package org.jtheque.core.utils.file;

 /*

  * This file is part of JTheque.

  *

  * JTheque is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, either version 3 of the License.

  *

  * JTheque is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with JTheque.  If not, see <http://www.gnu.org/licenses/>.

  */

 import org.jdom.Document;

 import org.jdom.Element;

 import org.jdom.JDOMException;

 import org.jdom.input.SAXBuilder;

 import org.jdom.xpath.XPath;

 import java.io.Closeable;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.net.URLConnection;

 import java.util.Collection;

 /**

  * A reader for XML files.

  *

  * @author Baptiste Wicht

  */

 public final class XMLReader implements Closeable {

     private InputStream stream;

     private Document document;

     private static final String OPEN_ERROR = "Error opening the file";

     private static final String READING_ERROR = "Error reading the file";

     /**

      * Open the file a the URL.

      *

      * @param strUrl The URL of the XML file.

      * @throws XMLException If an error occurs during the open process.

      */

     public void openURL(String strUrl) throws XMLException {

         URL url;

         try {

             url = new URL(strUrl);

         } catch (MalformedURLException e) {

             throw new XMLException("Invalid URL", e);

         }

         openURL(url);

     }

     /**

      * Open the file a the URL.

      *

      * @param url The URL of the XML file.

      * @throws XMLException If an error occurs during the open process.

      */

     public void openURL(URL url) throws XMLException {

         try {

             URLConnection urlConnection = url.openConnection();

             urlConnection.setUseCaches(false);

             urlConnection.connect();

             stream = urlConnection.getInputStream();

             SAXBuilder sxb = new SAXBuilder("org.apache.xerces.parsers.SAXParser");

             try {

                 document = sxb.build(stream);

             } catch (JDOMException e) {

                 throw new XMLException(OPEN_ERROR, e);

             }

         } catch (IOException e) {

             throw new XMLException(OPEN_ERROR, e);

         }

     }

     /**

      * Open the file.

      *

      * @param strFile The path to the file to open.

      * @throws XMLException If an error occurs during the open process.

      */

     public void openFile(String strFile) throws XMLException {

         openFile(new File(strFile));

     }

     /**

      * Open the file.

      *

      * @param file The file to open.

      * @throws XMLException If an error occurs during the open process.

      */

     public void openFile(File file) throws XMLException {

         try {

             stream = new FileInputStream(file);

             SAXBuilder sxb = new SAXBuilder();

             document = sxb.build(stream);

         } catch (JDOMException e) {

             throw new XMLException(OPEN_ERROR, e);

         } catch (IOException e) {

             throw new XMLException(OPEN_ERROR, e);

         }

     }

     @Override

     public void close() throws IOException {

         if (stream != null) {

             stream.close();

         }

     }

     /**

      * Return the root element of the reader.

      *

      * @return the root element else null if the reader is not open.

      */

     public Element getRootElement() {

         if (document != null) {

             return document.getRootElement();

         }

         return null;

     }

     /**

      * Return all the nodes corresponding to the XPath request on the specified node.

      *

      * @param path The XPath request.

      * @param node The node to request in.

      * @return A List containing all elements corresponding to the request.

      * @throws XMLException If an errors occurs during the reading process.

      */

     public Collection<Element> getNodes(String path, Object node) throws XMLException {

         try {

             return XPath.newInstance(path).selectNodes(node);

         } catch (JDOMException e) {

             throw new XMLException("Error selecting nodes", e);

         }

     }

     /**

      * Return the unique node corresponding to the XPath request on the specified node.

      *

      * @param path The XPath request.

      * @param node The node to request in.

      * @return The unique node corresponding to the request else null if there is no node corresponding to the request.

      * @throws XMLException If an errors occurs during the reading process.

      */

     public Element getNode(String path, Object node) throws XMLException {

         Element n;

         try {

             n = (Element) XPath.newInstance(path).selectSingleNode(node);

         } catch (JDOMException e) {

             throw new XMLException("Error selecting nodes", e);

         }

         return n;

     }

     /**

      * Indicate if a node exists with the specified path in the specified node.

      *

      * @param path The path to search for.

      * @param node The node to search from.

      *

      * @return true if the path exists from the node else false.

      *

      * @throws XMLException If an errors occurs during the reading process.

      */

     public boolean existsNode(String path, Object node) throws XMLException {

         return getNode(path, node) != null;

     }

     /**

      * Indicate if a value exists with the specified path in the specified node.

      *

      * @param path The path to search for.

      * @param node The node to search from.

      *

      * @return true if the path exists from the node else false.

      *

      * @throws XMLException If an errors occurs during the reading process.

      */

     public boolean existsValue(String path, Object node) throws XMLException {

         return readString(path, node) != null;

     }

     /**

      * Read a String value from the node.

      *

      * @param path The XPath request.

      * @param node The node.

      * @return The string value of the request.

      * @throws XMLException If an errors occurs during the reading process.

      */

     public String readString(String path, Object node) throws XMLException {

         String value;

         try {

             value = XPath.newInstance(path).valueOf(node);

         } catch (JDOMException e) {

             throw new XMLException(READING_ERROR, e);

         }

         return value;

     }

     /**

      * Read a int value from the node.

      *

      * @param path The XPath request.

      * @param node The node.

      * @return The int value of the request.

      * @throws XMLException If an errors occurs during the reading process.

      */

     public int readInt(String path, Object node) throws XMLException {

         String value;

         try {

             value = XPath.newInstance(path).valueOf(node);

         } catch (JDOMException e) {

             throw new XMLException(READING_ERROR, e);

         }

         return Integer.parseInt(value);

     }

     /**

      * Read a double value from the node.

      *

      * @param path The XPath request.

      * @param node The node.

      * @return The double value of the request.

      * @throws XMLException If an errors occurs during the reading process.

      */

     public double readDouble(String path, Object node) throws XMLException {

         String value;

         try {

             value = XPath.newInstance(path).valueOf(node);

         } catch (JDOMException e) {

             throw new XMLException(READING_ERROR, e);

         }

         return Double.parseDouble(value);

     }

     /**

      * Read a boolean value from the node.

      *

      * @param path The XPath request.

      * @param node The node.

      * @return The boolean value of the request.

      * @throws XMLException If an errors occurs during the reading process.

      */

     public boolean readBoolean(String path, Object node) throws XMLException {

         String value;

         try {

             value = XPath.newInstance(path).valueOf(node);

         } catch (JDOMException e) {

             throw new XMLException(READING_ERROR, e);

         }

         return Boolean.parseBoolean(value);

     }

     /**

      * Read a long value from the node.

      *

      * @param path The XPath request.

      * @param node The node.

      * @return The double value of the request.

      * @throws XMLException If an errors occurs during the reading process.

      */

     public long readLong(String path, Object node) throws XMLException {

         String value;

         try {

             value = XPath.newInstance(path).valueOf(node);

         } catch (JDOMException e) {

             throw new XMLException(READING_ERROR, e);

         }

         return Long.parseLong(value);

     }

 }