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1   package ca.uhn.fhir.util;
2   
3   /*-
4    * #%L
5    * HAPI FHIR - Core Library
6    * %%
7    * Copyright (C) 2014 - 2019 University Health Network
8    * %%
9    * Licensed under the Apache License, Version 2.0 (the "License");
10   * you may not use this file except in compliance with the License.
11   * You may obtain a copy of the License at
12   * 
13   *      http://www.apache.org/licenses/LICENSE-2.0
14   * 
15   * Unless required by applicable law or agreed to in writing, software
16   * distributed under the License is distributed on an "AS IS" BASIS,
17   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18   * See the License for the specific language governing permissions and
19   * limitations under the License.
20   * #L%
21   */
22  
23  import org.slf4j.Logger;
24  import org.slf4j.LoggerFactory;
25  
26  import java.io.Reader;
27  import java.io.StringReader;
28  
29  public class XmlDetectionUtil {
30  
31  	private static final Logger ourLog = LoggerFactory.getLogger(XmlDetectionUtil.class);
32  	private static Boolean ourStaxPresent;
33  
34  	/**
35  	 * This method will return <code>true</code> if a StAX XML parsing library is present
36  	 * on the classpath
37  	 */
38  	public static boolean isStaxPresent() {
39  		Boolean retVal = ourStaxPresent;
40  		if (retVal == null) {
41  			try {
42  				Class.forName("javax.xml.stream.events.XMLEvent");
43  				Class<?> xmlUtilClazz = Class.forName("ca.uhn.fhir.util.XmlUtil");
44  				xmlUtilClazz.getMethod("createXmlReader", Reader.class).invoke(xmlUtilClazz, new StringReader(""));
45  				ourStaxPresent = Boolean.TRUE;
46  				retVal = Boolean.TRUE;
47  			} catch (Throwable t) {
48  				ourLog.info("StAX not detected on classpath, XML processing will be disabled");
49  				ourStaxPresent = Boolean.FALSE;
50  				retVal = Boolean.FALSE;
51  			}
52  		}
53  		return retVal;
54  	}
55  
56  	
57  }