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package com.sun.xml.xsom;
import com.sun.xml.xsom.impl.scd.Iterators;
import com.sun.xml.xsom.impl.scd.ParseException;
import com.sun.xml.xsom.impl.scd.SCDImpl;
import com.sun.xml.xsom.impl.scd.SCDParser;
import com.sun.xml.xsom.impl.scd.Step;
import com.sun.xml.xsom.impl.scd.TokenMgrError;
import com.sun.xml.xsom.util.DeferedCollection;
import javax.xml.namespace.NamespaceContext;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
/**
* Schema Component Designator (SCD).
*
* <p>
* SCD for schema is what XPath is for XML. SCD allows you to select a schema component(s)
* from a schema component(s).
*
* <p>
* See <a href="http://www.w3.org/TR/2005/WD-xmlschema-ref-20050329/">XML Schema: Component Designators</a>.
* This implementation is based on 03/29/2005 working draft.
*
* @author Kohsuke Kawaguchi
*/
public abstract class SCD {
/**
* Parses the string representation of SCD.
*
* <p>
* This method involves parsing the path expression and preparing the in-memory
* structure, so this is useful when you plan to use the same SCD against
* different context node multiple times.
*
* <p>
* If you want to evaluate SCD just once, use {@link XSComponent#select} methods.
*
* @param path
* the string representation of SCD, such as "/foo/bar".
* @param nsContext
* Its {@link NamespaceContext#getNamespaceURI(String)} is used
* to resolve prefixes in the SCD to the namespace URI.
*/
public static SCD create(String path, NamespaceContext nsContext) throws java.text.ParseException {
try {
SCDParser p = new SCDParser(path,nsContext);
List<?> list = p.RelativeSchemaComponentPath();
return new SCDImpl(path,list.toArray(new Step[list.size()]));
} catch (TokenMgrError e) {
throw setCause(new java.text.ParseException(e.getMessage(), -1 ),e);
} catch (ParseException e) {
throw setCause(new java.text.ParseException(e.getMessage(), e.currentToken.beginColumn ),e);
}
}
private static java.text.ParseException setCause(java.text.ParseException e, Throwable x) {
e.initCause(x);
return e;
}
/**
* Evaluates the SCD against the given context node and
* returns the matched nodes.
*
* @return
* could be empty but never be null.
*/
public final Collection<XSComponent> select(XSComponent contextNode) {
return new DeferedCollection<XSComponent>(select(Iterators.singleton(contextNode)));
}
/**
* Evaluates the SCD against the whole schema and
* returns the matched nodes.
*
* <p>
* This method is here because {@link XSSchemaSet}
* doesn't implement {@link XSComponent}.
*
* @return
* could be empty but never be null.
*/
public final Collection<XSComponent> select(XSSchemaSet contextNode) {
return select(contextNode.getSchemas());
}
/**
* Evaluates the SCD against the given context node and
* returns the matched node.
*
* @return
* null if the SCD didn't match anything. If the SCD matched more than one node,
* the first one will be returned.
*/
public final XSComponent selectSingle(XSComponent contextNode) {
Iterator<XSComponent> r = select(Iterators.singleton(contextNode));
if(r.hasNext()) return r.next();
return null;
}
/**
* Evaluates the SCD against the whole schema set and
* returns the matched node.
*
* @return
* null if the SCD didn't match anything. If the SCD matched more than one node,
* the first one will be returned.
*/
public final XSComponent selectSingle(XSSchemaSet contextNode) {
Iterator<XSComponent> r = select(contextNode.iterateSchema());
if(r.hasNext()) return r.next();
return null;
}
/**
* Evaluates the SCD against the given set of context nodes and
* returns the matched nodes.
*
* @param contextNodes
* {@link XSComponent}s that represent the context node against
* which {@link SCD} is evaluated.
*
* @return
* could be empty but never be null.
*/
public abstract Iterator<XSComponent> select(Iterator<? extends XSComponent> contextNodes);
/**
* Evaluates the SCD against the given set of context nodes and
* returns the matched nodes.
*
* @param contextNodes
* {@link XSComponent}s that represent the context node against
* which {@link SCD} is evaluated.
*
* @return
* could be empty but never be null.
*/
public final Collection<XSComponent> select(Collection<? extends XSComponent> contextNodes) {
return new DeferedCollection<XSComponent>(select(contextNodes.iterator()));
}
/**
* Returns the textual SCD representation as given to {@link SCD#create(String, NamespaceContext)}.
*/
public abstract String toString();
}