/*   Copyright 2006 - 2009 ETH Zurich 
 *
 *   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.
 */

package examples;

import java.io.StringReader;

import ch.ethz.mxquery.query.XQCompiler;
import ch.ethz.mxquery.query.PreparedStatement;
import ch.ethz.mxquery.query.impl.CompilerImpl;
import ch.ethz.mxquery.contextConfig.CompilerOptions;
import ch.ethz.mxquery.contextConfig.Context;
import ch.ethz.mxquery.datamodel.QName;
import ch.ethz.mxquery.exceptions.MXQueryException;
import ch.ethz.mxquery.exceptions.QueryLocation;
import ch.ethz.mxquery.model.XDMIterator;
import ch.ethz.mxquery.xdmio.XDMInputFactory;
import ch.ethz.mxquery.xdmio.XDMSerializer;
import ch.ethz.mxquery.xdmio.XMLSource;

public class SimpleExample {

    public static void main(String[] args) throws Exception {
	// Sample query, replace by your own
	String query = "declare variable $input external; <result>{$input,$input}</result>";

	boolean updateFiles = true;

	// Create new (unified) Context
	Context ctx = new Context();
	// Create a compiler options oh
	CompilerOptions co = new CompilerOptions();
	// Enable schema support
	co.setSchemaAwareness(true);
	// Enable update facility support
	co.setUpdate(true);
	// use updateable stores by default
	ctx.getStores().setUseUpdateStores(true);
	ctx.getStores().setSerializeStores(updateFiles);
	// create a XQuery compiler
	XQCompiler compiler = new CompilerImpl();
	PreparedStatement statement;

	try {
	    // out of the context and the query "text" create a prepared
	    // statement,
	    // considering the compiler options
	    statement = compiler.compile(ctx, query, co);
	    XDMIterator result;
	    String strResult = "";
	    // Get an iterator from the prepared statement
	    // Set up dynamic context values, e.g., current time
	    result = statement.evaluate();
	    // Add the contents of the external variable
	    String xml = "<elem/>";
	    XMLSource xmlIt = XDMInputFactory.createXMLInput(result
		    .getContext(), new StringReader(xml), true,
		    Context.NO_VALIDATION, QueryLocation.OUTSIDE_QUERY_LOC);
	    statement.addExternalResource(new QName("input"), xmlIt);
	    // Create an XDM serializer, can take an XDMSerializerSettings
	    // object if needed
	    XDMSerializer ip = new XDMSerializer();
	    // run expression, generate XDM instance and serialize into String
	    // format
	    strResult = ip.eventsToXML(result);
	    // XQuery Update "programs" create a pending update list, not a
	    // normal result
	    // apply the results to the relevant "stores"
	    // currently in-memory stores
	    statement.applyPUL();
	    // serialize the contents of modified stores to disk
	    // in this case, do not make a backup of the modified files
	    if (updateFiles)
		statement.serializeStores(false);
	    // Release all resources associated with the statement
	    statement.close();

	    System.out.println(strResult);
	} catch (MXQueryException err) {
	    MXQueryException.printErrorPosition(query, err.getLocation());
	    System.err.println("Error:");
	    throw err;
	}

    }
}