/**
* Show how to run two queries in tandem. The second query is applied to the results of the first.
*/
public static void examplePipeline() throws XPathException {
final Configuration config = new Configuration();
// Compile the first query
final StaticQueryContext sqc1 = config.newStaticQueryContext();
final XQueryExpression exp1 =
sqc1.compileQuery(
"declare variable $in as xs:integer external;" + "document{ <a>{$in * $in}</a> }");
// Compile the second query (each query should have its own static context)
final StaticQueryContext sqc2 = config.newStaticQueryContext();
final XQueryExpression exp2 = sqc2.compileQuery("/a + 5");
// Run the first query
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
dynamicContext.setParameterValue("in", Int64Value.makeIntegerValue(3));
final NodeInfo doc = (NodeInfo) exp1.evaluateSingle(dynamicContext);
// Run the second query
dynamicContext.clearParameters();
dynamicContext.setContextItem(doc);
final Object result = exp2.evaluateSingle(dynamicContext);
System.out.println("3*3 + 5 = " + result);
// The result is actually a java.lang.Double
}
/**
* Show a query producing a single atomic value as its result and returning the value to the Java
* application
*/
public static void exampleToSingleton() throws XPathException {
final Configuration config = new Configuration();
final StaticQueryContext sqc = config.newStaticQueryContext();
final XQueryExpression exp = sqc.compileQuery("avg(for $i in 1 to 10 return $i*$i)");
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
final BigDecimal result = (BigDecimal) exp.evaluateSingle(dynamicContext);
System.out.println(result);
}
/**
* Show a query that takes a parameter (external variable) as input. The query produces a single
* atomic value as its result and returns the value to the Java application. For the types of
* value that may be returned, and their mapping to XPath data types, see {@link
* XPathEvaluator#evaluate}
*/
public static void exampleWithParam() throws XPathException {
final Configuration config = new Configuration();
final StaticQueryContext sqc = config.newStaticQueryContext();
final XQueryExpression exp =
sqc.compileQuery("declare variable $in as xs:integer external;" + "$in * $in");
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
dynamicContext.setParameterValue("in", Int64Value.makeIntegerValue(17));
final Long result = (Long) exp.evaluateSingle(dynamicContext);
System.out.println("17 * 17 = " + result);
}
/**
* Show how to run a query that is read from a file and that serializes its output as HTML to
* another file. The input to the query (the initial value of the context node) is supplied as the
* content of another file.
*/
public static void exampleToHTMLFile() throws XPathException, IOException {
final Configuration config = new Configuration();
final StaticQueryContext sqc = config.newStaticQueryContext();
final XQueryExpression exp = sqc.compileQuery(new FileReader("query/books-to-html.xq"));
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
dynamicContext.setContextItem(config.buildDocument(new StreamSource("data/books.xml")));
final Properties props = new Properties();
props.setProperty(OutputKeys.METHOD, "html");
props.setProperty(OutputKeys.DOCTYPE_PUBLIC, "-//W3C//DTD HTML 4.01 Transitional//EN");
exp.run(dynamicContext, new StreamResult(new File("booklist.html")), props);
}
/** Show a query producing a document as its result and serializing this directly to System.out */
public static void exampleToStreamResult() throws XPathException {
final Configuration config = new Configuration();
final StaticQueryContext sqc = config.newStaticQueryContext();
final XQueryExpression exp = sqc.compileQuery("<a b='c'>{5+2}</a>");
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
final Properties props = new Properties();
props.setProperty(OutputKeys.METHOD, "xml");
props.setProperty(OutputKeys.INDENT, "yes");
exp.run(dynamicContext, new StreamResult(System.out), props);
}
/**
* Show a query producing a sequence as its result and returning the sequence to the Java
* application in the form of an iterator. The sequence is treated as if it were the content of a
* document{...} constructor. Note that it must not contain free-standing attribute nodes.
*/
public static void exampleToSerializedSequence() throws XPathException {
final Configuration config = new Configuration();
final StaticQueryContext sqc = config.newStaticQueryContext();
final XQueryExpression exp =
sqc.compileQuery("<doc><chap><a>3</a></chap></doc>//a, <b>4</b>, 19");
Properties props = new Properties();
props.setProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
final SequenceIterator iter = exp.iterator(dynamicContext);
QueryResult.serializeSequence(iter, config, System.out, props);
}
/**
* Show a query producing a sequence as its result and returning the sequence to the Java
* application in the form of an iterator. The sequence is then output by wrapping the items in a
* document, with wrapping elements indicating the type of each item, and serializing the
* resulting document.
*/
public static void exampleToWrappedSequence() throws XPathException {
final Configuration config = new Configuration();
final StaticQueryContext sqc = config.newStaticQueryContext();
final XQueryExpression exp =
sqc.compileQuery("<doc><chap><a>3</a></chap></doc>//a, <b>4</b>, attribute c {5}, 19");
Properties props = new Properties();
props.setProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
props.setProperty(OutputKeys.INDENT, "yes");
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
final SequenceIterator iter = exp.iterator(dynamicContext);
final DocumentInfo doc = QueryResult.wrap(iter, config);
QueryResult.serialize(doc, new StreamResult(System.out), props);
}
/**
* Show a query producing a sequence as its result and returning the sequence to the Java
* application in the form of an iterator. For each item in the result, its string value is
* output.
*/
public static void exampleToSequence() throws XPathException {
final Configuration config = new Configuration();
final StaticQueryContext sqc = config.newStaticQueryContext();
final XQueryExpression exp = sqc.compileQuery("for $i in 1 to 10 return ($i * $i)");
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
final SequenceIterator iter = exp.iterator(dynamicContext);
while (true) {
Item item = iter.next();
if (item == null) {
break;
}
System.out.println(item.getStringValue());
}
}
/**
* Show a query producing a DOM as its output. The DOM is then serialized using an identity
* transform
*/
public static void exampleToDOM() throws TransformerException {
final Configuration config = new Configuration();
final StaticQueryContext sqc = config.newStaticQueryContext();
final XQueryExpression exp =
sqc.compileQuery("<a xmlns='http://a/uri' xmlns:a='another.uri'>text</a>");
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
DOMResult result = new DOMResult();
exp.run(dynamicContext, result, new Properties());
// now serialize the DOM
Transformer identity = TransformerFactory.newInstance().newTransformer();
identity.transform(new DOMSource(result.getNode()), new StreamResult(System.out));
}
/**
* Show a direct call from the Java application to a function defined in the Query. This is a very
* efficient way of invoking a query, but it does minimal checking of the supplied arguments
*/
public static void exampleDirectFunction() throws XPathException {
final Configuration config = new Configuration();
final StaticQueryContext sqc = config.newStaticQueryContext();
final XQueryExpression exp1 =
sqc.compileQuery(
"declare namespace f='f.ns';"
+ "declare function f:t1($v1 as xs:integer, $v2 as xs:untypedAtomic*) { "
+ " $v1 div $v2"
+ "};"
+ "10");
final UserFunction fn1 = exp1.getStaticContext().getUserDefinedFunction("f.ns", "t1", 2);
if (fn1 == null) {
throw new IllegalStateException("Function f:t1() not found");
}
final Controller controller = exp1.newController();
final Value[] arglist = new Value[2];
arglist[0] = new Int64Value(10);
for (int i = 3; i < 10; i++) {
arglist[1] = new Int64Value(i);
final ValueRepresentation result = fn1.call(arglist, controller);
System.out.println(arglist[0] + " div " + arglist[1] + " = " + result);
}
}
