Using Antlr to get identifiers and function names

Using Antlr to get identifiers and function names - java

I'm trying to use and understand AntLR, this is new to me. My purpose is to read a source code file written in C and extract from it the identifiers (variables and function names).
In my C grammar (file C.g4) consider:
identifierList
: Identifier
| identifierList Comma Identifier
;
Identifier
: IdentifierNondigit
( IdentifierNondigit
| Digit
)*
;
After generation of parser and listener I create my own listener to the identifierList.
Note that MyCListener class extends CBaseListener:
public class MyCListener extends CBaseListener {
#Override
public void enterIdentifierList(CParser.IdentifierListContext ctx) {
List<ParseTree> children = ctx.children;
for (ParseTree parseTree : children) {
System.out.println(parseTree.getText());
}
}
Then I have this in main class:
String fileurl = "C:/example.c";
CLexer lexer;
try {
lexer = new CLexer(new ANTLRFileStream(fileurl));
CommonTokenStream tokens = new CommonTokenStream(lexer);
CParser parser = new CParser(tokens);
CParser.IdentifierListContext identifierContext = parser.identifierList();
ParseTreeWalker walker = new ParseTreeWalker();
MyCListener listener = new MyCListener();
walker.walk(listener, identifierContext);
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
Where example.c is:
int main() {
// this is C
int i=0; // i is int
/* double j=0.0;
C
*/
}
What am I doing wrong?
Maybe I didn't write MyCListener properly, or identifierList is not what I need to listen... Really don't know. I'm sorry, but I didn't even understand my output, why is there a lexical error?:
line 3:4 mismatched input '(' expecting {<EOF>, ','}
main
(
)
{
int
i
=
0
;
}
As you see, I'm very confused about this. Can somebody help me ? Please...

With this line:
CParser.IdentifierListContext identifierContext = parser.identifierList();
you're trying to parse your entire input as an identifierList. But your input isn't just that.
Assuming you're using the C.g4 from the ANTLR4 Github repository, try to let the parser start at the entry point of the grammar (which is the rule compilationUnit):
MyCListener listener = new MyCListener();
ParseTreeWalker.DEFAULT.walk(listener, parser.compilationUnit());
EDIT
Here's a quick demo:
public class Main {
public static void main(String[] args) throws Exception {
final List<String> identifiers = new ArrayList<String>();
String source = "int main() {\n" +
"\n" +
"// this is C\n" +
"\n" +
" int i=0; // i is int\n" +
" /* double j=0.0;\n" +
" C\n" +
" */\n" +
"}";
CLexer lexer = new CLexer(new ANTLRInputStream(source));
CParser parser = new CParser(new CommonTokenStream(lexer));
ParseTreeWalker.DEFAULT.walk(new CBaseListener(){
#Override
public void enterDirectDeclarator(#NotNull CParser.DirectDeclaratorContext ctx) {
if (ctx.Identifier() != null) {
identifiers.add(ctx.Identifier().getText());
}
}
// Perhaps override other rules that use `Identifier`
}, parser.compilationUnit());
System.out.println("identifiers -> " + identifiers);
}
}
which would print:
identifiers -> [main, i]

Related

Initialize multiple numeric fields at once in JAVA that begin with certain values

I am working on a Java class that contains a ton of numeric fields. Most of them would begin with something like 'CMTH' or 'FYTD'. Is it possible to initialize all fields of the same type that begin or end with a certain value. For example I have the following fields:
CMthRepCaseACR CMthRepUnitACR CMthRecCaseACR CMthRecUnitACR CMthHecCaseACR CMthHecUnitACR FYTDHecCaseACR FYTDHecUnitACR CMthBBKCaseACR CMthBBKUnitACR CMthPIHCaseACR .
I am trying to figure if it is possible to initialize all fields to zero that end with an 'ACR' or begin with an 'Cmth"
I know I can do something like cmtha = cmthb = cmthc = 0 but I was wondering there was a command where you can some kind of mask to initialize
Thanks

Assuming that you cannot change that said Java class (and e.g. use a collection or map to store the values) your best bet is probably reflection (see also: Trail: The Reflection API). Reflection gives you access to all fields of the class and you can then implement whatever matching you'd like.
Here's a short demo to get you started, minus error handling, sanity checks and adaptions to your actual class:
import java.util.stream.Stream;
public class Demo {
private static class DemoClass {
private int repCaseACR = 1;
private int CMthRepUnit = 2;
private int foo = 3;
private int bar = 4;
#Override
public String toString() {
return "DemoClass [repCaseACR=" + repCaseACR + ", CMthRepUnit=" + CMthRepUnit + ", foo=" + foo + ", bar="
+ bar + "]";
}
}
public static void main(String[] args) {
DemoClass demoClass = new DemoClass();
System.out.println("before: " + demoClass);
resetFields(demoClass, "CMth", null);
System.out.println("after prefix reset: " + demoClass);
resetFields(demoClass, null, "ACR");
System.out.println("after suffix reset: " + demoClass);
}
private static void resetFields(DemoClass instance, String prefix, String suffix) {
Stream.of(instance.getClass().getDeclaredFields())
.filter(field ->
(prefix != null && field.getName().startsWith(prefix))
|| (suffix != null && field.getName().endsWith(suffix)))
.forEach(field -> {
field.setAccessible(true);
try {
field.set(instance, 0);
} catch (IllegalArgumentException | IllegalAccessException e) {
// TODO handle me
}
});
}
}
Output:
before: DemoClass [repCaseACR=1, CMthRepUnit=2, foo=3, bar=4]
after prefix reset: DemoClass [repCaseACR=1, CMthRepUnit=0, foo=3, bar=4]
after suffix reset: DemoClass [repCaseACR=0, CMthRepUnit=0, foo=3, bar=4]
Note: Both links are seriously dated but the core functionality of reflection is still the same.

Parsing input from file, delimiters, loops, java

The overall project is creating a system manager for airports. It keeps track of airports, flights, seating sections, seats and other relevent info for each of those catagories. The initial system is set up by importing from a file that's formatted a certain way. I'm having problems parsing the file properly to set up the initial system. the data is parsed from the file and used as method parameters to create the objects: Airport, Airline, Flight, FlightSection, and Seat.
the formatting is:
[list-of-airport-codes] {list-of-airlines}
list-of-airport-codes ::= comma-separated strings
list-of-airlines ::= airline-name1[flightinfo-list1], airline-name2[flightinfo-list2], airlinename3[flightinfo-list3], …
flightinfo-list ::= flightID1|flightdate1|originAirportCode1|destinationAirportCode1[flightsectionlist1], flightID2|flightdate2|originAirportCode2|destinationAirportCode2[flightsection-list2], …
flightdate ::= year, month, day-of-month, hours, minutes
flightsection-list ::= sectionclass: seat-price: layout: number-of-rows, …
sectionclass ::= F, B, E (for first class, business class, economy class)
layout ::= S, M, W (different known seating layouts)
example:
[DEN,NYC,SEA,LAX]{AMER[AA1|2018,10,8,16,30|DEN|LAX[E:200:S:4,F:500:S:2],
AA2|2018,8,9,7,30|LAX|DEN[E:200:S:5,F:500:S:3], …], UNTD[UA21|2018,11,8,12,30|NYC|SEA[E:300:S:6,F:800:S:3], UA12|2018,8,9,7,30|SEA|DEN[B:700:S:5, F:1200:S:2], …], FRONT[…], USAIR[…]}
I tried brute forcing it using a combination of delimiters and while loops. The code successfully creates the Airports, first Airline and Flighsections, but when it gets to creating the second airline it crashes, because i'm not looping properly, and having a hard time getting it right. My code for it as of now, is a mess, and if you're willing to look at it, I would appreciate any constructive input. My question is what would be a better way to approach this? A different design approach? Maybe a smarter way to use the delimiters?
Thanks in advance for your help!!
here's what i've tried.
private void readFile(File file){
System.out.println("reading file");
Scanner tempScan;
String result;
String temp = "";
scan.useDelimiter("\\[|\\{");
try{
// AIRPORTS
result = scan.next();
tempScan = new Scanner(result);
tempScan.useDelimiter(",|\\]");
while(tempScan.hasNext()){
temp = tempScan.next();
sysMan.createAirport(temp);
}
tempScan.close();
/* AIRLINE
* FLIGHT
* FLIGHTSECTION
*/
do{
// AIRLINE (loop<flight & fsection>)
result = scan.next();
sysMan.createAirline(result);
// FLIGHT
result = scan.next();
tempScan = new Scanner(result);
do{
tempScan.useDelimiter(",|\\|");
ArrayList flightInfo = new ArrayList();
while(tempScan.hasNext()){
if(tempScan.hasNextInt()){
flightInfo.add(tempScan.nextInt());
} else {
flightInfo.add(tempScan.next());
}
}
tempScan.close();
sysMan.createFlight(sysMan.getLastAddedAirline(),(String)flightInfo.get(0), (int)flightInfo.get(1), (int)flightInfo.get(2), (int)flightInfo.get(3), (int)flightInfo.get(4), (int)flightInfo.get(5), (String)flightInfo.get(6), (String)flightInfo.get(7));
// FLIGHTSECTION (loop<itself>)
result = scan.next();
tempScan = new Scanner(result);
tempScan.useDelimiter(",|:|\\]");
ArrayList sectInfo = new ArrayList();
int i = 1;
while(!temp.contains("|")){
if(tempScan.hasNextInt()){
sectInfo.add(tempScan.nextInt());
} else {
temp = tempScan.next();
if(temp.equals(""))
break;
char c = temp.charAt(0);
sectInfo.add(c);
}
if(i == 4){
sysMan.createSection(sysMan.getLastAddedAirline(), sysMan.getLastAddedFlightID(), (char)sectInfo.get(0), (int)sectInfo.get(1), (char)sectInfo.get(2), (int)sectInfo.get(3));
i = 1;
sectInfo = null;
sectInfo = new ArrayList();
continue;
}
i++;
}
}while(!temp.equals("\\s+"));
}while(!temp.contains("\\s+"));
}catch(NullPointerException e){
System.err.println(e);
}
}

I'd rather chunk it down by regexp mathing the outer bounds, have a look, I took it a couple of levels broken.
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Tokeni {
static String yolo = "[DEN,NYC,SEA,LAX]{AMER["
+ "AA1|2018,10,8,16,30|DEN|LAX[E:200:S:4,F:500:S:2],"
+ "AA2|2018,8,9,7,30|LAX|DEN[E:200:S:5,F:500:S:3]],"
+ "UNTD[UA21|2018,11,8,12,30|NYC|SEA[E:300:S:6,F:800:S:3],"
+ "UA12|2018,8,9,7,30|SEA|DEN[B:700:S:5, F:1200:S:2]]}";
public static void main(String[] args) {
Matcher airportCodesMatcher = Pattern.compile("\\[(.*?)\\]").matcher(yolo);
airportCodesMatcher.find();
String[] airportCodes = airportCodesMatcher.group(1).split(",");
Matcher airLinesMatcher = Pattern.compile("\\{(.*?)\\}").matcher(yolo);
airLinesMatcher.find();
String airLinesStr = airLinesMatcher.group(1);
System.out.println(airLinesStr);
Pattern airLinePattern = Pattern.compile("\\D+\\[(.*?)\\]\\]");
Matcher airLineMatcher = airLinePattern.matcher(airLinesStr);
while( airLineMatcher.find() ) {
String airLineStr = airLineMatcher.group(0).trim();
if(airLineStr.startsWith(",")) {
airLineStr = airLineStr.substring(1, airLineStr.length()).trim();
}
System.out.println(airLineStr);
Matcher airLineNameMatcher = Pattern.compile("[A-Z]+").matcher(airLineStr);
airLineNameMatcher.find();
String airLineName = airLineNameMatcher.group(0).trim();
System.out.println(airLineName);
airLineStr = airLineStr.substring(airLineStr.indexOf("[")+1, airLineStr.length());
Matcher airLineInfoMatcher = Pattern.compile("\\D+(.*?)\\]").matcher(airLineStr);
while(airLineInfoMatcher.find()) {
String airLineInfoStr = airLineInfoMatcher.group(0).trim();
if(airLineInfoStr.startsWith(",")) {
airLineInfoStr = airLineInfoStr.substring(1, airLineInfoStr.length()).trim();
}
System.out.println(airLineInfoStr);
}
}
}
}

Refactor parameter names programmatically

Using eclipse's jdt refactoring framework, I am trying to convert two different code bases to the same names. They are almost identical codebases except that names are different.
Function/Field/Class renaming works fine, but when it comes to parameters it yells at me that the workbench is not created yet. However i'm trying to do this in a headless manor.
private void refactor(String task, IJavaElement element, String new_name) throws CoreException
{
RefactoringStatus status = new RefactoringStatus();
RefactoringContribution contrib = RefactoringCore.getRefactoringContribution(task);
RenameJavaElementDescriptor rnDesc = (RenameJavaElementDescriptor)contrib.createDescriptor();
rnDesc.setFlags(JavaRefactoringDescriptor.JAR_MIGRATION | JavaRefactoringDescriptor.JAR_REFACTORING);
rnDesc.setProject(element.getJavaProject().getProject().getName());
rnDesc.setUpdateReferences(true);
rnDesc.setJavaElement(element);
rnDesc.setNewName(new_name);
Refactoring ref = rnDesc.createRefactoring(status);
ref.checkInitialConditions(NULL_MON);
ref.checkFinalConditions(NULL_MON);
Change change = ref.createChange(NULL_MON);
change.perform(NULL_MON);
}
This works fine:
for (IMethod method : type.getMethods())
{
refactor(IJavaRefactorings.RENAME_METHOD, method, {new name});
}
This does not:
for (IMethod method : type.getMethods())
{
for (ILocalVariable param : method.getParameters())
{
refactor(IJavaRefactorings.RENAME_LOCAL_VARIABLE, param, {new name});
}
}
And the error, not really helpful as I said I need to do this in a headless manor {so can't make workbench}
java.lang.IllegalStateException: Workbench has not been created yet.
at org.eclipse.ui.PlatformUI.getWorkbench(PlatformUI.java:92)
at org.eclipse.jdt.internal.ui.javaeditor.ASTProvider.install(ASTProvider.java:245)
at org.eclipse.jdt.internal.ui.javaeditor.ASTProvider.<init>(ASTProvider.java:236)
at org.eclipse.jdt.internal.ui.JavaPlugin.getASTProvider(JavaPlugin.java:710)
at org.eclipse.jdt.ui.SharedASTProvider.getAST(SharedASTProvider.java:128)
at org.eclipse.jdt.internal.corext.refactoring.util.RefactoringASTParser.parseWithASTProvider(RefactoringASTParser.java:119)
at org.eclipse.jdt.internal.corext.refactoring.rename.RenameLocalVariableProcessor.initAST(RenameLocalVariableProcessor.java:231)
at org.eclipse.jdt.internal.corext.refactoring.rename.RenameLocalVariableProcessor.checkInitialConditions(RenameLocalVariableProcessor.java:218)
at org.eclipse.ltk.core.refactoring.participants.ProcessorBasedRefactoring.checkInitialConditions(ProcessorBasedRefactoring.java:203)
UPDATE: Made some progress, now I can refactor functions that are not overrides. But any function that overrides another or an interface screws up:
F_ARGUMENTS = JavaRefactoringDescriptor.class.getDeclaredField("fArguments");
F_ARGUMENTS.setAccessible(true);
private void refactor(IMethod method, String[] names) throws CoreException
{
/* My attempt to fix the interface issues, causes duplicate functions instead of renaming the parameters
IMethod parent = null;
if (method.getDeclaringType().isInterface())
{
parent = MethodChecks.overridesAnotherMethod(method, method.getDeclaringType().newSupertypeHierarchy(NULL_MON));
}
else if (MethodChecks.isVirtual(method))
{
ITypeHierarchy hierarchy = method.getDeclaringType().newTypeHierarchy(NULL_MON);
parent = MethodChecks.isDeclaredInInterface(method, hierarchy, NULL_MON);
if (parent == null)
{
parent = MethodChecks.overridesAnotherMethod(method, hierarchy);
}
}
parent = (parent == null ? method : parent);
if (!method.equals(parent))
{
refactor(parent, names);
return;
}*/
String task = IJavaRefactorings.CHANGE_METHOD_SIGNATURE;
RefactoringStatus status = new RefactoringStatus();
ChangeMethodSignatureRefactoringContribution contrib = (ChangeMethodSignatureRefactoringContribution)RefactoringCore.getRefactoringContribution(task);
ChangeMethodSignatureDescriptor desc = (ChangeMethodSignatureDescriptor)contrib.createDescriptor();
desc.setFlags(JavaRefactoringDescriptor.JAR_MIGRATION |
JavaRefactoringDescriptor.JAR_REFACTORING |
RefactoringDescriptor.MULTI_CHANGE |
RefactoringDescriptor.STRUCTURAL_CHANGE);
Map<String, String> args = null;
try
{
args = (Map<String, String>)F_ARGUMENTS.get(desc);
}
catch (Exception e)
{
e.printStackTrace();
}
String project = method.getJavaProject().getProject().getName();
desc.setProject(method.getJavaProject().getProject().getName());
args.put("input", JavaRefactoringDescriptorUtil.elementToHandle(project, method));
args.put("name", method.getElementName());
args.put("deprecate", "false");
args.put("delegate", "true");
boolean changed = false;
int x = 0;
for (ILocalVariable param : method.getParameters())
{
if (!param.getElementName().equals(names[x]))
{
changed = true;
}
String type = "String"; //Doesn't seem to actually matter as long as they are both the same
String info = type + " " + param.getElementName() + " " + x + " " +
type + " " + names[x] + " false";
args.put("parameter" + (x + 1), info);
x++;
}
if (changed)
{
refactor(desc.createRefactoring(status));
}
}

This is what I came up with:
ChangeSignatureProcessor changeSignatureProcessor = new ChangeSignatureProcessor((IMethod) node.resolveBinding().getJavaElement());
ParameterInfo info=new ParameterInfo("FormContext", "formContext", ParameterInfo.INDEX_FOR_ADDED);
info.setDefaultValue("formContext");
changeSignatureProcessor.getParameterInfos().add(0,info);
RefactoringStatus status = new RefactoringStatus();
CheckConditionsContext context= new CheckConditionsContext();
context.add(new ValidateEditChecker(null));
context.add(new ResourceChangeChecker());
changeSignatureProcessor.checkInitialConditions(monitor);
changeSignatureProcessor.checkFinalConditions(monitor,context);
changeSignatureProcessor.createChange(monitor).perform(monitor);

In Java, how do I parse an xml schema (xsd) to learn what's valid at a given element?

I'd like to be able to read in an XML schema (i.e. xsd) and from that know what are valid attributes, child elements, values as I walk through it.
For example, let's say I have an xsd that this xml will validate against:
<root>
<element-a type="something">
<element-b>blah</element-b>
<element-c>blahblah</element-c>
</element-a>
</root>
I've tinkered with several libraries and I can confidently get <root> as the root element. Beyond that I'm lost.
Given an element I need to know what child elements are required or allowed, attributes, facets, choices, etc. Using the above example I'd want to know that element-a has an attribute type and may have children element-b and element-c...or must have children element-b and element-c...or must have one of each...you get the picture I hope.
I've looked at numerous libraries such as XSOM, Eclipse XSD, Apache XmlSchema and found they're all short on good sample code. My search of the Internet has also been unsuccessful.
Does anyone know of a good example or even a book that demonstrates how to go through an XML schema and find out what would be valid options at a given point in a validated XML document?
clarification
I'm not looking to validate a document, rather I'd like to know the options at a given point to assist in creating or editing a document. If I know "I am here" in a document, I'd like to determing what I can do at that point. "Insert one of element A, B, or C" or "attach attribute 'description'".

This is a good question. Although, it is old, I did not find an acceptable answer. The thing is that the existing libraries I am aware of (XSOM, Apache XmlSchema) are designed as object models. The implementors did not have the intention to provide any utility methods — you should consider implement them yourself using the provided object model.
Let's see how querying context-specific elements can be done by the means of Apache XmlSchema.
You can use their tutorial as a starting point. In addition, Apache CFX framework provides the XmlSchemaUtils class with lots of handy code examples.
First of all, read the XmlSchemaCollection as illustrated by the library's tutorial:
XmlSchemaCollection xmlSchemaCollection = new XmlSchemaCollection();
xmlSchemaCollection.read(inputSource, new ValidationEventHandler());
Now, XML Schema defines two kinds of data types:
Simple types
Complex types
Simple types are represented by the XmlSchemaSimpleType class. Handling them is easy. Read the documentation: https://ws.apache.org/commons/XmlSchema/apidocs/org/apache/ws/commons/schema/XmlSchemaSimpleType.html. But let's see how to handle complex types. Let's start with a simple method:
#Override
public List<QName> getChildElementNames(QName parentElementName) {
XmlSchemaElement element = xmlSchemaCollection.getElementByQName(parentElementName);
XmlSchemaType type = element != null ? element.getSchemaType() : null;
List<QName> result = new LinkedList<>();
if (type instanceof XmlSchemaComplexType) {
addElementNames(result, (XmlSchemaComplexType) type);
}
return result;
}
XmlSchemaComplexType may stand for both real type and for the extension element. Please see the public static QName getBaseType(XmlSchemaComplexType type) method of the XmlSchemaUtils class.
private void addElementNames(List<QName> result, XmlSchemaComplexType type) {
XmlSchemaComplexType baseType = getBaseType(type);
XmlSchemaParticle particle = baseType != null ? baseType.getParticle() : type.getParticle();
addElementNames(result, particle);
}
When you handle XmlSchemaParticle, consider that it can have multiple implementations. See: https://ws.apache.org/commons/XmlSchema/apidocs/org/apache/ws/commons/schema/XmlSchemaParticle.html
private void addElementNames(List<QName> result, XmlSchemaParticle particle) {
if (particle instanceof XmlSchemaAny) {
} else if (particle instanceof XmlSchemaElement) {
} else if (particle instanceof XmlSchemaGroupBase) {
} else if (particle instanceof XmlSchemaGroupRef) {
}
}
The other thing to bear in mind is that elements can be either abstract or concrete. Again, the JavaDocs are the best guidance.

Many of the solutions for validating XML in java use the JAXB API. There's an extensive tutorial available here. The basic recipe for doing what you're looking for with JAXB is as follows:
Obtain or create the XML schema to validate against.
Generate Java classes to bind the XML to using xjc, the JAXB compiler.
Write java code to:
Open the XML content as an input stream.
Create a JAXBContext and Unmarshaller
Pass the input stream to the Unmarshaller's unmarshal method.
The parts of the tutorial you can read for this are:
Hello, world
Unmarshalling XML

I see you have tried Eclipse XSD. Have you tried Eclipse Modeling Framework (EMF)? You can:
Generating an EMF Model using XML Schema (XSD)
Create a dynamic instance from your metamodel (3.1 With the dynamic instance creation tool)
This is for exploring the xsd. You can create the dynamic instance of the root element then you can right click the element and create child element. There you will see what the possible children element and so on.
As for saving the created EMF model to an xml complied xsd: I have to look it up. I think you can use JAXB for that (How to use EMF to read XML file?).
Some refs:
EMF: Eclipse Modeling Framework, 2nd Edition (written by creators)
Eclipse Modeling Framework (EMF)
Discover the Eclipse Modeling Framework (EMF) and Its Dynamic Capabilities
Creating Dynamic EMF Models From XSDs and Loading its Instances From XML as SDOs

This is a fairly complete sample on how to parse an XSD using XSOM:
import java.io.File;
import java.util.Iterator;
import java.util.Vector;
import org.xml.sax.ErrorHandler;
import com.sun.xml.xsom.XSComplexType;
import com.sun.xml.xsom.XSElementDecl;
import com.sun.xml.xsom.XSFacet;
import com.sun.xml.xsom.XSModelGroup;
import com.sun.xml.xsom.XSModelGroupDecl;
import com.sun.xml.xsom.XSParticle;
import com.sun.xml.xsom.XSRestrictionSimpleType;
import com.sun.xml.xsom.XSSchema;
import com.sun.xml.xsom.XSSchemaSet;
import com.sun.xml.xsom.XSSimpleType;
import com.sun.xml.xsom.XSTerm;
import com.sun.xml.xsom.impl.Const;
import com.sun.xml.xsom.parser.XSOMParser;
import com.sun.xml.xsom.util.DomAnnotationParserFactory;
public class XSOMNavigator
{
public static class SimpleTypeRestriction
{
public String[] enumeration = null;
public String maxValue = null;
public String minValue = null;
public String length = null;
public String maxLength = null;
public String minLength = null;
public String[] pattern = null;
public String totalDigits = null;
public String fractionDigits = null;
public String whiteSpace = null;
public String toString()
{
String enumValues = "";
if (enumeration != null)
{
for(String val : enumeration)
{
enumValues += val + ", ";
}
enumValues = enumValues.substring(0, enumValues.lastIndexOf(','));
}
String patternValues = "";
if (pattern != null)
{
for(String val : pattern)
{
patternValues += "(" + val + ")|";
}
patternValues = patternValues.substring(0, patternValues.lastIndexOf('|'));
}
String retval = "";
retval += minValue == null ? "" : "[MinValue = " + minValue + "]\t";
retval += maxValue == null ? "" : "[MaxValue = " + maxValue + "]\t";
retval += minLength == null ? "" : "[MinLength = " + minLength + "]\t";
retval += maxLength == null ? "" : "[MaxLength = " + maxLength + "]\t";
retval += pattern == null ? "" : "[Pattern(s) = " + patternValues + "]\t";
retval += totalDigits == null ? "" : "[TotalDigits = " + totalDigits + "]\t";
retval += fractionDigits == null ? "" : "[FractionDigits = " + fractionDigits + "]\t";
retval += whiteSpace == null ? "" : "[WhiteSpace = " + whiteSpace + "]\t";
retval += length == null ? "" : "[Length = " + length + "]\t";
retval += enumeration == null ? "" : "[Enumeration Values = " + enumValues + "]\t";
return retval;
}
}
private static void initRestrictions(XSSimpleType xsSimpleType, SimpleTypeRestriction simpleTypeRestriction)
{
XSRestrictionSimpleType restriction = xsSimpleType.asRestriction();
if (restriction != null)
{
Vector<String> enumeration = new Vector<String>();
Vector<String> pattern = new Vector<String>();
for (XSFacet facet : restriction.getDeclaredFacets())
{
if (facet.getName().equals(XSFacet.FACET_ENUMERATION))
{
enumeration.add(facet.getValue().value);
}
if (facet.getName().equals(XSFacet.FACET_MAXINCLUSIVE))
{
simpleTypeRestriction.maxValue = facet.getValue().value;
}
if (facet.getName().equals(XSFacet.FACET_MININCLUSIVE))
{
simpleTypeRestriction.minValue = facet.getValue().value;
}
if (facet.getName().equals(XSFacet.FACET_MAXEXCLUSIVE))
{
simpleTypeRestriction.maxValue = String.valueOf(Integer.parseInt(facet.getValue().value) - 1);
}
if (facet.getName().equals(XSFacet.FACET_MINEXCLUSIVE))
{
simpleTypeRestriction.minValue = String.valueOf(Integer.parseInt(facet.getValue().value) + 1);
}
if (facet.getName().equals(XSFacet.FACET_LENGTH))
{
simpleTypeRestriction.length = facet.getValue().value;
}
if (facet.getName().equals(XSFacet.FACET_MAXLENGTH))
{
simpleTypeRestriction.maxLength = facet.getValue().value;
}
if (facet.getName().equals(XSFacet.FACET_MINLENGTH))
{
simpleTypeRestriction.minLength = facet.getValue().value;
}
if (facet.getName().equals(XSFacet.FACET_PATTERN))
{
pattern.add(facet.getValue().value);
}
if (facet.getName().equals(XSFacet.FACET_TOTALDIGITS))
{
simpleTypeRestriction.totalDigits = facet.getValue().value;
}
if (facet.getName().equals(XSFacet.FACET_FRACTIONDIGITS))
{
simpleTypeRestriction.fractionDigits = facet.getValue().value;
}
if (facet.getName().equals(XSFacet.FACET_WHITESPACE))
{
simpleTypeRestriction.whiteSpace = facet.getValue().value;
}
}
if (enumeration.size() > 0)
{
simpleTypeRestriction.enumeration = enumeration.toArray(new String[] {});
}
if (pattern.size() > 0)
{
simpleTypeRestriction.pattern = pattern.toArray(new String[] {});
}
}
}
private static void printParticle(XSParticle particle, String occurs, String absPath, String indent)
{
boolean repeats = particle.isRepeated();
occurs = " MinOccurs = " + particle.getMinOccurs() + ", MaxOccurs = " + particle.getMaxOccurs() + ", Repeats = " + Boolean.toString(repeats);
XSTerm term = particle.getTerm();
if (term.isModelGroup())
{
printGroup(term.asModelGroup(), occurs, absPath, indent);
}
else if(term.isModelGroupDecl())
{
printGroupDecl(term.asModelGroupDecl(), occurs, absPath, indent);
}
else if (term.isElementDecl())
{
printElement(term.asElementDecl(), occurs, absPath, indent);
}
}
private static void printGroup(XSModelGroup modelGroup, String occurs, String absPath, String indent)
{
System.out.println(indent + "[Start of Group " + modelGroup.getCompositor() + occurs + "]" );
for (XSParticle particle : modelGroup.getChildren())
{
printParticle(particle, occurs, absPath, indent + "\t");
}
System.out.println(indent + "[End of Group " + modelGroup.getCompositor() + "]");
}
private static void printGroupDecl(XSModelGroupDecl modelGroupDecl, String occurs, String absPath, String indent)
{
System.out.println(indent + "[GroupDecl " + modelGroupDecl.getName() + occurs + "]");
printGroup(modelGroupDecl.getModelGroup(), occurs, absPath, indent);
}
private static void printComplexType(XSComplexType complexType, String occurs, String absPath, String indent)
{
System.out.println();
XSParticle particle = complexType.getContentType().asParticle();
if (particle != null)
{
printParticle(particle, occurs, absPath, indent);
}
}
private static void printSimpleType(XSSimpleType simpleType, String occurs, String absPath, String indent)
{
SimpleTypeRestriction restriction = new SimpleTypeRestriction();
initRestrictions(simpleType, restriction);
System.out.println(restriction.toString());
}
public static void printElement(XSElementDecl element, String occurs, String absPath, String indent)
{
absPath += "/" + element.getName();
String typeName = element.getType().getBaseType().getName();
if(element.getType().isSimpleType() && element.getType().asSimpleType().isPrimitive())
{
// We have a primitive type - So use that instead
typeName = element.getType().asSimpleType().getPrimitiveType().getName();
}
boolean nillable = element.isNillable();
System.out.print(indent + "[Element " + absPath + " " + occurs + "] of type [" + typeName + "]" + (nillable ? " [nillable] " : ""));
if (element.getType().isComplexType())
{
printComplexType(element.getType().asComplexType(), occurs, absPath, indent);
}
else
{
printSimpleType(element.getType().asSimpleType(), occurs, absPath, indent);
}
}
public static void printNameSpace(XSSchema s, String indent)
{
String nameSpace = s.getTargetNamespace();
// We do not want the default XSD namespaces or a namespace with nothing in it
if(nameSpace == null || Const.schemaNamespace.equals(nameSpace) || s.getElementDecls().isEmpty())
{
return;
}
System.out.println("Target namespace: " + nameSpace);
Iterator<XSElementDecl> jtr = s.iterateElementDecls();
while (jtr.hasNext())
{
XSElementDecl e = (XSElementDecl) jtr.next();
String occurs = "";
String absPath = "";
XSOMNavigator.printElement(e, occurs, absPath,indent);
System.out.println();
}
}
public static void xsomNavigate(File xsdFile)
{
ErrorHandler errorHandler = new ErrorReporter(System.err);
XSSchemaSet schemaSet = null;
XSOMParser parser = new XSOMParser();
try
{
parser.setErrorHandler(errorHandler);
parser.setAnnotationParser(new DomAnnotationParserFactory());
parser.parse(xsdFile);
schemaSet = parser.getResult();
}
catch (Exception exp)
{
exp.printStackTrace(System.out);
}
if(schemaSet != null)
{
// iterate each XSSchema object. XSSchema is a per-namespace schema.
Iterator<XSSchema> itr = schemaSet.iterateSchema();
while (itr.hasNext())
{
XSSchema s = (XSSchema) itr.next();
String indent = "";
printNameSpace(s, indent);
}
}
}
public static void printFile(String fileName)
{
File fileToParse = new File(fileName);
if (fileToParse != null && fileToParse.canRead())
{
xsomNavigate(fileToParse);
}
}
}
And for your Error Reporter use:
import java.io.OutputStream;
import java.io.PrintStream;
import java.text.MessageFormat;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
public class ErrorReporter implements ErrorHandler {
private final PrintStream out;
public ErrorReporter( PrintStream o ) { this.out = o; }
public ErrorReporter( OutputStream o ) { this(new PrintStream(o)); }
public void warning(SAXParseException e) throws SAXException {
print("[Warning]",e);
}
public void error(SAXParseException e) throws SAXException {
print("[Error ]",e);
}
public void fatalError(SAXParseException e) throws SAXException {
print("[Fatal ]",e);
}
private void print( String header, SAXParseException e ) {
out.println(header+' '+e.getMessage());
out.println(MessageFormat.format(" line {0} at {1}",
new Object[]{
Integer.toString(e.getLineNumber()),
e.getSystemId()}));
}
}
For your main use:
public class WDXSOMParser
{
public static void main(String[] args)
{
String fileName = null;
if(args != null && args.length > 0 && args[0] != null)
fileName = args[0];
else
fileName = "C:\\xml\\CollectionComments\\CollectionComment1.07.xsd";
//fileName = "C:\\xml\\PropertyListingContractSaleInfo\\PropertyListingContractSaleInfo.xsd";
//fileName = "C:\\xml\\PropertyPreservation\\PropertyPreservation.xsd";
XSOMNavigator.printFile(fileName);
}
}

It's agood bit of work depending on how compex your xsd is but basically.
if you had
<Document>
<Header/>
<Body/>
<Document>
And you wanted to find out where were the alowable children of header you'd (taking account of namespaces)
Xpath would have you look for '/element[name="Document"]/element[name="Header"]'
After that it depends on how much you want to do. You might find it easier to write or find something that loads an xsd into a DOM type structure.
Course you are going to possibly find all sorts of things under that elment in xsd, choice, sequence, any, attributes, complexType, SimpleContent, annotation.
Loads of time consuming fun.

Have a look at this.
How to parse schema using XOM Parser.
Also, here is the project home for XOM

How to use Java String variables inside XPath query

I have books.xml file which contains author name and book titles. I am using the following code snippet to query books.xml.
XPathFactory factory = XPathFactory.newInstance();
XPath xpath = factory.newXPath();
XPathExpression expr
= xpath.compile("//book[author= 'Larry Niven']/title/text()");
Now instead of directly putting the name in the query if I want to pass it while the program is running as a String variable how to do it. Just putting the string variable name is not working!

The problem here is when you have an author like the infamous Larry "Basher" O'Niven.
In this case, you will need to escape the variable, as in this naive implementation:
public static String escape(String s) {
Matcher matcher = Pattern.compile("['\"]")
.matcher(s);
StringBuilder buffer = new StringBuilder("concat(");
int start = 0;
while (matcher.find()) {
buffer.append("'")
.append(s.substring(start, matcher.start()))
.append("',");
buffer.append("'".equals(matcher.group()) ? "\"'\"," : "'\"',");
start = matcher.end();
}
if (start == 0) {
return "'" + s + "'";
}
return buffer.append("'")
.append(s.substring(start))
.append("'")
.append(")")
.toString();
}
This can be demonstrated with this code:
String xml =
"<xml><foo bar=\"Larry "Basher" O'Niven\">Ringworm</foo></xml>";
String query =
String.format("//foo[#bar=%s]", escape("Larry \"Basher\" O'Niven"));
System.out.println(query);
String book = XPathFactory.newInstance()
.newXPath()
.evaluate(query, new InputSource(new StringReader(xml)));
System.out.println(query + " > " + book);

You can in fact use both custom functions and variables in XPath -but a quick hack might be more productive for many uses.
Below is some code I developed as a learning tool for our students. It lets you do this:
// create some variable we want to use in the xpath
xPathVariableAndFunctionResolver.newVariable("myNamespace", "id", "xs:string", "l2"); // myNamespace is declared in the namespace context with prefix 'my'
// create an XPath expression
String expression = "//did:Component[#id=$my:id]"; // variable $namespace:name
XPathExpression findComponents = xPathFunctionAndVariableOperator.compile(expression);
// execute the XPath expression against the document
NodeList statements = (NodeList)findComponents.evaluate(document, XPathConstants.NODESET);
And much the same with XPath functions. The code, first a wrapper for the normal XPath evalutation:
public class XPathOperator {
protected XPath xPath;
protected XPathFactory xPathFactory;
private Hashtable<String, XPathExpression> compiled = new Hashtable<String, XPathExpression>();
protected void initFactory() throws XPathFactoryConfigurationException {
xPathFactory = XPathFactory.newInstance(XPathConstants.DOM_OBJECT_MODEL);
}
protected void initXPath(NamespaceContext context) {
xPath = xPathFactory.newXPath();
xPath.setNamespaceContext(context);
}
public XPathOperator(NamespaceContext context) throws XPathFactoryConfigurationException {
initFactory();
initXPath(context);
}
public Object evaluate(Document document, String expression, QName value) throws XPathExpressionException {
// create an XPath expression - http://www.zvon.org/xxl/XPathTutorial/General/examples.html
XPathExpression findStatements = compile(expression);
// execute the XPath expression against the document
return (NodeList)findStatements.evaluate(document, value);
}
public XPathExpression compile(String expression) throws XPathExpressionException {
if(compiled.containsKey(expression)) {
return (XPathExpression) compiled.get(expression);
}
XPathExpression xpath = xPath.compile(expression);
System.out.println("Compiled XPath " + expression);
compiled.put(expression, xpath);
return xpath;
}
}
Then we add the concept of custom variables and functions, of course with namespaces:
public class XPathFunctionAndVariableOperator extends XPathOperator {
public XPathFunctionAndVariableOperator(NamespaceContext context, XPathVariableResolver xPathVariableResolver, XPathFunctionResolver xPathFunctionResolver) throws XPathFactoryConfigurationException {
super(context);
xPath.setXPathVariableResolver(xPathVariableResolver);
xPath.setXPathFunctionResolver(xPathFunctionResolver);
}
}
Which would not be much fun without the variable and function resolvers:
public class XPathVariableAndFunctionResolver implements XPathVariableResolver, XPathFunctionResolver {
private Hashtable functions = new Hashtable();
private Hashtable variables = new Hashtable();
private SchemaDVFactory factory = SchemaDVFactory.getInstance();
public XPathFunction resolveFunction(QName functionName, int arity) {
Hashtable table = (Hashtable)functions.get(functionName.getNamespaceURI());
if(table != null) {
XPathFunction function = (XPathFunction)table.get(functionName.getLocalPart());
if(function == null) {
throw new RuntimeException("Function " + functionName.getLocalPart() + " does not exist in namespace " + functionName.getNamespaceURI() + "!");
}
System.out.println("Resolved function " + functionName + " with " + arity + " argument(s)");
return function;
}
throw new RuntimeException("Function namespace " + functionName.getNamespaceURI() + " does not exist!");
}
/**
*
* Adds a variable using namespace and name, primitive type and default value
*
* #param namespace
* #param name
* #param datatype one of the built-in XML datatypes
* #param value
* #throws InvalidDatatypeValueException if value is not of correct datatype
*/
#SuppressWarnings("unchecked")
public void newVariable(String namespace, String name, String datatype, String value) throws InvalidDatatypeValueException {
int index = datatype.indexOf(":");
if(index != -1) {
datatype = datatype.substring(index+1);
}
XSSimpleType builtInType = factory.getBuiltInType(datatype);
if(builtInType == null) {
throw new RuntimeException("Null type for " + datatype);
}
ValidationState validationState = new ValidationState();
ValidatedInfo validatedInfo = new ValidatedInfo();
builtInType.validate(value, validationState, validatedInfo);
System.out.println("Defined variable " + name + " as " + datatype + " with value " + value);
Hashtable table;
if(!variables.containsKey(namespace)) {
table = new Hashtable();
variables.put(namespace, table);
} else {
table = (Hashtable)variables.get(namespace);
}
table.put(name, new Object[]{validatedInfo, builtInType});
}
public void newVariableValue(String namespace, String name, String value) throws InvalidDatatypeValueException {
ValidationState validationState = new ValidationState();
Hashtable table;
if(!variables.containsKey(namespace)) {
throw new RuntimeException("Unknown variable namespace " + namespace);
} else {
table = (Hashtable)variables.get(namespace);
}
Object[] bundle = (Object[])table.get(name);
ValidatedInfo validatedInfo = (ValidatedInfo)bundle[0];
XSSimpleType builtInType = (XSSimpleType)bundle[1];
builtInType.validate(value, validationState, validatedInfo); // direct reference transfer of value
System.out.println("Assigned value " + validatedInfo.normalizedValue + " to variable " + name);
}
public Object resolveVariable(QName variableName) {
Hashtable table;
if(!variables.containsKey(variableName.getNamespaceURI())) {
throw new RuntimeException("Unknown variable namespace " + variableName.getNamespaceURI());
} else {
table = (Hashtable)variables.get(variableName.getNamespaceURI());
}
Object[] bundle = (Object[])table.get(variableName.getLocalPart());
if(bundle != null) {
ValidatedInfo var = (ValidatedInfo)bundle[0];
if(var != null) {
switch(var.actualValueType) { // some types omitted, customize your own
case XSConstants.INTEGER_DT:
case XSConstants.DECIMAL_DT:
case XSConstants.INT_DT:
case XSConstants.LONG_DT:
case XSConstants.SHORT_DT:
case XSConstants.BYTE_DT:
case XSConstants.UNSIGNEDBYTE_DT:
case XSConstants.UNSIGNEDINT_DT:
case XSConstants.UNSIGNEDLONG_DT:
case XSConstants.UNSIGNEDSHORT_DT:
return new Integer(var.normalizedValue);
case XSConstants.DATE_DT:
case XSConstants.DATETIME_DT:
case XSConstants.GDAY_DT:
case XSConstants.GMONTH_DT:
case XSConstants.GMONTHDAY_DT:
case XSConstants.GYEAR_DT:
case XSConstants.GYEARMONTH_DT:
case XSConstants.DURATION_DT:
case XSConstants.TIME_DT:
return new Date(var.normalizedValue);
case XSConstants.FLOAT_DT:
return new Float(Float.parseFloat(var.normalizedValue));
case XSConstants.DOUBLE_DT:
return new Double(Double.parseDouble(var.normalizedValue));
case XSConstants.STRING_DT:
case XSConstants.QNAME_DT:
return var.normalizedValue;
default:
throw new RuntimeException("Unknown datatype " + var.actualValueType + " for variable " + variableName + " in namespace " + variableName.getNamespaceURI());
}
}
}
throw new RuntimeException("Could not resolve value " + variableName + " in namespace " + variableName.getNamespaceURI());
}
public void addFunction(String namespace, String name, XPathFunction function) {
Hashtable table;
if(!functions.containsKey(namespace)) {
table = new Hashtable();
functions.put(namespace, table);
} else {
table = (Hashtable)functions.get(namespace);
}
table.put(name, function);
}
}
The functions obviously cannot be contained within the above, since typically running custom code (i.e. the whole point is that you write your own class), so go with something like
public abstract class XPathFunctionImpl implements XPathFunction {
/**
* This function is called by the XPath expression as it implements the interface XPathFunction
*/
protected int numberArguments;
public Object evaluate(List args) throws XPathFunctionException {
if(args.size() == numberArguments) {
return evaluateImpl(args);
}
throw new RuntimeException("Illegal number of arguments for " + this);
}
public abstract Object evaluateImpl(List args) throws XPathFunctionException;
}
And then the implement/subclass your own logic in evaluateImpl(..) somehow.
This sure makes the String appending seem quite ... attractive ;) Note: This code is several years old and there might exist a better way of doing all this.

If you want a ready-made implementation you can use commons JXPath which supports declaration of variables:
http://commons.apache.org/jxpath/users-guide.html#Variables

String rawXPath = "//book[author= '" + larrysName + "']/title/text()";
or
String rawXPath = String.format("//book[author= '%s']/title/text()", larrysName);
where larrysName is a variable of type String coming from somewhere.

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