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GATE - general achitecture for text engineering - is open source software capable of solving almost any text processing problem. This artifact enables you to embed the core GATE Embedded with its essential dependencies. You will able to use the GATE Embedded API and load and store GATE XML documents. This artifact is the perfect dependency for CREOLE plugins or for applications that need to customize the GATE dependencies due to confict with their own dependencies or for lower footprint.

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/*
 *  ObjectWrapper.java
 *
 *  Copyright (c) 1995-2012, The University of Sheffield. See the file
 *  COPYRIGHT.txt in the software or at http://gate.ac.uk/gate/COPYRIGHT.txt
 *
 *  This file is part of GATE (see http://gate.ac.uk/), and is free
 *  software, licenced under the GNU Library General Public License,
 *  Version 2, June 1991 (in the distribution as file licence.html,
 *  and also available at http://gate.ac.uk/gate/licence.html).
 *
 *  Valentin Tablan, 8 Mar 2012
 *
 *  $Id: ObjectWrapper.java 19658 2016-10-10 06:46:13Z markagreenwood $
 */
package gate.corpora;

import java.io.StringWriter;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.thoughtworks.xstream.XStream;

import gate.Gate;
import gate.util.xml.XML11StaxDriver;

/**
 * Class used to wrap arbitrary values prior to saving as GATE XML. The 
 * {@link #toString()} method uses {@link XStream} to serialise the 
 * ObjectWrapper as XML; while the {@link #ObjectWrapper(String)} constructor
 * performs the reverse, parsing the previously saved XML and re-creating the 
 * wrapped value. 
 */
public class ObjectWrapper {
  
  /**
   * The value being wrapped. 
   */
  protected Object value;
  
  private static final XStream xstream;

  static {
	  /**
	   * Use XML 1.1 in case the XML representation includes characters
	   * that 1.0 forbids (typically control characters).
	   */
	  xstream = new XStream(new XML11StaxDriver());
	  Gate.configureXStreamSecurity(xstream);
  }

  protected static final Logger log = LoggerFactory.getLogger(ObjectWrapper.class);

  /**
   * Wraps an arbitrary value, which must be serialisable by XStream.
   * @param value any of any class that can be XML-serialised by XStream.
   */
  public ObjectWrapper(Object value) {
    this.value = value;
  }

  /**
   * De-serialises an {@link ObjectWrapper} instance from a string previously 
   * obtained by calling {@link #toString()}.
   * @param xmlSerialisation the XML string representing the saved 
   * {@link ObjectWrapper} instance.
   */
  public ObjectWrapper(String xmlSerialisation) {
    Object other = xstream.fromXML(xmlSerialisation);
    if(other instanceof ObjectWrapper) {
      this.value = ((ObjectWrapper)other).value;
    } else {
      log.error("Value de-serialised from XML is of type \"" + 
          other.getClass().getName() + "\", instead of expected \"" + 
          ObjectWrapper.class.getName() + ". Value was lost.");
      value = null;
    }
  }

  /**
   * Produces an XML serialisation of this {@link ObjectWrapper} instance, that
   * can be deserialised by using the {@link #ObjectWrapper(String)} constructor.
   * @see java.lang.Object#toString()
   */
  @Override
  public String toString() {
    StringWriter out  = new StringWriter();
    xstream.toXML(this, out);
    return out.toString();
  }

  /**
   * Gets the wrapped value.
   * 
   * @return the value
   */
  public Object getValue() {
    return value;
  }
}