/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.xerces.parsers;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Locale;

import org.apache.xerces.impl.Constants;
import org.apache.xerces.util.ParserConfigurationSettings;
import org.apache.xerces.util.SymbolTable;
import org.apache.xerces.xni.XMLDTDContentModelHandler;
import org.apache.xerces.xni.XMLDTDHandler;
import org.apache.xerces.xni.XMLDocumentHandler;
import org.apache.xerces.xni.XNIException;
import org.apache.xerces.xni.parser.XMLComponent;
import org.apache.xerces.xni.parser.XMLComponentManager;
import org.apache.xerces.xni.parser.XMLConfigurationException;
import org.apache.xerces.xni.parser.XMLDocumentSource;
import org.apache.xerces.xni.parser.XMLEntityResolver;
import org.apache.xerces.xni.parser.XMLErrorHandler;
import org.apache.xerces.xni.parser.XMLInputSource;
import org.apache.xerces.xni.parser.XMLParserConfiguration;

/**
 * A very basic parser configuration. This configuration class can
 * be used as a base class for custom parser configurations. The
 * basic parser configuration creates the symbol table (if not
 * specified at construction time) and manages all of the recognized
 * features and properties.
 * <p>
 * The basic parser configuration does <strong>not</strong> mandate
 * any particular pipeline configuration or the use of specific 
 * components except for the symbol table. If even this is too much
 * for a basic parser configuration, the programmer can create a new
 * configuration class that implements the 
 * <code>XMLParserConfiguration</code> interface.
 * <p>
 * Subclasses of the basic parser configuration can add their own
 * recognized features and properties by calling the
 * <code>addRecognizedFeature</code> and 
 * <code>addRecognizedProperty</code> methods, respectively.
 * <p>
 * The basic parser configuration assumes that the configuration
 * will be made up of various parser components that implement the
 * <code>XMLComponent</code> interface. If subclasses of this
 * configuration create their own components for use in the 
 * parser configuration, then each component should be added to
 * the list of components by calling the <code>addComponent</code>
 * method. The basic parser configuration will make sure to call
 * the <code>reset</code> method of each registered component
 * before parsing an instance document.
 * <p>
 * This class recognizes the following features and properties:
 * <ul>
 * <li>Features
 *  <ul>
 *   <li>http://xml.org/sax/features/validation</li>
 *   <li>http://xml.org/sax/features/namespaces</li>
 *   <li>http://xml.org/sax/features/external-general-entities</li>
 *   <li>http://xml.org/sax/features/external-parameter-entities</li>
 *  </ul>
 * <li>Properties
 *  <ul>
 *   <li>http://xml.org/sax/properties/xml-string</li>
 *   <li>http://apache.org/xml/properties/internal/symbol-table</li>
 *   <li>http://apache.org/xml/properties/internal/error-handler</li>
 *   <li>http://apache.org/xml/properties/internal/entity-resolver</li>
 *  </ul>
 * </ul>
 *
 * @author Arnaud  Le Hors, IBM
 * @author Andy Clark, IBM
 *
 * @version $Id: BasicParserConfiguration.java 447239 2006-09-18 05:08:26Z mrglavas $
 */
public abstract class BasicParserConfiguration
    extends ParserConfigurationSettings
    implements XMLParserConfiguration {

    //
    // Constants
    //

    // feature identifiers

    /** Feature identifier: validation. */
    protected static final String VALIDATION =
        Constants.SAX_FEATURE_PREFIX + Constants.VALIDATION_FEATURE;
    
    /** Feature identifier: namespaces. */
    protected static final String NAMESPACES =
        Constants.SAX_FEATURE_PREFIX + Constants.NAMESPACES_FEATURE;
    
    /** Feature identifier: external general entities. */
    protected static final String EXTERNAL_GENERAL_ENTITIES =
        Constants.SAX_FEATURE_PREFIX + Constants.EXTERNAL_GENERAL_ENTITIES_FEATURE;
    
    /** Feature identifier: external parameter entities. */
    protected static final String EXTERNAL_PARAMETER_ENTITIES =
        Constants.SAX_FEATURE_PREFIX + Constants.EXTERNAL_PARAMETER_ENTITIES_FEATURE;
    
    // property identifiers

    /** Property identifier: xml string. */
    protected static final String XML_STRING = 
        Constants.SAX_PROPERTY_PREFIX + Constants.XML_STRING_PROPERTY;

    /** Property identifier: symbol table. */
    protected static final String SYMBOL_TABLE = 
        Constants.XERCES_PROPERTY_PREFIX + Constants.SYMBOL_TABLE_PROPERTY;

    /** Property identifier: error handler. */
    protected static final String ERROR_HANDLER = 
        Constants.XERCES_PROPERTY_PREFIX + Constants.ERROR_HANDLER_PROPERTY;

    /** Property identifier: entity resolver. */
    protected static final String ENTITY_RESOLVER = 
        Constants.XERCES_PROPERTY_PREFIX + Constants.ENTITY_RESOLVER_PROPERTY;

    //
    // Data
    //

    // components (non-configurable)

    /** Symbol table. */
    protected SymbolTable fSymbolTable;


    // data

    /** Locale. */
    protected Locale fLocale;

    /** Components. */
    protected ArrayList fComponents;

    // handlers

    /** The document handler. */
    protected XMLDocumentHandler fDocumentHandler;

    /** The DTD handler. */
    protected XMLDTDHandler fDTDHandler;

    /** The DTD content model handler. */
    protected XMLDTDContentModelHandler fDTDContentModelHandler;

    /** Last component in the document pipeline */     
    protected XMLDocumentSource fLastComponent;

    //
    // Constructors
    //

    /** Default Constructor. */
    protected BasicParserConfiguration() {
        this(null, null);
    } // <init>()

    /** 
     * Constructs a parser configuration using the specified symbol table. 
     *
     * @param symbolTable The symbol table to use.
     */
    protected BasicParserConfiguration(SymbolTable symbolTable) {
        this(symbolTable, null);
    } // <init>(SymbolTable)

    /** 
     * Constructs a parser configuration using the specified symbol table
     * and parent settings.
     *
     * @param symbolTable    The symbol table to use.
     * @param parentSettings The parent settings.
     */
    protected BasicParserConfiguration(SymbolTable symbolTable,
                                       XMLComponentManager parentSettings) {
        super(parentSettings);

        // create a vector to hold all the components in use
        fComponents = new ArrayList();

        // create storage for recognized features and properties
        fRecognizedFeatures = new ArrayList();
        fRecognizedProperties = new ArrayList();

        // create table for features and properties
        fFeatures = new HashMap();
        fProperties = new HashMap();

        // add default recognized features
        final String[] recognizedFeatures = {
        	PARSER_SETTINGS,
            VALIDATION,                 
            NAMESPACES, 
            EXTERNAL_GENERAL_ENTITIES,  
            EXTERNAL_PARAMETER_ENTITIES,
        };
        addRecognizedFeatures(recognizedFeatures);
        fFeatures.put(PARSER_SETTINGS, Boolean.TRUE);
        // set state for default features
		fFeatures.put(VALIDATION, Boolean.FALSE);
		fFeatures.put(NAMESPACES, Boolean.TRUE);
		fFeatures.put(EXTERNAL_GENERAL_ENTITIES, Boolean.TRUE);
		fFeatures.put(EXTERNAL_PARAMETER_ENTITIES, Boolean.TRUE);

        // add default recognized properties
        final String[] recognizedProperties = {
            XML_STRING,     
            SYMBOL_TABLE,
            ERROR_HANDLER,  
            ENTITY_RESOLVER,
        };
        addRecognizedProperties(recognizedProperties);

        if (symbolTable == null) {
            symbolTable = new SymbolTable();
        }
        fSymbolTable = symbolTable;
        fProperties.put(SYMBOL_TABLE, fSymbolTable);

    } // <init>(SymbolTable)

    /** 
     * Adds a component to the parser configuration. This method will
     * also add all of the component's recognized features and properties
     * to the list of default recognized features and properties.
     *
     * @param component The component to add.
     */
    protected void addComponent(XMLComponent component) {

        // don't add a component more than once
        if (fComponents.contains(component)) {
            return;
        }
        fComponents.add(component);

        // register component's recognized features
        String[] recognizedFeatures = component.getRecognizedFeatures();
        addRecognizedFeatures(recognizedFeatures);
        
        // register component's recognized properties
        String[] recognizedProperties = component.getRecognizedProperties();
        addRecognizedProperties(recognizedProperties);

        // set default values
        if (recognizedFeatures != null) {
            for (int i = 0; i < recognizedFeatures.length; i++) {
                String featureId = recognizedFeatures[i];
                Boolean state = component.getFeatureDefault(featureId);
                if (state != null) {
                    super.setFeature(featureId, state.booleanValue());
                }
            }
        }
        if (recognizedProperties != null) {
            for (int i = 0; i < recognizedProperties.length; i++) {
                String propertyId = recognizedProperties[i];
                Object value = component.getPropertyDefault(propertyId);
                if (value != null) {
                    super.setProperty(propertyId, value);
                }
            }
        }

    } // addComponent(XMLComponent)

    //
    // XMLParserConfiguration methods
    //

    /**
     * Parse an XML document.
     * <p>
     * The parser can use this method to instruct this configuration
     * to begin parsing an XML document from any valid input source
     * (a character stream, a byte stream, or a URI).
     * <p>
     * Parsers may not invoke this method while a parse is in progress.
     * Once a parse is complete, the parser may then parse another XML
     * document.
     * <p>
     * This method is synchronous: it will not return until parsing
     * has ended.  If a client application wants to terminate 
     * parsing early, it should throw an exception.
     *
     * @param inputSource The input source for the top-level of the
     *               XML document.
     *
     * @exception XNIException Any XNI exception, possibly wrapping 
     *                         another exception.
     * @exception IOException  An IO exception from the parser, possibly
     *                         from a byte stream or character stream
     *                         supplied by the parser.
     */
    public abstract void parse(XMLInputSource inputSource) 
        throws XNIException, IOException;

    /**
     * Sets the document handler on the last component in the pipeline
     * to receive information about the document.
     * 
     * @param documentHandler   The document handler.
     */
    public void setDocumentHandler(XMLDocumentHandler documentHandler) {
        fDocumentHandler = documentHandler;
        if (fLastComponent != null) {
            fLastComponent.setDocumentHandler(fDocumentHandler);
            if (fDocumentHandler !=null){
                fDocumentHandler.setDocumentSource(fLastComponent);
            }
        }
    } // setDocumentHandler(XMLDocumentHandler)

    /** Returns the registered document handler. */
    public XMLDocumentHandler getDocumentHandler() {
        return fDocumentHandler;
    } // getDocumentHandler():XMLDocumentHandler

    /**
     * Sets the DTD handler.
     * 
     * @param dtdHandler The DTD handler.
     */
    public void setDTDHandler(XMLDTDHandler dtdHandler) {
        fDTDHandler = dtdHandler;
    } // setDTDHandler(XMLDTDHandler)

    /** Returns the registered DTD handler. */
    public XMLDTDHandler getDTDHandler() {
        return fDTDHandler;
    } // getDTDHandler():XMLDTDHandler

    /**
     * Sets the DTD content model handler.
     * 
     * @param handler The DTD content model handler.
     */
    public void setDTDContentModelHandler(XMLDTDContentModelHandler handler) {
        fDTDContentModelHandler = handler;
    } // setDTDContentModelHandler(XMLDTDContentModelHandler)

    /** Returns the registered DTD content model handler. */
    public XMLDTDContentModelHandler getDTDContentModelHandler() {
        return fDTDContentModelHandler;
    } // getDTDContentModelHandler():XMLDTDContentModelHandler

    /**
     * Sets the resolver used to resolve external entities. The EntityResolver
     * interface supports resolution of public and system identifiers.
     *
     * @param resolver The new entity resolver. Passing a null value will
     *                 uninstall the currently installed resolver.
     */
    public void setEntityResolver(XMLEntityResolver resolver) {
        // REVISIT: Should this be a property?
        fProperties.put(ENTITY_RESOLVER, resolver);
    } // setEntityResolver(XMLEntityResolver)

    /**
     * Return the current entity resolver.
     *
     * @return The current entity resolver, or null if none
     *         has been registered.
     * @see #setEntityResolver
     */
    public XMLEntityResolver getEntityResolver() {
        // REVISIT: Should this be a property?
        return (XMLEntityResolver)fProperties.get(ENTITY_RESOLVER);
    } // getEntityResolver():XMLEntityResolver

    /**
     * Allow an application to register an error event handler.
     *
     * <p>If the application does not register an error handler, all
     * error events reported by the SAX parser will be silently
     * ignored; however, normal processing may not continue.  It is
     * highly recommended that all SAX applications implement an
     * error handler to avoid unexpected bugs.</p>
     *
     * <p>Applications may register a new or different handler in the
     * middle of a parse, and the SAX parser must begin using the new
     * handler immediately.</p>
     *
     * @param errorHandler The error handler.
     * @exception java.lang.NullPointerException If the handler 
     *            argument is null.
     * @see #getErrorHandler
     */
    public void setErrorHandler(XMLErrorHandler errorHandler) {
        // REVISIT: Should this be a property?
        fProperties.put(ERROR_HANDLER, errorHandler);
    } // setErrorHandler(XMLErrorHandler)

    /**
     * Return the current error handler.
     *
     * @return The current error handler, or null if none
     *         has been registered.
     * @see #setErrorHandler
     */
    public XMLErrorHandler getErrorHandler() {
        // REVISIT: Should this be a property?
        return (XMLErrorHandler)fProperties.get(ERROR_HANDLER);
    } // getErrorHandler():XMLErrorHandler

    /**
     * Set the state of a feature.
     *
     * Set the state of any feature in a SAX2 parser.  The parser
     * might not recognize the feature, and if it does recognize
     * it, it might not be able to fulfill the request.
     *
     * @param featureId The unique identifier (URI) of the feature.
     * @param state The requested state of the feature (true or false).
     *
     * @exception org.apache.xerces.xni.parser.XMLConfigurationException If the
     *            requested feature is not known.
     */
    public void setFeature(String featureId, boolean state)
        throws XMLConfigurationException {

        // forward to every component
        int count = fComponents.size();
        for (int i = 0; i < count; i++) {
            XMLComponent c = (XMLComponent) fComponents.get(i);
            c.setFeature(featureId, state);
        }
        // save state if noone "objects"
        super.setFeature(featureId, state);

    } // setFeature(String,boolean)

    /**
     * setProperty
     * 
     * @param propertyId 
     * @param value 
     */
    public void setProperty(String propertyId, Object value)
        throws XMLConfigurationException {

        // forward to every component
        int count = fComponents.size();
        for (int i = 0; i < count; i++) {
            XMLComponent c = (XMLComponent) fComponents.get(i);
            c.setProperty(propertyId, value);
        }

        // store value if noone "objects"
        super.setProperty(propertyId, value);

    } // setProperty(String,Object)

    /**
     * Set the locale to use for messages.
     *
     * @param locale The locale object to use for localization of messages.
     *
     * @exception XNIException Thrown if the parser does not support the
     *                         specified locale.
     */
    public void setLocale(Locale locale) throws XNIException {
        fLocale = locale;
    } // setLocale(Locale)

    /** Returns the locale. */
    public Locale getLocale() {
        return fLocale;
    } // getLocale():Locale

    //
    // Protected methods
    //

    /**
     * reset all components before parsing and namespace context
     */
    protected void reset() throws XNIException {

        // reset every component
        int count = fComponents.size();
        for (int i = 0; i < count; i++) {
            XMLComponent c = (XMLComponent) fComponents.get(i);
            c.reset(this);
        }

    } // reset()

    /**
     * Check a property. If the property is known and supported, this method
     * simply returns. Otherwise, the appropriate exception is thrown.
     *
     * @param propertyId The unique identifier (URI) of the property
     *                   being set.
     * @exception org.apache.xerces.xni.parser.XMLConfigurationException If the
     *            requested feature is not known or supported.
     */
    protected void checkProperty(String propertyId)
        throws XMLConfigurationException {

        // special cases
        if (propertyId.startsWith(Constants.SAX_PROPERTY_PREFIX)) {
            final int suffixLength = propertyId.length() - Constants.SAX_PROPERTY_PREFIX.length();	
        	
            //
            // http://xml.org/sax/properties/xml-string
            // Value type: String
            // Access: read-only
            //   Get the literal string of characters associated with the
            //   current event.  If the parser recognises and supports this
            //   property but is not currently parsing text, it should return
            //   null (this is a good way to check for availability before the
            //   parse begins).
            //
            if (suffixLength == Constants.XML_STRING_PROPERTY.length() && 
                propertyId.endsWith(Constants.XML_STRING_PROPERTY)) {
                // REVISIT - we should probably ask xml-dev for a precise
                // definition of what this is actually supposed to return, and
                // in exactly which circumstances.
                short type = XMLConfigurationException.NOT_SUPPORTED;
                throw new XMLConfigurationException(type, propertyId);
            }
        }

        // check property
        super.checkProperty(propertyId);

    } // checkProperty(String)
    
    
    /**
     * Check a feature. If feature is know and supported, this method simply
     * returns. Otherwise, the appropriate exception is thrown.
     *
     * @param featureId The unique identifier (URI) of the feature.
     *
     * @throws XMLConfigurationException Thrown for configuration error.
     *                                   In general, components should
     *                                   only throw this exception if
     *                                   it is <strong>really</strong>
     *                                   a critical error.
     */
    protected void checkFeature(String featureId)
        throws XMLConfigurationException {

        //
        // Xerces Features
        //
        if (featureId.startsWith(Constants.XERCES_FEATURE_PREFIX)) {
            final int suffixLength = featureId.length() - Constants.XERCES_FEATURE_PREFIX.length();

            //
            // special performance feature: no one by component manager is allowed to set it
            //
            if (suffixLength == Constants.PARSER_SETTINGS.length() && 
                featureId.endsWith(Constants.PARSER_SETTINGS)) {
                short type = XMLConfigurationException.NOT_SUPPORTED;
                throw new XMLConfigurationException(type, featureId);
            }
        }

        super.checkFeature(featureId);

     } // checkFeature(String)


} // class BasicParserConfiguration
