content: /*
   * Copyright (c) 2013-2014 3 Round Stones Inc., Some Rights Reserved
   *
   * 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 org.callimachusproject.xml;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.net.URI;
  import java.util.ArrayList;
  import java.util.Map;
  
  import net.sf.saxon.Configuration;
  import net.sf.saxon.query.StaticQueryContext;
  import net.sf.saxon.s9api.ItemType;
  import net.sf.saxon.s9api.Processor;
  import net.sf.saxon.s9api.QName;
  import net.sf.saxon.s9api.SaxonApiException;
  import net.sf.saxon.s9api.Serializer;
  import net.sf.saxon.s9api.XQueryCompiler;
  import net.sf.saxon.s9api.XQueryEvaluator;
  import net.sf.saxon.s9api.XQueryExecutable;
  import net.sf.saxon.s9api.XdmAtomicValue;
  import net.sf.saxon.s9api.XdmItem;
  import net.sf.saxon.s9api.XdmValue;
  import net.sf.saxon.trans.XPathException;
  
  import org.openrdf.http.object.client.HttpUriClient;
  import org.openrdf.http.object.io.ProducerStream;
  import org.openrdf.http.object.io.ProducerStream.OutputProducer;
  import org.xml.sax.SAXException;
  
  public class XQueryEngine {
  	private static final String XQUERY_MEDIA = "application/xquery, application/xml, application/xslt+xml, text/xml, text/xsl";
  	private final String baseURI;
  	private final HttpUriClient client;
  	private final ErrorListListener messages = new ErrorListListener();
  
  	public XQueryEngine(String baseURI, HttpUriClient client) {
  		this.baseURI = baseURI;
  		this.client = client;
  	}
  
  	public void validate(InputStream queryStream) throws IOException {
  		Configuration config = Configuration.newConfiguration();
          StaticQueryContext staticEnv = config.newStaticQueryContext();
          staticEnv.setBaseURI(baseURI);
          staticEnv.setErrorListener(messages);
          staticEnv.setModuleURIResolver(new InputSourceResolver(XQUERY_MEDIA, client));
          try {
  			staticEnv.compileQuery(queryStream, null);
  		} catch (XPathException e) {
  			messages.fatalError(e);
  		}
  	}
  
  	public String[] getErrorMessages() {
  		return messages.getErrorMessages();
  	}
  
  	public InputStream evaluateResult(InputStream queryStream,
  			Map<String, String[]> parameters) throws IOException,
  			SaxonApiException, SAXException {
  		return evaluateResult(queryStream, parameters, null, null);
  	}
  
  	public InputStream evaluateResult(InputStream queryStream,
  			Map<String, String[]> parameters, InputStream documentStream,
  			String documentId) throws IOException, SaxonApiException, SAXException {
  		final Processor qtproc = new Processor(false);
  		XdmNodeFactory resolver = new XdmNodeFactory(qtproc, client);
  		XQueryCompiler xqcomp = qtproc.newXQueryCompiler();
  		xqcomp.setBaseURI(URI.create(baseURI));
  		xqcomp.setModuleURIResolver(resolver);
  		XQueryExecutable xqexec = xqcomp.compile(queryStream);
  		final XQueryEvaluator xqeval = xqexec.load();
  		xqeval.setURIResolver(resolver);
  		if (parameters != null) {
  			for (Map.Entry<String, String[]> e : parameters.entrySet()) {
  				QName name = new QName(e.getKey());
  				ArrayList<XdmItem> values = new ArrayList<XdmItem>(e.getValue().length);
  				for (String value : e.getValue()) {
  					values.add(new XdmAtomicValue(value, ItemType.STRING));
  				}
  				xqeval.setExternalVariable(name, new XdmValue(values));
  			}
  		}
  		if (documentStream != null) {
  			xqeval.setContextItem(resolver.parse(documentId, documentStream));
  		}
  		return new ProducerStream(new OutputProducer() {
  			public void produce(OutputStream out) throws IOException {
  				xqeval.setDestination(qtproc.newSerializer(out));
  				try {
  					xqeval.run();
  				} catch (SaxonApiException e) {
  					throw new IOException(e);
  				}
  			}
  		});
  	}
  }
  