basicparserconfiguration.java

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/*
 * Copyright 2001-2004 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.parsers;

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

import com.sun.org.apache.xerces.internal.impl.Constants;
import com.sun.org.apache.xerces.internal.util.ParserConfigurationSettings;
import com.sun.org.apache.xerces.internal.util.SymbolTable;
import com.sun.org.apache.xerces.internal.xni.XMLDTDContentModelHandler;
import com.sun.org.apache.xerces.internal.xni.XMLDTDHandler;
import com.sun.org.apache.xerces.internal.xni.XMLDocumentHandler;
import com.sun.org.apache.xerces.internal.xni.XNIException;
import com.sun.org.apache.xerces.internal.xni.parser.XMLComponent;
import com.sun.org.apache.xerces.internal.xni.parser.XMLComponentManager;
import com.sun.org.apache.xerces.internal.xni.parser.XMLConfigurationException;
import com.sun.org.apache.xerces.internal.xni.parser.XMLDocumentSource;
import com.sun.org.apache.xerces.internal.xni.parser.XMLEntityResolver;
import com.sun.org.apache.xerces.internal.xni.parser.XMLErrorHandler;
import com.sun.org.apache.xerces.internal.xni.parser.XMLInputSource;
import com.sun.org.apache.xerces.internal.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,v 1.2.6.1 2005/09/06 12:53:19 sunithareddy Exp $
 */
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