package net.sf.saxon.dotnet;
import cli.System.Collections.IEnumerable;
import cli.System.Collections.IEnumerator;
import cli.System.Uri;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.functions.ResolveURI;
import net.sf.saxon.functions.StandardCollectionURIResolver;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.SequenceIterator;
import net.sf.saxon.trans.Err;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.value.AnyURIValue;
import net.sf.saxon.value.StringValue;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.HashMap;
/**
* This class implements the CollectionURIResolver interface by wrapping an IEnumerable which
* returns Uri values (the URIs of the documents in the collection)
*/
public class DotNetCollectionURIResolver extends StandardCollectionURIResolver {
private HashMap<String, IEnumerable> registeredCollections = new HashMap<String, IEnumerable>(20);
public DotNetCollectionURIResolver() {}
public void registerCollection(String uri, IEnumerable enumerable) {
if (enumerable == null) {
registeredCollections.remove(uri);
} else if (uri == null) {
registeredCollections.put("", enumerable);
} else {
registeredCollections.put(uri, enumerable);
}
}
/**
* Resolve a URI.
*
* @param href The relative URI of the collection. This corresponds to the
* argument supplied to the collection() function. If the collection() function
* was called with no arguments (to get the "default collection") this argument
* will be null.
* @param base The base URI that should be used. This is the base URI of the
* static context in which the call to collection() was made, typically the URI
* of the stylesheet or query module
* @param context The dynamic execution context
* @return an Iterator over the documents in the collection. The items returned
* by this iterator must be instances either of xs:anyURI, or of node() (specifically,
* {@link net.sf.saxon.om.NodeInfo}.). If xs:anyURI values are returned, the corresponding
* document will be retrieved as if by a call to the doc() function: this means that
* the system first checks to see if the document is already loaded, and if not, calls
* the registered URIResolver to dereference the URI. This is the recommended approach
* to ensure that the resulting collection is stable: however, it has the consequence
* that the documents will by default remain in memory for the duration of the query
* or transformation.
* <p/>
* If the URI is not recognized, the method may either return an empty iterator,
* in which case no error is reported, or it may throw an exception, in which case
* the query or transformation fails. Returning null has the same effect as returning
* an empty iterator.
*/
public SequenceIterator resolve(String href, String base, XPathContext context) throws XPathException {
if (href == null) {
IEnumerable ie = registeredCollections.get("");
if (ie == null) {
return super.resolve(href, base, context);
}
return new UriIterator(ie);
}
URI relativeURI;
try {
relativeURI = new URI(ResolveURI.escapeSpaces(href));
} catch (URISyntaxException e) {
XPathException err = new XPathException("Invalid relative URI " + Err.wrap(href, Err.VALUE) +
" passed to collection() function");
err.setErrorCode("FODC0004");
err.setXPathContext(context);
throw err;
}
URI abs = makeAbsoluteURI(href, base, context, relativeURI);
IEnumerable ie = registeredCollections.get(abs.toString());
if (ie == null) {
return super.resolve(href, base, context);
}
return new UriIterator(ie);
}
private static class UriIterator implements SequenceIterator {
private IEnumerable enumerable;
private IEnumerator enumerator;
private StringValue current;
private int position = 0;
public UriIterator(IEnumerable enumerable) {
this.enumerable = enumerable;
this.enumerator = enumerable.GetEnumerator();
}
/**
* Get properties of this iterator, as a bit-significant integer.
*
* @return the properties of this iterator. This will be some combination of
* properties such as {@link #GROUNDED}, {@link #LAST_POSITION_FINDER},
* and {@link #LOOKAHEAD}. It is always
* acceptable to return the value zero, indicating that there are no known special properties.
* It is acceptable for the properties of the iterator to change depending on its state.
* @since 8.6
*/
public int getProperties() {
return 0;
}
/**
* Get the next item in the sequence. This method changes the state of the
* iterator, in particular it affects the result of subsequent calls of
* position() and current().
*
* @return the next item, or null if there are no more items. Once a call
* on next() has returned null, no further calls should be made. The preferred
* action for an iterator if subsequent calls on next() are made is to return
* null again, and all implementations within Saxon follow this rule.
* @throws net.sf.saxon.trans.XPathException
* if an error occurs retrieving the next item
* @since 8.4
*/
public Item next() throws XPathException {
if (enumerator.MoveNext()) {
Uri u = (Uri)enumerator.get_Current();
current = new AnyURIValue(u.ToString());
position++;
return current;
} else {
position = -1;
return null;
}
}
/**
* Get the current value in the sequence (the one returned by the
* most recent call on next()). This will be null before the first
* call of next(). This method does not change the state of the iterator.
*
* @return the current item, the one most recently returned by a call on
* next(). Returns null if next() has not been called, or if the end
* of the sequence has been reached.
* @since 8.4
*/
public Item current() {
return current;
}
/**
* Get the current position. This will usually be zero before the first call
* on next(), otherwise it will be the number of times that next() has
* been called. Once next() has returned null, the preferred action is
* for subsequent calls on position() to return -1, but not all existing
* implementations follow this practice. (In particular, the EmptyIterator
* is stateless, and always returns 0 as the value of position(), whether
* or not next() has been called.)
* <p/>
* This method does not change the state of the iterator.
*
* @return the current position, the position of the item returned by the
* most recent call of next(). This is 1 after next() has been successfully
* called once, 2 after it has been called twice, and so on. If next() has
* never been called, the method returns zero. If the end of the sequence
* has been reached, the value returned will always be <= 0; the preferred
* value is -1.
* @since 8.4
*/
public int position() {
return position;
}
public void close() {
}
/**
* Get another SequenceIterator that iterates over the same items as the original,
* but which is repositioned at the start of the sequence.
* <p/>
* This method allows access to all the items in the sequence without disturbing the
* current position of the iterator. Internally, its main use is in evaluating the last()
* function.
* <p/>
* This method does not change the state of the iterator.
*
* @return a SequenceIterator that iterates over the same items,
* positioned before the first item
* @throws net.sf.saxon.trans.XPathException
* if any error occurs
* @since 8.4
*/
public SequenceIterator getAnother() throws XPathException {
return new UriIterator(enumerable);
}
}
}
//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
// you may not use this file except in compliance with the License. You may obtain a copy of the
// License at http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Contributor(s):
//