xpointerhandler.java

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/*
 * Copyright 2005 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.sun.org.apache.xerces.internal.xpointer;

import java.util.Hashtable;
import java.util.Vector;

import com.sun.org.apache.xerces.internal.impl.Constants;
import com.sun.org.apache.xerces.internal.impl.XMLErrorReporter;
import com.sun.org.apache.xerces.internal.util.SymbolTable;
import com.sun.org.apache.xerces.internal.util.XMLChar;
import com.sun.org.apache.xerces.internal.util.XMLSymbols;
import com.sun.org.apache.xerces.internal.xinclude.XIncludeHandler;
import com.sun.org.apache.xerces.internal.xinclude.XIncludeNamespaceSupport;
import com.sun.org.apache.xerces.internal.xni.Augmentations;
import com.sun.org.apache.xerces.internal.xni.QName;
import com.sun.org.apache.xerces.internal.xni.XMLAttributes;
import com.sun.org.apache.xerces.internal.xni.XMLString;
import com.sun.org.apache.xerces.internal.xni.XNIException;
import com.sun.org.apache.xerces.internal.xni.parser.XMLConfigurationException;
import com.sun.org.apache.xerces.internal.xni.parser.XMLErrorHandler;

/**
 * <p>
 * This is a pipeline component which extends the XIncludeHandler to perform 
 * XPointer specific processing specified in the W3C XPointerFramework and 
 * element() Scheme Recommendations.
 * </p>
 * 
 * <p>
 * This component analyzes each event in the pipeline, looking for an element 
 * that matches a PointerPart in the parent XInclude element's xpointer attribute  
 * value.  If the match succeeds, all children are passed by this component.
 * </p>
 * 
 * <p>
 * See the <a href="http://www.w3.org/TR/xptr-framework//">XPointer Framework Recommendation</a> for
 * more information on the XPointer Framework and ShortHand Pointers.
 * See the <a href="http://www.w3.org/TR/xptr-element/">XPointer element() Scheme Recommendation</a> for
 * more information on the XPointer element() Scheme. 
 * </p>  
 *
 * @xerces.internal
 * 
 * @version $Id: XPointerHandler.java,v 1.1.4.1 2005/09/08 05:25:44 sunithareddy Exp $
 */
public final class XPointerHandler extends XIncludeHandler implements
        XPointerProcessor {

    // Fields
    // A Vector of XPointerParts  
    protected Vector fXPointerParts = null;

    // The current XPointerPart  
    protected XPointerPart fXPointerPart = null;

    // Has the fXPointerPart resolved successfully
    protected boolean fFoundMatchingPtrPart = false;

    // The XPointer Error reporter
    protected XMLErrorReporter fXPointerErrorReporter;

    // The XPointer Error Handler
    protected XMLErrorHandler fErrorHandler;

    // XPointerFramework symbol table
    protected SymbolTable fSymbolTable = null;

    // Supported schemes
    private final String ELEMENT_SCHEME_NAME = "element";

   // Has the XPointer resolved the subresource
    protected boolean fIsXPointerResolved = false;
    
    // Fixup xml:base and xml:lang attributes
    protected boolean fFixupBase = false;
    protected boolean fFixupLang = false;
    
    // ************************************************************************
    // Constructors
    // ************************************************************************

    /**
     *  
     */
    public XPointerHandler() {
        super();

        fXPointerParts = new Vector();
        fSymbolTable = new SymbolTable();
    }

    public XPointerHandler(SymbolTable symbolTable,
            XMLErrorHandler errorHandler, XMLErrorReporter errorReporter) {
        super();

        fXPointerParts = new Vector();
        fSymbolTable = symbolTable;
        fErrorHandler = errorHandler;
        fXPointerErrorReporter = errorReporter;
        //fErrorReporter = errorReporter; // The XInclude ErrorReporter
    }
    
    // ************************************************************************
    //  Implementation of the XPointerProcessor interface.
    // ************************************************************************

    /** 
     * Parses the XPointer framework expression and delegates scheme specific parsing. 
     *   
     * @see com.sun.org.apache.xerces.internal.xpointer.XPointerProcessor#parseXPointer(java.lang.String)
     */
    public void parseXPointer(String xpointer) throws XNIException {

        // Initialize
        init();

        // tokens
        final Tokens tokens = new Tokens(fSymbolTable);

        // scanner
        Scanner scanner = new Scanner(fSymbolTable) {
            protected void addToken(Tokens tokens, int token)
                    throws XNIException {
                if (token == Tokens.XPTRTOKEN_OPEN_PAREN
                        || token == Tokens.XPTRTOKEN_CLOSE_PAREN
                        || token == Tokens.XPTRTOKEN_SCHEMENAME
                        || token == Tokens.XPTRTOKEN_SCHEMEDATA
                        || token == Tokens.XPTRTOKEN_SHORTHAND) {
                    super.addToken(tokens, token);
                    return;
                }
                reportError("InvalidXPointerToken", new Object[] { tokens
                        .getTokenString(token) });
            }
        };

        // scan the XPointer expression
        int length = xpointer.length();
        boolean success = scanner.scanExpr(fSymbolTable, tokens, xpointer, 0,
                length);

        if (!success)
            reportError("InvalidXPointerExpression", new Object[] { xpointer });

        while (tokens.hasMore()) {
            int token = tokens.nextToken();

            switch (token) {
            case Tokens.XPTRTOKEN_SHORTHAND: {

                // The shortHand name
                token = tokens.nextToken();
                String shortHandPointerName = tokens.getTokenString(token);

                if (shortHandPointerName == null) {
                    reportError("InvalidXPointerExpression",
                            new Object[] { xpointer });
                }

                XPointerPart shortHandPointer = new ShortHandPointer(
                        fSymbolTable);
                shortHandPointer.setSchemeName(shortHandPointerName);
                fXPointerParts.add(shortHandPointer);
                break;
            }
            case Tokens.XPTRTOKEN_SCHEMENAME: {

                // Retreive the local name and prefix to form the scheme name
                token = tokens.nextToken();
                String prefix = tokens.getTokenString(token);
                token = tokens.nextToken();
                String localName = tokens.getTokenString(token);

                String schemeName = prefix + localName;

                // The next character should be an open parenthesis
                int openParenCount = 0;
                int closeParenCount = 0;

                token = tokens.nextToken();
                String openParen = tokens.getTokenString(token);
                if (openParen != "XPTRTOKEN_OPEN_PAREN") {

                    // can not have more than one ShortHand Pointer
                    if (token == Tokens.XPTRTOKEN_SHORTHAND) {
                        reportError("MultipleShortHandPointers",
                                new Object[] { xpointer });
                    } else {
                        reportError("InvalidXPointerExpression",
                                new Object[] { xpointer });
                    }
                }
                openParenCount++;

                // followed by zero or more ( and  the schemeData
                String schemeData = null;
                while (tokens.hasMore()) {
                    token = tokens.nextToken();
                    schemeData = tokens.getTokenString(token);
                    if (schemeData != "XPTRTOKEN_OPEN_PAREN") {
                        break;
                    }
                    openParenCount++;
                }
                token = tokens.nextToken();
                schemeData = tokens.getTokenString(token);

                // followed by the same number of )
                token = tokens.nextToken();
                String closeParen = tokens.getTokenString(token);
                if (closeParen != "XPTRTOKEN_CLOSE_PAREN") {
                    reportError("SchemeDataNotFollowedByCloseParenthesis",
                            new Object[] { xpointer });
                }
                closeParenCount++;

                while (tokens.hasMore()) {
                    if (tokens.getTokenString(tokens.peekToken()) != "XPTRTOKEN_OPEN_PAREN") {
                        break;
                    }
                    closeParenCount++;
                }

                // check if the number of open parenthesis are equal to the number of close parenthesis
                if (openParenCount != closeParenCount) {
                    reportError("UnbalancedParenthesisInXPointerExpression",
                            new Object[] { xpointer,
                                    new Integer(openParenCount),
                                    new Integer(closeParenCount) });
                }

                // Perform scheme specific parsing of the pointer part
                if (schemeName.equals(ELEMENT_SCHEME_NAME)) {
                    XPointerPart elementSchemePointer = new ElementSchemePointer(
                            fSymbolTable, fErrorReporter);
                    elementSchemePointer.setSchemeName(schemeName);
                    elementSchemePointer.setSchemeData(schemeData);

                    // If an exception occurs while parsing the element() scheme expression
                    // ignore it and move on to the next pointer part
                    try {
                        elementSchemePointer.parseXPointer(schemeData);
                        fXPointerParts.add(elementSchemePointer);
                    } catch (XNIException e) {
                        // Re-throw the XPointer element() scheme syntax error.
                    	throw new XNIException (e);
                    }

                } else {
                    // ????
                    reportWarning("SchemeUnsupported",
                            new Object[] { schemeName });
                }

                break;
            }
            default:
                reportError("InvalidXPointerExpression",
                        new Object[] { xpointer });
            }
        }

    }

    /**
     *  
     * @see com.sun.org.apache.xerces.internal.xpointer.XPointerProcessor#resolveXPointer(com.sun.org.apache.xerces.internal.xni.QName, com.sun.org.apache.xerces.internal.xni.XMLAttributes, com.sun.org.apache.xerces.internal.xni.Augmentations, int event)
     */
    public boolean resolveXPointer(QName element, XMLAttributes attributes,
            Augmentations augs, int event) throws XNIException {
    	boolean resolved = false;
    	
        // The result of the first pointer part whose evaluation identifies 
        // one or more subresources is reported by the XPointer processor as the 
        // result of the pointer as a whole, and evaluation stops.
        // In our implementation, typically the first xpointer scheme that 
        // matches an element is the document is considered.
        // If the pointer part resolved then use it, else search for the fragment
        // using next pointer part from lef-right.
        if (!fFoundMatchingPtrPart) {

            // for each element, attempt to resolve it against each pointer part 
            // in the XPointer expression until a matching element is found.
            for (int i = 0; i < fXPointerParts.size(); i++) {

                fXPointerPart = (XPointerPart) fXPointerParts.get(i);

                if (fXPointerPart.resolveXPointer(element, attributes, augs,
                        event)) {
                    fFoundMatchingPtrPart = true;
                    resolved = true;
                }
            }
        } else {
            if (fXPointerPart.resolveXPointer(element, attributes, augs, event)) {
            	resolved = true;
            }
        }