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Basics3 is a collection of Java classes used by the YAGO project.
There is a newer version: 1.1
package basics;

import java.io.File;
import java.io.IOException;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;

import javatools.filehandlers.FileSet;
import javatools.filehandlers.FileUtils;

/**
Copyright 2016 Fabian M. Suchanek

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.

This class writes YAGO facts into a Turtle-compatible output format.
Output validates with http://www.rdfabout.com/demo/validator
 */
public class N4Writer extends FactWriter {

  /** Writes the file */
  protected Writer writer;

  /** Starts a writer to this file */
  public N4Writer(File f, String header, String base, Map prefixes) throws Exception {
    super(f);
    writer = FileUtils.getBufferedUTF8Writer(f);
    if (header != null) {
      for (String line : header.split("\n")) {
        writer.write("# " + line + "\n");
      }
    }
    writer.write("\n@base <" + base + "> .\n");
    for (String prefix : FactComponent.standardPrefixes.keySet()) {
      writer.write("@prefix " + prefix + " <" + FactComponent.standardPrefixes.get(prefix) + "> .\n");
    }
    if (prefixes != null) for (Map.Entry prefix : prefixes.entrySet()) {
      writer.write("@prefix " + prefix.getKey() + " <" + FactComponent.standardPrefixes.get(prefix.getValue()) + "> .\n");
    }
    writer.write("\n");
    if (header != null) {
      header = header.replaceAll("\\s+", " ");
      Fact comment = new Fact(FactComponent.forYagoEntity("yagoTheme_" + FileSet.newExtension(f.getName(), null)), YAGO.hasGloss,
          FactComponent.forString(header));
      write(comment);
    }
  }

  /** Starts a writer to this file */
  public N4Writer(File f, String header) throws Exception {
    this(f, header, "http://yago-knowledge.org/resource/", new HashMap());
  }

  /** Writes a fact */
  @Override
  public synchronized void write(Fact f) throws IOException {
    if (f.getId() != null) writer.write("#@ " + f.getId() + "\n");
    writer.write(f.subject);
    writer.write("\t");
    writer.write(f.relation);
    writer.write("\t");
    writer.write(f.object);
    writer.write(" .\n");
  }

  @Override
  public void close() throws IOException {
    writer.close();
  }

  @Override
  public void flush() throws IOException {
    writer.flush();
  }

  /** Test*/
  public static void main(String[] args) throws Exception {
    try (FactWriter w = new N4Writer(new File("c:/fabian/temp/t.ttl"), "Blah blah \n   \t blub \t blah")) {
      w.write(new Fact("", "rdf:type", ""));
    }

  }

  @Override
  public void writeComment(String comment) throws IOException {
    writer.write("# ");
    writer.write(comment);
    writer.write("\n");
  }

}