org.apache.jena.riot.thrift.TRDF.java Source code

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Here is the source code for org.apache.jena.riot.thrift.TRDF.java

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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.thrift;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.jena.atlas.io.IO;
import org.apache.jena.atlas.logging.Log;
import org.apache.jena.riot.RiotException;
import org.apache.jena.riot.system.StreamRDF;
import org.apache.jena.riot.thrift.wire.RDF_ANY;
import org.apache.jena.riot.thrift.wire.RDF_StreamRow;
import org.apache.jena.riot.thrift.wire.RDF_Term;
import org.apache.jena.riot.thrift.wire.RDF_UNDEF;
import org.apache.thrift.TException;
import org.apache.thrift.protocol.TCompactProtocol;
import org.apache.thrift.protocol.TJSONProtocol;
import org.apache.thrift.protocol.TProtocol;
import org.apache.thrift.protocol.TTupleProtocol;
import org.apache.thrift.transport.TIOStreamTransport;
import org.apache.thrift.transport.TTransport;

/** Support operations for RDF Thrift */
public class TRDF {
    public static final int InputBufferSize = 128 * 1024;
    public static final int OutputBufferSize = 128 * 1024;

    /**
     * Create Thrift protocol for the InputStream.
     * @param in InputStream
     */
    public static TProtocol protocol(InputStream in) {
        try {
            if (!(in instanceof BufferedInputStream))
                in = new BufferedInputStream(in, InputBufferSize);
            TTransport transport = new TIOStreamTransport(in);
            transport.open();
            TProtocol protocol = protocol(transport);
            return protocol;
        } catch (TException ex) {
            TRDF.exception(ex);
            return null;
        }
    }

    /**
     * Create Thrift protocol for the OutputStream.
     * The caller must call {@link TRDF#flush(TProtocol)} 
     * which will flush the underlying (internally buffered) output stream. 
     * @param out OutputStream
     */
    public static TProtocol protocol(OutputStream out) {
        try {
            // Flushing the protocol will flush the BufferedOutputStream 
            if (!(out instanceof BufferedOutputStream))
                out = new BufferedOutputStream(out, OutputBufferSize);
            TTransport transport = new TIOStreamTransport(out);
            transport.open();
            TProtocol protocol = protocol(transport);
            return protocol;
        } catch (TException ex) {
            TRDF.exception(ex);
            return null;
        }
    }

    /**
     * Decode the contents of the input stream and send to the {@link StreamRDF}.
     * @param filename
     */
    public static TProtocol protocol(String filename) {
        InputStream in = IO.openFile(filename);
        TProtocol protocol = protocol(in);
        return protocol;
    }

    public static TProtocol protocol(TTransport transport) {
        if (true)
            return new TCompactProtocol(transport);

        // Keep the warnings down.
        if (false)
            return new TTupleProtocol(transport);
        if (false)
            return new TJSONProtocol(transport);
        throw new RiotThriftException("No protocol impl choosen");
    }

    /** Flush a TProtocol; exceptions converted to {@link RiotException} */
    public static void flush(TProtocol protocol) {
        flush(protocol.getTransport());
    }

    /** Flush a TTransport; exceptions converted to {@link RiotException} */
    public static void flush(TTransport transport) {
        try {
            transport.flush();
        } catch (TException ex) {
            TRDF.exception(ex);
        }
    }

    public static final RDF_ANY ANY = new RDF_ANY();
    /** The Thrift RDF Term 'ANY' */
    public static final RDF_Term tANY = new RDF_Term();
    /** The Thrift RDF Term 'UNDEF' */
    public static final RDF_UNDEF UNDEF = new RDF_UNDEF();
    public static final RDF_Term tUNDEF = new RDF_Term();

    static {
        tANY.setAny(new RDF_ANY());
    }

    static {
        tUNDEF.setUndefined(new RDF_UNDEF());
    }

    public static void visit(RDF_StreamRow row, VisitorStreamRowTRDF visitor) {
        if (row.isSetTriple()) {
            visitor.visit(row.getTriple());
        } else if (row.isSetQuad()) {
            visitor.visit(row.getQuad());
        } else if (row.isSetPrefixDecl()) {
            visitor.visit(row.getPrefixDecl());
        } else {
            Log.warn(ThriftConvert.class, "visit: Unrecognized: " + row);
        }
    }

    public static void exception(TException ex) {
        throw new RiotThriftException(ex);
    }

}