * followed by a start tag, it follows from the constraint on
     * RELAX NG that that text must be either whitespaces or a match
     * to &lt;text/>.
     *
     * <p>
     * On the contrary, if a text is followed by a end tag, then it
     * cannot be whitespace unless the content model can accept empty,
     * in which case sending a text event will be harmlessly ignored
     * by the NGCCHandler.
     *
     * <p>
     * Thus this method take one parameter, which controls the
     * behavior of this method.
     *
     * <p>
     * TODO: according to the constraint of RELAX NG, if characters
     * follow an end tag, then they must be either whitespaces or
     * must match to &lt;text/>.
     *
     * @param   possiblyWhitespace
     *      True if the buffered character can be ignorabale. False if
     *      it needs to be consumed.
     */
    private void processPendingText(boolean ignorable) throws SAXException {
        if(ignorable && text.toString().trim().length()==0)
            ; // ignore. See the above javadoc comment for the description
        else
            currentHandler.text(text.toString());   // otherwise consume this token

        // truncate StringBuffer, but avoid excessive allocation.
        if(text.length()>1024)  text = new StringBuffer();
        else                    text.setLength(0);
    }

    public void processList( String str ) throws SAXException {
        StringTokenizer t = new StringTokenizer(str, " \t\r\n");
        while(t.hasMoreTokens())
            currentHandler.text(t.nextToken());
    }

    public void startElement(String uri, String localname, String qname, Attributes atts)
            throws SAXException {

        if(redirect!=null) {
            redirect.startElement(uri,localname,qname,atts);
            redirectionDepth++;
        } else {
            processPendingText(true);
            //        System.out.println("startElement:"+localname+"->"+_attrStack.size());
            currentHandler.enterElement(uri, localname, qname, atts);
        }
    }

    
Called by the generated handler code when an enter element
event is consumed.


Pushes a new attribute set.


Note that attributes are NOT pushed at the startElement method,
because the processing of the enterElement event can trigger
other attribute events and etc.


This method will be called from one of handlers when it truely
consumes the enterElement event.

/**
     * Called by the generated handler code when an enter element
     * event is consumed.
     *
     * <p>
     * Pushes a new attribute set.
     *
     * <p>
     * Note that attributes are NOT pushed at the startElement method,
     * because the processing of the enterElement event can trigger
     * other attribute events and etc.
     * <p>
     * This method will be called from one of handlers when it truely
     * consumes the enterElement event.
     */
    public void onEnterElementConsumed(
            String uri, String localName, String qname,Attributes atts) throws SAXException {
        attStack.push(currentAtts=new AttributesImpl(atts));
        nsEffectiveStack.push( new Integer(nsEffectivePtr) );
        nsEffectivePtr = namespaces.size();
    }

    public void onLeaveElementConsumed(String uri, String localName, String qname) throws SAXException {
        attStack.pop();
        if(attStack.isEmpty())
            currentAtts = null;
        else
            currentAtts = (AttributesImpl)attStack.peek();
        nsEffectivePtr = ((Integer)nsEffectiveStack.pop()).intValue();
    }

    public void endElement(String uri, String localname, String qname)
            throws SAXException {

        if(redirect!=null) {
            redirect.endElement(uri,localname,qname);
            redirectionDepth--;

            if(redirectionDepth!=0)
                return;

            // finished redirection.
            for( int i=0; i<namespaces.size(); i+=2 )
                redirect.endPrefixMapping((String)namespaces.get(i));
            redirect.endDocument();

            redirect = null;
            // then process this element normally
        }

        processPendingText(false);

        currentHandler.leaveElement(uri, localname, qname);
//        System.out.println("endElement:"+localname);
    }

    public void characters(char[] ch, int start, int length) throws SAXException {
        if(redirect!=null)
            redirect.characters(ch,start,length);
        else
            text.append(ch,start,length);
    }
    public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException {
        if(redirect!=null)
            redirect.ignorableWhitespace(ch,start,length);
        else
            text.append(ch,start,length);
    }

    public int getAttributeIndex(String uri, String localname) {
        return currentAtts.getIndex(uri, localname);
    }
    public void consumeAttribute(int index) throws SAXException {
        final String uri    = currentAtts.getURI(index);
        final String local  = currentAtts.getLocalName(index);
        final String qname  = currentAtts.getQName(index);
        final String value  = currentAtts.getValue(index);
        currentAtts.removeAttribute(index);

        currentHandler.enterAttribute(uri,local,qname);
        currentHandler.text(value);
        currentHandler.leaveAttribute(uri,local,qname);
    }


    public void startPrefixMapping( String prefix, String uri ) throws SAXException {
        if(redirect!=null)
            redirect.startPrefixMapping(prefix,uri);
        else {
            namespaces.add(prefix);
            namespaces.add(uri);
        }
    }

    public void endPrefixMapping( String prefix ) throws SAXException {
        if(redirect!=null)
            redirect.endPrefixMapping(prefix);
        else {
            namespaces.remove(namespaces.size()-1);
            namespaces.remove(namespaces.size()-1);
        }
    }

    public void skippedEntity( String name ) throws SAXException {
        if(redirect!=null)
            redirect.skippedEntity(name);
    }

    public void processingInstruction( String target, String data ) throws SAXException {
        if(redirect!=null)
            redirect.processingInstruction(target,data);
    }

    
Impossible token. This value can never be a valid XML name. 
/** Impossible token. This value can never be a valid XML name. */
    static final String IMPOSSIBLE = "\u0000";

    public void endDocument() throws SAXException {
        // consume the special "end document" token so that all the handlers
        // currently at the stack will revert to their respective parents.
        //
        // this is necessary to handle a grammar like
        // <start><ref name="X"/></start>
        // <define name="X">
        //   <element name="root"><empty/></element>
        // </define>
        //
        // With this grammar, when the endElement event is consumed, two handlers
        // are on the stack (because a child object won't revert to its parent
        // unless it sees a next event.)

        // pass around an "impossible" token.
        currentHandler.leaveElement(IMPOSSIBLE,IMPOSSIBLE,IMPOSSIBLE);

        reset();
    }
    public void startDocument() {}




//
//
// event dispatching methods
//
//

    public void sendEnterAttribute( int threadId,
                                    String uri, String local, String qname) throws SAXException {

        currentHandler.enterAttribute(uri,local,qname);
    }

    public void sendEnterElement( int threadId,
                                  String uri, String local, String qname, Attributes atts) throws SAXException {

        currentHandler.enterElement(uri,local,qname,atts);
    }

    public void sendLeaveAttribute( int threadId,
                                    String uri, String local, String qname) throws SAXException {

        currentHandler.leaveAttribute(uri,local,qname);
    }

    public void sendLeaveElement( int threadId,
                                  String uri, String local, String qname) throws SAXException {

        currentHandler.leaveElement(uri,local,qname);
    }

    public void sendText(int threadId, String value) throws SAXException {
        currentHandler.text(value);
    }


//
//
// redirection of SAX2 events.
//
//
    
When redirecting a sub-tree, this value will be non-null. 
/** When redirecting a sub-tree, this value will be non-null. */
    private ContentHandler redirect = null;

    
Counts the depth of the elements when we are re-directing
a sub-tree to another ContentHandler.

/**
     * Counts the depth of the elements when we are re-directing
     * a sub-tree to another ContentHandler.
     */
    private int redirectionDepth = 0;

    
This method can be called only from the enterElement handler.
The sub-tree rooted at the new element will be redirected
to the specified ContentHandler.


Currently active NGCCHandler will only receive the leaveElement
event of the newly started element.

@param  uri,local,qname
     Parameters passed to the enter element event. Used to
     simulate the startElement event for the new ContentHandler.
/**
     * This method can be called only from the enterElement handler.
     * The sub-tree rooted at the new element will be redirected
     * to the specified ContentHandler.
     *
     * <p>
     * Currently active NGCCHandler will only receive the leaveElement
     * event of the newly started element.
     *
     * @param   uri,local,qname
     *      Parameters passed to the enter element event. Used to
     *      simulate the startElement event for the new ContentHandler.
     */
    public void redirectSubtree( ContentHandler child,
                                 String uri, String local, String qname ) throws SAXException {

        redirect = child;
        redirect.setDocumentLocator(locator);
        redirect.startDocument();

        // TODO: when a prefix is re-bound to something else,
        // the following code is potentially dangerous. It should be
        // modified to report active bindings only.
        for( int i=0; i<namespaces.size(); i+=2 )
            redirect.startPrefixMapping(
                    (String)namespaces.get(i),
                    (String)namespaces.get(i+1)
            );

        redirect.startElement(uri,local,qname,currentAtts);
        redirectionDepth=1;
    }

//
//
// validation context implementation
//
//
    
in-scope namespace mapping.
namespaces[2n  ] := prefix
namespaces[2n+1] := namespace URI 
/** in-scope namespace mapping.
     * namespaces[2n  ] := prefix
     * namespaces[2n+1] := namespace URI */
    private final ArrayList namespaces = new ArrayList();
    
Index on the namespaces array, which points to the top of the effective bindings. Because of the timing difference between the startPrefixMapping method and the execution of the corresponding actions, this value can be different from namespaces.size(). 

For example, consider the following schema:


 <oneOrMore>
  <element name="foo"><empty/></element>
 </oneOrMore>
 code fragment X
 <element name="bob"/>


Code fragment X is executed after we see a startElement event,
but at this time the namespaces variable already include new
namespace bindings declared on "bob".

/**
     * Index on the namespaces array, which points to
     * the top of the effective bindings. Because of the
     * timing difference between the startPrefixMapping method
     * and the execution of the corresponding actions,
     * this value can be different from {@code namespaces.size()}.
     * <p>
     * For example, consider the following schema:
     * <pre>{@code
     *  <oneOrMore>
     *   <element name="foo"><empty/></element>
     *  </oneOrMore>
     *  code fragment X
     *  <element name="bob"/>
     * }</pre>
     * Code fragment X is executed after we see a startElement event,
     * but at this time the namespaces variable already include new
     * namespace bindings declared on "bob".
     */
    private int nsEffectivePtr=0;

    
Stack to preserve old nsEffectivePtr values.

/**
     * Stack to preserve old nsEffectivePtr values.
     */
    private final Stack nsEffectiveStack = new Stack();

    public String resolveNamespacePrefix( String prefix ) {
        for( int i = nsEffectivePtr-2; i>=0; i-=2 )
            if( namespaces.get(i).equals(prefix) )
                return (String)namespaces.get(i+1);

        // no binding was found.
        if(prefix.equals(""))   return "";  // return the default no-namespace
        if(prefix.equals("xml"))    // pre-defined xml prefix
            return "http://www.w3.org/XML/1998/namespace";
        else    return null;    // prefix undefined
    }


    // error reporting
    protected void unexpectedX(String token) throws SAXException {
        throw new SAXParseException(MessageFormat.format(
                "Unexpected {0} appears at line {1} column {2}",
                new Object[]{
                        token,
                        new Integer(getLocator().getLineNumber()),
                        new Integer(getLocator().getColumnNumber()) }),
                getLocator());
    }




    //
//
// trace functions
//
//
    private int indent=0;
    private boolean needIndent=true;
    private void printIndent() {
        for( int i=0; i<indent; i++ )
            System.out.print("  ");
    }
    public void trace( String s ) {
        if(needIndent) {
            needIndent=false;
            printIndent();
        }
        System.out.print(s);
    }
    public void traceln( String s ) {
        trace(s);
        trace("\n");
        needIndent=true;
    }
}