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ARQ is a SPARQL 1.1 query engine for Apache Jena
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/**
 * 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.jena.riot;

import static org.apache.jena.riot.RDFLanguages.* ;

import java.io.InputStream ;
import java.io.Reader ;
import java.util.Map ;
import java.util.Set ;

import org.apache.jena.atlas.lib.DS ;
import org.apache.jena.atlas.lib.InternalErrorException ;
import org.apache.jena.atlas.web.ContentType ;
import org.apache.jena.riot.lang.* ;
import org.apache.jena.riot.system.ErrorHandler ;
import org.apache.jena.riot.system.ErrorHandlerFactory ;
import org.apache.jena.riot.system.ParserProfile ;
import org.apache.jena.riot.system.StreamRDF ;
import org.apache.jena.riot.thrift.BinRDF ;
import org.apache.jena.sparql.util.Context ;

/** The registry of languages and parsers.
 * To register a new parser:
 * 
 * Register the language with {@link RDFLanguages}
 * Register the parser factory with {@link RDFParserRegistry}
 * 
 */

public class RDFParserRegistry
{
    /** Map Jena I/O names to language */
    private static Map mapJenaNameToLang                 = DS.map() ;

    /** map language to a parser factory */ 
    private static Map langToParserFactory  = DS.map() ;
    
    /** Known triples languages */
    private static Set langTriples  = DS.set() ;

    /** Known quads languages */
    private static Set langQuads    = DS.set() ;

    /** Generic parser factory. */
    private static ReaderRIOTFactory parserFactory          = new ReaderRIOTFactoryImpl() ;
    private static ReaderRIOTFactory parserFactoryJsonLD    = new ReaderRIOTFactoryJSONLD() ;
    private static ReaderRIOTFactory parserFactoryThrift    = new ReaderRIOTFactoryThrift() ;
    private static ReaderRIOTFactory parserFactoryTriX      = new ReaderRIOTFactoryTriX() ;
    private static ReaderRIOTFactory parserFactoryRDFNULL   = new ReaderRIOTFactoryRDFNULL() ;
        
    private static boolean initialized = false ;
    static { init() ; }
    public static void init()
    {
        if ( initialized ) return ;
        initialized = true ;
        initStandard() ;
    }
    
    private static void initStandard()
    {
        // Make sure the constants are initialized.
        RDFLanguages.init() ;
        
        registerLangTriples(RDFXML,     parserFactory) ;
        registerLangTriples(NTRIPLES,   parserFactory) ;
        registerLangTriples(N3,         parserFactory) ;
        registerLangTriples(TURTLE,     parserFactory) ;
        registerLangTriples(JSONLD,     parserFactoryJsonLD) ;
        registerLangTriples(RDFJSON,    parserFactory) ;
        registerLangTriples(CSV,        parserFactory) ;
        registerLangTriples(THRIFT,     parserFactoryThrift) ;
        registerLangTriples(TRIX,       parserFactoryTriX) ;
        registerLangTriples(RDFNULL,    parserFactoryRDFNULL) ;
        
        registerLangQuads(JSONLD,       parserFactoryJsonLD) ;
        registerLangQuads(NQUADS,       parserFactory) ;
        registerLangQuads(TRIG,         parserFactory) ;
        registerLangQuads(THRIFT,       parserFactoryThrift) ;
        registerLangQuads(TRIX,         parserFactoryTriX) ;
        registerLangQuads(RDFNULL,      parserFactoryRDFNULL) ;
    }

    /** Register a language and it's parser factory.
     * To create a {@link Lang} object use {@link LangBuilder}.
     */
    private static void registerLang(Lang lang, ReaderRIOTFactory factory)
    {
        RDFLanguages.register(lang) ;
        langToParserFactory.put(lang, factory) ;
    }
    
    /** Register a language and it's parser factory.
     * To create a {@link Lang} object use {@link LangBuilder}.
     */
    public static void registerLangTriples(Lang lang, ReaderRIOTFactory factory)
    {
        langTriples.add(lang) ;
        registerLang(lang, factory) ;
    }
    
    /** Register a language and it's parser factory.
     * To create a {@link Lang} object use {@link LangBuilder}.
     */
    public static void registerLangQuads(Lang lang, ReaderRIOTFactory factory)
    {
        langQuads.add(lang) ;
        registerLang(lang, factory) ;
    }

    /** Remove registration */
    public static void removeRegistration(Lang lang)
    {
        RDFLanguages.unregister(lang) ;
        langToParserFactory.remove(lang) ;
    }
    
    /** Return the parser factory for the language, or null if not registered */
    public static ReaderRIOTFactory getFactory(Lang language)
    {
        return langToParserFactory.get(language) ;
    }

    /** return true if the language has a registered parser. */
    public static boolean isRegistered(Lang lang) { return langToParserFactory.containsKey(lang) ; }

    /** return true if the language is registered with the triples parser factories */
    public static boolean isTriples(Lang lang) { return langTriples.contains(lang) ; }
    
    /** return true if the language is registered with the quads parser factories */
    public static boolean isQuads(Lang lang)   { return langQuads.contains(lang) ; }

    // Parser factories
    
    private static class ReaderRIOTFactoryImpl implements ReaderRIOTFactory
    {
        @Override
        public ReaderRIOT create(Lang lang) {
            return new ReaderRIOTLang(lang) ;
        }
    }

    private static class ReaderRIOTLang implements ReaderRIOT
    {
        private final Lang lang ;
        private ErrorHandler errorHandler ; 
        private ParserProfile parserProfile = null ;

        ReaderRIOTLang(Lang lang) {
            this.lang = lang ;
            errorHandler = ErrorHandlerFactory.getDefaultErrorHandler() ;
        }

        @Override
        public void read(InputStream in, String baseURI, ContentType ct, StreamRDF output, Context context) {
            LangRIOT parser = RiotParsers.createParser(in, lang, baseURI, output) ;
            if ( parserProfile != null )
                parser.setProfile(parserProfile);
            if ( errorHandler != null )
                parser.getProfile().setHandler(errorHandler) ;
            parser.parse() ;
        }

        @Override
        public void read(Reader in, String baseURI, ContentType ct, StreamRDF output, Context context) {
            LangRIOT parser = RiotParsers.createParser(in, lang, baseURI, output) ;
            parser.getProfile().setHandler(errorHandler) ; 
            parser.parse() ;
        }

        @Override public ErrorHandler getErrorHandler()                     { return errorHandler ; }
        @Override public void setErrorHandler(ErrorHandler errorHandler)    { this.errorHandler = errorHandler ; }

        @Override public ParserProfile getParserProfile()                   { return parserProfile ; } 
        @Override public void setParserProfile(ParserProfile parserProfile) { 
            this.parserProfile = parserProfile ;
            this.errorHandler = parserProfile.getHandler() ;
        }
    }

    private static class ReaderRIOTFactoryJSONLD implements ReaderRIOTFactory {
        @Override
        public ReaderRIOT create(Lang language) {
            if ( !Lang.JSONLD.equals(language) )
                throw new InternalErrorException("Attempt to parse " + language + " as JSON-LD") ;
            return new JsonLDReader() ;
        }
    }
 
    private static class ReaderRIOTFactoryThrift implements ReaderRIOTFactory {
        @Override
        public ReaderRIOT create(Lang language) {
            return new ReaderRDFThrift() ;
        }}
    
    private static class ReaderRDFThrift implements ReaderRIOT {
        @Override
        public void read(InputStream in, String baseURI, ContentType ct, StreamRDF output, Context context) {
            BinRDF.inputStreamToStream(in, output) ;
        }

        @Override
        public void read(Reader reader, String baseURI, ContentType ct, StreamRDF output, Context context) {
            throw new RiotException("RDF Thrift : Reading binary data from a java.io.reader is not supported. Please use an InputStream") ;
        }

        @Override
        public ErrorHandler getErrorHandler() {
            return null ;
        }

        @Override
        public void setErrorHandler(ErrorHandler errorHandler) {}

        @Override
        public ParserProfile getParserProfile() {
            return null ;
        }

        @Override
        public void setParserProfile(ParserProfile profile) {}
        
    }

    private static class ReaderRIOTFactoryTriX implements ReaderRIOTFactory {
        @Override
        public ReaderRIOT create(Lang language) {
            return new ReaderTriX() ;
        }
    }

    private static class ReaderRIOTFactoryRDFNULL implements ReaderRIOTFactory {
        @Override
        public ReaderRIOT create(Lang language) {
            return new ReaderRDFNULL() ;
        }
    }
}