/**
 * Redistribution and use of this software and associated documentation ("Software"), with or
 * without modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions
 * must also contain a copy of this document.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided with
 * the distribution.
 *
 * 3. The name "Exolab" must not be used to endorse or promote products derived from this Software
 * without prior written permission of Intalio, Inc. For written permission, please contact
 * info@exolab.org.
 *
 * 4. Products derived from this Software may not be called "Exolab" nor may "Exolab" appear in
 * their names without prior written permission of Intalio, Inc. Exolab is a registered trademark of
 * Intalio, Inc.
 *
 * 5. Due credit should be given to the Exolab Project (http://www.exolab.org/).
 *
 * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTALIO, INC. OR ITS
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright 2002 (C) Intalio, Inc. All Rights Reserved.
 *
 * $Id$
 */
package org.exolab.castor.xml.schema.reader;

import java.io.Reader;

import org.exolab.castor.net.URILocation;
import org.exolab.castor.net.util.URIUtils;
import org.exolab.castor.xml.schema.Schema;


/**
 * An implementation of URILocation for applications that need to resolve an XML Schema in a
 * non-standard way, such as a Schema embedded in another XML document, or a Schema created
 * in-memory, etc.
 *
 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
 * @version $Revision$ $Date: 2006-04-25 15:08:23 -0600 (Tue, 25 Apr 2006) $
 */
public final class SchemaLocation extends URILocation {

  private String _documentBase = null;
  private String _absoluteURI = null;
  private String _relativeURI = null;


  /**
   * A reference to an alread loaded schema
   */
  private Schema _schema = null;


  /**
   * Creates a new SchemaLocation
   *
   * @param schema the Schema that represents the resource at identified by this URILocation
   * @param href the absolute URL for the resource identified by this URILocation.
   */
  public SchemaLocation(Schema schema, String href) {
    if (schema == null)
      throw new IllegalStateException("argument 'schema' must not be null.");

    _schema = schema;

    if (href != null) {
      _absoluteURI = URIUtils.resolveAsString(href, null);
    }
  } // -- SchemaLocation

  /**
   * Returns the absolute URI for this URILocation
   *
   * @return the absolute URI for this URILocation
   * @see #getRelativeURI
   * @see #getBaseURI
   **/
  public String getAbsoluteURI() {
    return _absoluteURI;
  } // -- getAbsoluteURI

  /**
   * Returns the base location of this URILocation. If this URILocation is an URL, the base location
   * will be equivalent to the document base for the URL.
   *
   * @return the base location of this URILocation
   * @see #getAbsoluteURI
   * @see #getRelativeURI
   **/
  public String getBaseURI() {
    if (_documentBase == null) {
      if (_absoluteURI != null) {
        _documentBase = URIUtils.getDocumentBase(_absoluteURI);
      }
    }
    return _documentBase;
  } // -- getBaseURI

  /**
   * Returns a Reader for the resource represented by this URILocation.
   *
   * Note: This method always returns null for this URILocation
   *
   * @return a Reader for the resource represented by this URILocation
   * @exception java.io.FileNotFoundException
   * @exception java.io.IOException
   **/
  public Reader getReader() throws java.io.IOException {
    return null; // -- Not Supported by this URILocation
  } // -- getReader

  /**
   * Returns the relative URI for this URILocation
   *
   * @return the relative URI for this URILocation
   * @see #getAbsoluteURI
   * @see #getBaseURI
   **/
  public String getRelativeURI() {

    if (_relativeURI == null) {
      if (_absoluteURI != null) {
        int idx = getBaseURI().length();
        _relativeURI = _absoluteURI.substring(idx);
      }
    }

    return _relativeURI;

  } // -- getRelativeURI

  /**
   * Returns the Schema for this SchemaLocation, or null if this SchemaLocation was not constructed
   * with a Schema object.
   *
   * @return the Schema for this SchemaLocation, or null if no Schema object was set.
   */
  public Schema getSchema() {
    return _schema;
  } // -- getSchema

  /**
   * Returns the String representation of this URILocation.
   *
   * @return the String representation of this URILocation
   **/
  public String toString() {
    if (_absoluteURI != null)
      return _absoluteURI;
    return "URILocation: " + _schema.toString();
  }

} // -- SchemaLocation
