// SAX default implementation for Locator.
// No warranty; no copyright -- use this as you will.
// $Id: LocatorImpl.java,v 1.2 1998/04/27 01:48:00 david Exp $

package org.xml.sax.helpers;

import org.xml.sax.Locator;


/**
  * Provide an optional convenience implementation of Locator.
  *
  * <p>This class is available mainly for application writers, who
  * can use it to make a persistent snapshot of a locator at any
  * point during a document parse:</p>
  *
  * <pre>
  * Locator locator;
  * Locator startloc;
  *
  * public void setLocator (Locator locator)
  * {
  *         // note the locator
  *   this.locator = locator;
  * }
  *
  * public void startDocument ()
  * {
  *         // save the location of the start of the document
  *         // for future use.
  *   Locator startloc = new LocatorImpl(locator);
  * }
  *</pre>
  *
  * <p>Normally, parser writers will not use this class, since it
  * is more efficient to provide location information only when
  * requested, rather than constantly updating a Locator object.</p>
  *
  * @see org.xml.sax.Locator
  */
public class LocatorImpl implements Locator
{


  /**
    * Zero-argument constructor.
    *
    * <p>This will not normally be useful, since the main purpose
    * of this class is to make a snapshot of an existing Locator.</p>
    */
  public LocatorImpl ()
  {
  }


  /**
    * Copy constructor.
    *
    * <p>Create a persistent copy of the current state of a locator.
    * When the original locator changes, this copy will still keep
    * the original values (and it can be used outside the scope of
    * DocumentHandler methods).</p>
    *
    * @param locator The locator to copy.
    */
  public LocatorImpl (Locator locator)
  {
    setPublicId(locator.getPublicId());
    setSystemId(locator.getSystemId());
    setLineNumber(locator.getLineNumber());
    setColumnNumber(locator.getColumnNumber());
  }



  //////////////////////////////////////////////////////////////////////
  // Implementation of org.xml.sax.Locator
  //////////////////////////////////////////////////////////////////////


  /**
    * Return the saved public identifier.
    *
    * @return The public identifier as a string, or null if none
    *         is available.
    * @see org.xml.sax.Locator#getPublicId
    * @see #setPublicId
    */
  public String getPublicId ()
  {
    return publicId;
  }


  /**
    * Return the saved system identifier.
    *
    * @return The system identifier as a string, or null if none
    *         is available.
    * @see org.xml.sax.Locator#getSystemId
    * @see #setSystemId
    */
  public String getSystemId ()
  {
    return systemId;
  }


  /**
    * Return the saved line number (1-based).
    *
    * @return The line number as an integer, or -1 if none is available.
    * @see org.xml.sax.Locator#getLineNumber
    * @see #setLineNumber
    */
  public int getLineNumber ()
  {
    return lineNumber;
  }


  /**
    * Return the saved column number (1-based).
    *
    * @return The column number as an integer, or -1 if none is available.
    * @see org.xml.sax.Locator#getColumnNumber
    * @see #setColumnNumber
    */
  public int getColumnNumber ()
  {
    return columnNumber;
  }



  //////////////////////////////////////////////////////////////////////
  // Setters for the properties (not in org.xml.sax.Locator)
  //////////////////////////////////////////////////////////////////////


  /**
    * Set the public identifier for this locator.
    *
    * @param publicId The new public identifier, or null 
    *        if none is available.
    * @see #getPublicId
    */
  public void setPublicId (String publicId)
  {
    this.publicId = publicId;
  }


  /**
    * Set the system identifier for this locator.
    *
    * @param systemId The new system identifier, or null 
    *        if none is available.
    * @see #getSystemId
    */
  public void setSystemId (String systemId)
  {
    this.systemId = systemId;
  }


  /**
    * Set the line number for this locator (1-based).
    *
    * @param lineNumber The line number, or -1 if none is available.
    * @see #getLineNumber
    */
  public void setLineNumber (int lineNumber)
  {
    this.lineNumber = lineNumber;
  }


  /**
    * Set the column number for this locator (1-based).
    *
    * @param columnNumber The column number, or -1 if none is available.
    * @see #getColumnNumber
    */
  public void setColumnNumber (int columnNumber)
  {
    this.columnNumber = columnNumber;
  }



  //////////////////////////////////////////////////////////////////////
  // Internal state.
  //////////////////////////////////////////////////////////////////////

  private String publicId;
  private String systemId;
  private int lineNumber;
  private int columnNumber;

}