Develop Reference

How to get SpringBoot to find my file in the src/main/resources directory

I have the following class (below). The file corresponding to vocabLookupFile is found when in the root directory of my SpringBoot project. However, I really want it in the src/main/resources directory of the project. With the below setup, it is not found there. By the way, the LookupMapper component is autowired in a #Service class, and other than not finding the file in src/main/resources, it works fine.
I am hoping someone can tell me how to modify the below so it can be found there. Thanks for any ideas.
#Component
public class LookupMapper {
public HashMap<String, LookUp> entry = new HashMap<>();
#Autowired
public LookupMapper(#Value("${vocab.lookup.mapper}") String vocabLookupFile) throws IOException {
try (CSVReader csvReader = new CSVReader(new FileReader(vocabLookupFile))) {
String[] values = null;
while ((values = csvReader.readNext()) != null) {
LookUp lookUp = new LookUp(values[1], Boolean.parseBoolean(values[2]));
this.entry.put(values[0].toUpperCase(), lookUp);
}
}
}
}

as per Mark Rotteveel, suggestion, with my file in the resource directory, in general, I need a solution that could retrieve the file from the context of the jar (and those things in the jar are considered "resources"). I used Classloader to get the resource as a stream. So the below works for me. Thanks to Mark.
#Component
public class LookupMapper {
public HashMap<String, LookUp> entry = new HashMap<>();
#Autowired
public LookupMapper(#Value("${vocab.lookup.mapper}") String vocabLookupFile) throws IOException {
ClassLoader classLoader = getClass().getClassLoader();
try (CSVReader csvReader = new CSVReader(new InputStreamReader(classLoader.getResourceAsStream(vocabLookupFile)))) {
String[] values = null;
while ((values = csvReader.readNext()) != null) {
LookUp lookUp = new LookUp(values[1], Boolean.parseBoolean(values[2]));
this.entry.put(values[0].toUpperCase(), lookUp);
}
}
}
}

How to load resources from within a jar file loaded in a java application?

So, I have a main application that should load a jar that contains code and other resources (i.e.: jar files, text files, java properties etc.). I use:
JarFile jar = new JarFile(jar);
Enumeration<JarEntry> entries = jar.entries();
int URLsize = 1;
while (entries.hasMoreElements())
if (entries.nextElement().getName().startsWith("foo/bar/foobar"))
URLsize++;
entries = jar.entries();
URL[] urls = new URL[URLsize];
urls[0] = patch.toURI().toURL();
int count = 1;
while (entries.hasMoreElements())
{
JarEntry nextElement = entries.nextElement();
if (nextElement.getName().startsWith("foo/bar/foobar"))
{
urls[count] = new URL("jar:file:/"+ jar.getAbsolutePath() + "!/" + nextElement.getName());
count++;
}
}
to load the resources of the jar, and an URLClassLoader plus some reflection to get all resources together and execute the jar's main class, like this:
URLClassLoader loader = new URLClassLoader (urls);
Thread.currentThread().setContextClassLoader(loader);
Class<?> jarC = Class.forName ("foo.bar.barfoo.Main", true, loader);
Constructor<?> cons = jarC.getConstructor(String.class, String.class, Properties.class, Properties.class, String[].class);
Object instance = cons.newInstance (systemPath, programPath, config, some_data, args);
Method method = jarC.getMethod ("Main");
method.invoke (instance);
Now the problem is that inside the loaded jar's code when I try to load a bunch of files (resources) from a package inside the jar (e.g.: /foo/bar/foobar) it throws a NullPointerException.
private static InputStream getResourceAsStream(String resource) {
try {
return Thread.currentThread().getContextClassLoader().getResource(resource).openStream();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
That's how I try to get the package that than gets parsed with a BufferedReader and an InputStreamReader to get the names of each resource inside the package.
Okay, maybe a bit too detailed (this is just one way I use the getResourceAsStream method), but I hope I made myself understood, the ContextClassLoader doesn't contain the resources I loaded in the application that runs this jar within itself, so what do I need to do to get those from within the loaded jar?
EDIT: Calling the getResourceAsStream method:
private static List<String> getResourceFiles(String path) throws IOException {
List<String> filenames = new ArrayList<>();
try (
InputStream in = getResourceAsStream(path);
BufferedReader br = new BufferedReader(new InputStreamReader(in))) {
String resource;
while ((resource = br.readLine()) != null) {
filenames.add(resource);
}
}
return filenames;
}
And where the getResourceFiles method is called:
List<String> names = Foo.getResourceFiles("/foo/bar/foobar");

Why do you even do all this? Why not just add URL to JAR to the URLClassLoader?
E.g.
URLClassLoader loader = new URLClassLoader(new File(jar).toURI().toURL());
Also you should probably make that URLClassLoader have your current classloader as parent, e.g.
URLClassLoader loader = new URLClassLoader(new File(jar).toURI().toURL(), Thread.currentThread().getContextClassLoader());

Inside a plugin, how to properly get a directory & it's contents from src/main/resources? [duplicate]

I am looking for a way to get a list of all resource names from a given classpath directory, something like a method List<String> getResourceNames (String directoryName).
For example, given a classpath directory x/y/z containing files a.html, b.html, c.html and a subdirectory d, getResourceNames("x/y/z") should return a List<String> containing the following strings:['a.html', 'b.html', 'c.html', 'd'].
It should work both for resources in filesystem and jars.
I know that I can write a quick snippet with Files, JarFiles and URLs, but I do not want to reinvent the wheel. My question is, given existing publicly available libraries, what is the quickest way to implement getResourceNames? Spring and Apache Commons stacks are both feasible.

Custom Scanner
Implement your own scanner. For example:
(limitations of this solution are mentioned in the comments)
private List<String> getResourceFiles(String path) throws IOException {
List<String> filenames = new ArrayList<>();
try (
InputStream in = getResourceAsStream(path);
BufferedReader br = new BufferedReader(new InputStreamReader(in))) {
String resource;
while ((resource = br.readLine()) != null) {
filenames.add(resource);
}
}
return filenames;
}
private InputStream getResourceAsStream(String resource) {
final InputStream in
= getContextClassLoader().getResourceAsStream(resource);
return in == null ? getClass().getResourceAsStream(resource) : in;
}
private ClassLoader getContextClassLoader() {
return Thread.currentThread().getContextClassLoader();
}
Spring Framework
Use PathMatchingResourcePatternResolver from Spring Framework.
Ronmamo Reflections
The other techniques might be slow at runtime for huge CLASSPATH values. A faster solution is to use ronmamo's Reflections API, which precompiles the search at compile time.

Here is the code
Source: forums.devx.com/showthread.php?t=153784
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.regex.Pattern;
import java.util.zip.ZipEntry;
import java.util.zip.ZipException;
import java.util.zip.ZipFile;
/**
* list resources available from the classpath # *
*/
public class ResourceList{
/**
* for all elements of java.class.path get a Collection of resources Pattern
* pattern = Pattern.compile(".*"); gets all resources
*
* #param pattern
* the pattern to match
* #return the resources in the order they are found
*/
public static Collection<String> getResources(
final Pattern pattern){
final ArrayList<String> retval = new ArrayList<String>();
final String classPath = System.getProperty("java.class.path", ".");
final String[] classPathElements = classPath.split(System.getProperty("path.separator"));
for(final String element : classPathElements){
retval.addAll(getResources(element, pattern));
}
return retval;
}
private static Collection<String> getResources(
final String element,
final Pattern pattern){
final ArrayList<String> retval = new ArrayList<String>();
final File file = new File(element);
if(file.isDirectory()){
retval.addAll(getResourcesFromDirectory(file, pattern));
} else{
retval.addAll(getResourcesFromJarFile(file, pattern));
}
return retval;
}
private static Collection<String> getResourcesFromJarFile(
final File file,
final Pattern pattern){
final ArrayList<String> retval = new ArrayList<String>();
ZipFile zf;
try{
zf = new ZipFile(file);
} catch(final ZipException e){
throw new Error(e);
} catch(final IOException e){
throw new Error(e);
}
final Enumeration e = zf.entries();
while(e.hasMoreElements()){
final ZipEntry ze = (ZipEntry) e.nextElement();
final String fileName = ze.getName();
final boolean accept = pattern.matcher(fileName).matches();
if(accept){
retval.add(fileName);
}
}
try{
zf.close();
} catch(final IOException e1){
throw new Error(e1);
}
return retval;
}
private static Collection<String> getResourcesFromDirectory(
final File directory,
final Pattern pattern){
final ArrayList<String> retval = new ArrayList<String>();
final File[] fileList = directory.listFiles();
for(final File file : fileList){
if(file.isDirectory()){
retval.addAll(getResourcesFromDirectory(file, pattern));
} else{
try{
final String fileName = file.getCanonicalPath();
final boolean accept = pattern.matcher(fileName).matches();
if(accept){
retval.add(fileName);
}
} catch(final IOException e){
throw new Error(e);
}
}
}
return retval;
}
/**
* list the resources that match args[0]
*
* #param args
* args[0] is the pattern to match, or list all resources if
* there are no args
*/
public static void main(final String[] args){
Pattern pattern;
if(args.length < 1){
pattern = Pattern.compile(".*");
} else{
pattern = Pattern.compile(args[0]);
}
final Collection<String> list = ResourceList.getResources(pattern);
for(final String name : list){
System.out.println(name);
}
}
}
If you are using Spring Have a look at PathMatchingResourcePatternResolver

Using Reflections
Get everything on the classpath:
Reflections reflections = new Reflections(null, new ResourcesScanner());
Set<String> resourceList = reflections.getResources(x -> true);
Another example - get all files with extension .csv from some.package:
Reflections reflections = new Reflections("some.package", new ResourcesScanner());
Set<String> resourceList = reflections.getResources(Pattern.compile(".*\\.csv"));

So in terms of the PathMatchingResourcePatternResolver this is what is needed in the code:
#Autowired
ResourcePatternResolver resourceResolver;
public void getResources() {
resourceResolver.getResources("classpath:config/*.xml");
}

If you use apache commonsIO you can use for the filesystem (optionally with extension filter):
Collection<File> files = FileUtils.listFiles(new File("directory/"), null, false);
and for resources/classpath:
List<String> files = IOUtils.readLines(MyClass.class.getClassLoader().getResourceAsStream("directory/"), Charsets.UTF_8);
If you don't know if "directoy/" is in the filesystem or in resources you may add a
if (new File("directory/").isDirectory())
or
if (MyClass.class.getClassLoader().getResource("directory/") != null)
before the calls and use both in combination...

The most robust mechanism for listing all resources in the classpath is currently to use this pattern with ClassGraph, because it handles the widest possible array of classpath specification mechanisms, including the new JPMS module system. (I am the author of ClassGraph.)
List<String> resourceNames;
try (ScanResult scanResult = new ClassGraph().acceptPaths("x/y/z").scan()) {
resourceNames = scanResult.getAllResources().getNames();
}

The Spring framework's PathMatchingResourcePatternResolver is really awesome for these things:
private Resource[] getXMLResources() throws IOException
{
ClassLoader classLoader = MethodHandles.lookup().getClass().getClassLoader();
PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(classLoader);
return resolver.getResources("classpath:x/y/z/*.xml");
}
Maven dependency:
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>LATEST</version>
</dependency>

This should work (if spring is not an option):
public static List<String> getFilenamesForDirnameFromCP(String directoryName) throws URISyntaxException, UnsupportedEncodingException, IOException {
List<String> filenames = new ArrayList<>();
URL url = Thread.currentThread().getContextClassLoader().getResource(directoryName);
if (url != null) {
if (url.getProtocol().equals("file")) {
File file = Paths.get(url.toURI()).toFile();
if (file != null) {
File[] files = file.listFiles();
if (files != null) {
for (File filename : files) {
filenames.add(filename.toString());
}
}
}
} else if (url.getProtocol().equals("jar")) {
String dirname = directoryName + "/";
String path = url.getPath();
String jarPath = path.substring(5, path.indexOf("!"));
try (JarFile jar = new JarFile(URLDecoder.decode(jarPath, StandardCharsets.UTF_8.name()))) {
Enumeration<JarEntry> entries = jar.entries();
while (entries.hasMoreElements()) {
JarEntry entry = entries.nextElement();
String name = entry.getName();
if (name.startsWith(dirname) && !dirname.equals(name)) {
URL resource = Thread.currentThread().getContextClassLoader().getResource(name);
filenames.add(resource.toString());
}
}
}
}
}
return filenames;
}

My way, no Spring, used during a unit test:
URI uri = TestClass.class.getResource("/resources").toURI();
Path myPath = Paths.get(uri);
Stream<Path> walk = Files.walk(myPath, 1);
for (Iterator<Path> it = walk.iterator(); it.hasNext(); ) {
Path filename = it.next();
System.out.println(filename);
}

With Spring it's easy. Be it a file, or folder, or even multiple files, there are chances, you can do it via injection.
This example demonstrates the injection of multiple files located in x/y/z folder.
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Service;
#Service
public class StackoverflowService {
#Value("classpath:x/y/z/*")
private Resource[] resources;
public List<String> getResourceNames() {
return Arrays.stream(resources)
.map(Resource::getFilename)
.collect(Collectors.toList());
}
}
It does work for resources in the filesystem as well as in JARs.

Used a combination of Rob's response.
final String resourceDir = "resourceDirectory/";
List<String> files = IOUtils.readLines(Thread.currentThread().getClass().getClassLoader().getResourceAsStream(resourceDir), Charsets.UTF_8);
for (String f : files) {
String data = IOUtils.toString(Thread.currentThread().getClass().getClassLoader().getResourceAsStream(resourceDir + f));
// ... process data
}

I think you can leverage the [Zip File System Provider][1] to achieve this. When using FileSystems.newFileSystem it looks like you can treat the objects in that ZIP as a "regular" file.
In the linked documentation above:
Specify the configuration options for the zip file system in the java.util.Map object passed to the FileSystems.newFileSystem method. See the [Zip File System Properties][2] topic for information about the provider-specific configuration properties for the zip file system.
Once you have an instance of a zip file system, you can invoke the methods of the [java.nio.file.FileSystem][3] and [java.nio.file.Path][4] classes to perform operations such as copying, moving, and renaming files, as well as modifying file attributes.
The documentation for the jdk.zipfs module in [Java 11 states][5]:
The zip file system provider treats a zip or JAR file as a file system and provides the ability to manipulate the contents of the file. The zip file system provider can be created by [FileSystems.newFileSystem][6] if installed.
Here is a contrived example I did using your example resources. Note that a .zip is a .jar, but you could adapt your code to instead use classpath resources:
Setup
cd /tmp
mkdir -p x/y/z
touch x/y/z/{a,b,c}.html
echo 'hello world' > x/y/z/d
zip -r example.zip x
Java
import java.io.IOException;
import java.net.URI;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.util.Collections;
import java.util.stream.Collectors;
public class MkobitZipRead {
public static void main(String[] args) throws IOException {
final URI uri = URI.create("jar:file:/tmp/example.zip");
try (
final FileSystem zipfs = FileSystems.newFileSystem(uri, Collections.emptyMap());
) {
Files.walk(zipfs.getPath("/")).forEach(path -> System.out.println("Files in zip:" + path));
System.out.println("-----");
final String manifest = Files.readAllLines(
zipfs.getPath("x", "y", "z").resolve("d")
).stream().collect(Collectors.joining(System.lineSeparator()));
System.out.println(manifest);
}
}
}
Output
Files in zip:/
Files in zip:/x/
Files in zip:/x/y/
Files in zip:/x/y/z/
Files in zip:/x/y/z/c.html
Files in zip:/x/y/z/b.html
Files in zip:/x/y/z/a.html
Files in zip:/x/y/z/d
-----
hello world

Neither of answers worked for me even though I had my resources put in resources folders and followed the above answers. What did make a trick was:
#Value("file:*/**/resources/**/schema/*.json")
private Resource[] resources;

Expanding on Luke Hutchinsons answer above, using his ClassGraph library, I was able to easily get a list of all files in a Resource folder with almost no effort at all.
Let's say that in your resource folder, you have a folder called MyImages. This is how easy it is to get a URL list of all the files in that folder:
import io.github.classgraph.ClassGraph;
import io.github.classgraph.ResourceList;
import io.github.classgraph.ScanResult;
public static LinkedList<URL> getURLList (String folder) {
LinkedList<URL> urlList = new LinkedList<>();
ScanResult scanResult = new ClassGraph().enableAllInfo().scan();
ResourceList resources = scanResult.getAllResources();
for (URL url : resources.getURLs()) {
if (url.toString().contains(folder)) {
urlList.addLast(url);
}
}
return urlList;
}
Then you simply do this:
LinkedList<URL> myURLFileList = getURLList("MyImages");
The URLs can then be loaded into streams or use Apache's FileUtils to copy the files somewhere else like this:
String outPath = "/My/Output/Path";
for(URL url : myURLFileList) {
FileUtils.copyURLToFile(url, new File(outPath, url.getFile()));
}
I think ClassGraph is a pretty slick library for making tasks like this very simple and easy to comprehend.

Based on #rob 's information above, I created the implementation which I am releasing to the public domain:
private static List<String> getClasspathEntriesByPath(String path) throws IOException {
InputStream is = Main.class.getClassLoader().getResourceAsStream(path);
StringBuilder sb = new StringBuilder();
while (is.available()>0) {
byte[] buffer = new byte[1024];
sb.append(new String(buffer, Charset.defaultCharset()));
}
return Arrays
.asList(sb.toString().split("\n")) // Convert StringBuilder to individual lines
.stream() // Stream the list
.filter(line -> line.trim().length()>0) // Filter out empty lines
.collect(Collectors.toList()); // Collect remaining lines into a List again
}
While I would not have expected getResourcesAsStream to work like that on a directory, it really does and it works well.

How to bind input externally to xquery using saxon?

I have to invoke external java methods in xquery using saxon HE. I could able to invoke the methods with the below code. But the problem is i want to bind my input externally.
final Configuration config = new Configuration();
config.registerExtensionFunction(new ShiftLeft());
final StaticQueryContext sqc = new StaticQueryContext(config);
final XQueryExpression exp = sqc.compileQuery(new FileReader(
"input/names.xq"));
final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
String xml = "<student_list><student><name>George Washington</name><major>Politics</major><phone>312-123-4567</phone><email>gw#example.edu</email></student><student><name>Janet Jones</name><major>Undeclared</major><phone>311-122-2233</phone><email>janetj#example.edu</email></student><student><name>Joe Taylor</name><major>Engineering</major><phone>211-111-2333</phone><email>joe#example.edu</email></student></student_list>";
DocumentBuilderFactory newInstance = DocumentBuilderFactory.newInstance();
newInstance.setNamespaceAware(true);
Document parse = newInstance.newDocumentBuilder().parse(new InputSource(new StringReader(xml)));
DocumentWrapper sequence = new DocumentWrapper(parse, "", config);
StructuredQName qname = new StructuredQName("", "", "student_list");
dynamicContext.setParameter(qname, sequence);
Properties props = new Properties();
final SequenceIterator iter = exp.iterator(dynamicContext);
props.setProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
props.setProperty(OutputKeys.INDENT, "yes");
StringWriter writer = new StringWriter();
QueryResult.serializeSequence(iter, config, writer, props);
System.out.println("Result is " + writer);
names.xq
declare namespace eg="http://example.com/saxon-extension";
declare namespace xs = "http://www.w3.org/2001/XMLSchema";
declare variable $student_list as element(*) external;
<Students>
<value> {
let $n := eg:shift-left(2, 2)
return $n
}</value>
<student_names>
{ $student_list//student_list/student/name }
</student_names>
</Students>
But getting the below error
Error at procedure student_list on line 3 of students.xml:
XPTY0004: Required item type of value of variable $student_list is element(); supplied
value has item type document-node(element(Q{}student_list))
net.sf.saxon.trans.XPathException: Required item type of value of variable $student_list is element(); supplied value has item type document- node(element(Q{}student_list))
at net.sf.saxon.expr.ItemTypeCheckingFunction.testConformance(ItemTypeCheckingFunction.java:69)
at net.sf.saxon.expr.ItemTypeCheckingFunction.mapItem(ItemTypeCheckingFunction.java:50)
at net.sf.saxon.expr.ItemMappingIterator.next(ItemMappingIterator.java:95)
at net.sf.saxon.expr.CardinalityCheckingIterator.<init>(CardinalityCheckingIterator.java:52)
at net.sf.saxon.type.TypeHierarchy.applyFunctionConversionRules(TypeHierarchy.java:230)
at net.sf.saxon.expr.instruct.GlobalParameterSet.convertParameterValue(GlobalParameterSet.java:105)
at net.sf.saxon.expr.instruct.Bindery.useGlobalParameter(Bindery.java:136)
at net.sf.saxon.expr.instruct.GlobalParam.evaluateVariable(GlobalParam.java:62)
at net.sf.saxon.expr.GlobalVariableReference.evaluateVariable(GlobalVariableReference.java:105)
at net.sf.saxon.expr.VariableReference.evaluateItem(VariableReference.java:460)
at net.sf.saxon.expr.Atomizer.evaluateItem(Atomizer.java:313)
at net.sf.saxon.expr.Atomizer.evaluateItem(Atomizer.java:35)
at net.sf.saxon.expr.AtomicSequenceConverter.evaluateItem(AtomicSequenceConverter.java:275)
at net.sf.saxon.expr.AtomicSequenceConverter.evaluateItem(AtomicSequenceConverter.java:30)
at net.sf.saxon.functions.Doc.doc(Doc.java:235)
at net.sf.saxon.functions.Doc.evaluateItem(Doc.java:190)
at net.sf.saxon.functions.Doc.evaluateItem(Doc.java:28)
at net.sf.saxon.expr.SimpleStepExpression.iterate(SimpleStepExpression.java:85)
at net.sf.saxon.expr.SlashExpression.iterate(SlashExpression.java:842)
at net.sf.saxon.expr.sort.DocumentSorter.iterate(DocumentSorter.java:168)
at net.sf.saxon.expr.SlashExpression.iterate(SlashExpression.java:842)
at net.sf.saxon.expr.sort.DocumentSorter.iterate(DocumentSorter.java:168)
at net.sf.saxon.expr.Expression.process(Expression.java:552)
at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
at net.sf.saxon.expr.instruct.ElementCreator.constructElement(ElementCreator.java:539)
at net.sf.saxon.expr.instruct.ElementCreator.evaluateItem(ElementCreator.java:476)
at net.sf.saxon.expr.instruct.Instruction.iterate(Instruction.java:363)
at net.sf.saxon.query.XQueryExpression.iterator(XQueryExpression.java:332)
at com.example.saxon.ExternalMethodCaller.main(ExternalMethodCaller.java:77)
Thanks in advance..

Unless you have a very good reason not to, my advice is to use Snappi (the Saxon 9 API, or s9api):
Processor saxon = new Processor(false);
saxon.registerExtensionFunction(new MyExtension());
XQueryCompiler compiler = saxon.newXQueryCompiler();
XQueryExecutable exec = compiler.compile(new File("input/names.xq"));
XQueryEvaluator query = exec.load();
DocumentBuilder builder = saxon.newDocumentBuilder();
String students = "<xml>...</xml>";
Source src = new StreamSource(new StringReader(students));
XdmNode doc = builder.build(src);
query.setExternalVariable(new QName("student_list"), doc);
XdmValue result = query.evaluate();
With MyExtension looking something like the following:
public class MyExtension
implements ExtensionFunction
{
#Override
public QName getName()
{
return new QName("http://example.org/my-project", "my-fun");
}
#Override
public SequenceType getResultType()
{
return SequenceType.makeSequenceType(
ItemType.INTEGER, OccurrenceIndicator.ONE);
}
#Override
public SequenceType[] getArgumentTypes()
{
return new SequenceType[] {
SequenceType.makeSequenceType(
ItemType.INTEGER, OccurrenceIndicator.ONE),
SequenceType.makeSequenceType(
ItemType.INTEGER, OccurrenceIndicator.ONE)
};
}
#Override
public XdmValue call(XdmValue[] args) throws SaxonApiException
{
long first = ((XdmAtomicValue)args[0].itemAt(0)).getLongValue();
long second = ((XdmAtomicValue)args[0].itemAt(0)).getLongValue();
long result = ...;
return new XdmAtomicValue(result);
}
}
See the documentation at http://www.saxonica.com/documentation9.5/extensibility/integratedfunctions/ext-simple-J.html for details.
EXPath also has a project called tools-saxon, containing several tools for using Saxon in Java. Including extension functions. It introduces the concept of a function library, which is convenient if you have several extension functions. It also introduces a function definition builder, allowing one to build a function definition with as less boiler plate code as possible (and providing convenient shortcuts for type sequences). In the above code, replace the function registering (the first 2 lines) by:
Processor saxon = new Processor(false);
Library lib = new MyLibrary();
lib.register(saxon.getUnderlyingConfiguration());
and replace the extension class with the 2 following classes (a library and a function, resp.):
public class MyLibrary
extends Library
{
public MyLibrary()
{
super("http://example.org/my-project", "my");
}
#Override
protected Function[] functions()
{
return new Function[] {
new MyFunction(this)
};
}
}
public class MyFunction
extends Function
{
public MyFunction(Library lib)
{
super(lib);
}
#Override
protected Definition makeDefinition()
{
return library()
.function(this, "my-fun")
.returns(Types.SINGLE_INTEGER)
.param(Types.SINGLE_INTEGER, "first")
.param(Types.SINGLE_INTEGER, "second")
.make();
}
#Override
public Sequence call(XPathContext ctxt, Sequence[] args)
throws XPathException
{
Parameters params = checkParams(args);
long first = params.asLong(0, true);
long second = params.asLong(1, true);
long result = 0;
return Return.value(result);
}
}
See all informatio on the project home on Github, at https://github.com/expath/tools-saxon.
Note: not tested.

How to generate multiple, slightly different XSD schemas from one Java model with JAXB?

I have a set of related Java classes, which are able to hold data I need. Below is a simplified class diagram of what I have:
Now I need to import data from XML and for that I want to generate XSD schema. The problem is that I want several XSD schemas like this:
One that allows the whole data graph to be imported.
One that allows only RootNote.fieldA and ChildNodeA.
One that allows only RootNote.fieldB and ChildNodeB.
I can easily generate XSD that meets the requirements of nr.1 using JAXB (programmatically). But is there a way to do that for cases nr.2 and nr.3 for the same classes? In other words, it seems I need something like "profiles" in JAXB.
Update:
Here is how I generate XSD schema:
JAXBContext jc = JAXBContext.newInstance(RootNode.class);
final File baseDir = new File(".");
class MySchemaOutputResolver extends SchemaOutputResolver {
public Result createOutput( String namespaceUri, String suggestedFileName ) throws IOException {
return new StreamResult(new File(baseDir,suggestedFileName));
}
}
jc.generateSchema(new MySchemaOutputResolver());

This is not a full answer, just an idea.
You probably use the javax.xml.bind.JAXBContext.generateSchema(SchemaOutputResolver) method to generate your schema, so you basically use a specific JAXBContext instance. This instance is built based on the annotations in classes. When building the context, these annotations are read an organized into a model which is then used for all the operations.
So to generate different schemas you probably need to create different contexts. You can't change the annotations per case, but you can read annotations in different ways.
Take a look at the AnnotationReader. This is what JAXB RI uses behind the scenes to load annotations from Java classes. You can create your own implementation and use it when creating the JAXBContext. Here's an example of something similar:
final AnnotationReader<Type, Class, Field, Method> annotationReader = new AnnoxAnnotationReader();
final Map<String, Object> properties = new HashMap<String, Object>();
properties.put(JAXBRIContext.ANNOTATION_READER, annotationReader);
final JAXBContext context = JAXBContext.newInstance(
"org.jvnet.annox.samples.po",
Thread.currentThread().getContextClassLoader(),
properties);
So how about writing your own annotation reader, which would consider what you call "profiles"? You can invent your own annotation #XmlSchemaProfile(name="foo"). Your annotation reader would then check if this annotation is present with the desired value and then either return it or ignore it. You'll be able to build different contexts from the same Java model - and consequently produce different schemas according to profiles defined by your #XmlSchemaProfile annotations.

I found a solution that suited me. The idea is to output the result of XSD generation into an XML Document (in-memory DOM). JAXB allows that. After this, you can manipulate the document any way you wish, adding or removing parts.
I wrote some filters that whitelist or blacklist fields (in XSD they are elements) and classes (in XSD they are complex types). While I see a lot of potential problems with this approach, it did the job in my case. Below is the code for case 2 schema:
// This SchemaOutputResolver implementation saves XSD into DOM
static class DOMResultSchemaOutputResolver extends SchemaOutputResolver {
private List<DOMResult> results = new LinkedList<DOMResult>();
#Override
public Result createOutput(String ns, String file) throws IOException {
DOMResult result = new DOMResult();
result.setSystemId(file);
results.add(result);
return result;
}
public Document getDocument() {
return (Document)results.get(0).getNode();
}
public String getFilename() {
return results.get(0).getSystemId();
}
}
// This method serializes the DOM into file
protected void serializeXsdToFile(Document xsdDocument, String filename) throws IOException {
OutputFormat format = new OutputFormat(xsdDocument);
format.setIndenting(true);
FileOutputStream os = new FileOutputStream(filename);
XMLSerializer serializer = new XMLSerializer(os, format);
serializer.serialize(xsdDocument);
}
#Test
public void generateSchema2() throws JAXBException, IOException, XPathExpressionException {
JAXBContext context = JAXBContext.newInstance(RootNode.class);
DOMResultSchemaOutputResolver schemaOutputResolver = new DOMResultSchemaOutputResolver();
context.generateSchema(schemaOutputResolver);
// Do your manipulations here as you want. Below is just an example!
filterXsdDocumentComplexTypes(schemaOutputResolver.getDocument(), asList("childNodeA"), true);
filterXsdDocumentElements(schemaOutputResolver.getDocument(), asList("fieldB"));
serializeXsdToFile(schemaOutputResolver.getDocument(), "xf.xsd");
}
private boolean shouldComplexTypeBeDeleted(String complexTypeName, List<String> complexTypes, boolean whitelist) {
return (whitelist && !complexTypes.contains(complexTypeName)) || (!whitelist && complexTypes.contains(complexTypeName));
}
protected void filterXsdDocumentComplexTypes(Document xsdDocument, List<String> complexTypes, boolean whitelist) throws XPathExpressionException {
XPath xPath = XPathFactory.newInstance().newXPath();
NodeList complexTypeNodes = (NodeList)xPath.evaluate("//*[local-name() = 'complexType']", xsdDocument, XPathConstants.NODESET);
for (int i = 0; i < complexTypeNodes.getLength(); i++) {
Node node = complexTypeNodes.item(i);
Node complexTypeNameNode = node.getAttributes().getNamedItem("name");
if (complexTypeNameNode != null) {
if (shouldComplexTypeBeDeleted(complexTypeNameNode.getNodeValue(), complexTypes, whitelist)) {
node.getParentNode().removeChild(node);
}
}
}
NodeList elements = (NodeList)xPath.evaluate("//*[local-name() = 'element']", xsdDocument, XPathConstants.NODESET);
for (int i = 0; i < elements.getLength(); i++) {
Node node = elements.item(i);
Node typeNameNode = node.getAttributes().getNamedItem("type");
if (typeNameNode != null) {
if (shouldComplexTypeBeDeleted(typeNameNode.getNodeValue(), complexTypes, whitelist) && !typeNameNode.getNodeValue().startsWith("xs")) {
node.getParentNode().removeChild(node);
}
}
}
}
protected void filterXsdDocumentElements(Document xsdDocument, List<String> blacklistedElements) throws XPathExpressionException {
XPath xPath = XPathFactory.newInstance().newXPath();
NodeList elements = (NodeList)xPath.evaluate("//*[local-name() = 'element']", xsdDocument, XPathConstants.NODESET);
for (int i = 0; i < elements.getLength(); i++) {
Node node = elements.item(i);
if (blacklistedElements.contains(node.getAttributes().getNamedItem("name").getNodeValue())) {
node.getParentNode().removeChild(node);
}
}
}