package net.sf.saxon.functions;
import net.sf.saxon.Controller;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.ExpressionVisitor;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.om.DocumentInfo;
import net.sf.saxon.om.DocumentPool;
import net.sf.saxon.om.Item;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.value.AtomicValue;
import net.sf.saxon.value.BooleanValue;
import javax.xml.transform.ErrorListener;
import javax.xml.transform.TransformerException;
import java.net.URI;
import java.net.URISyntaxException;
/**
* Implement the fn:doc-available() function
*/
public class DocAvailable extends SystemFunction {
private String expressionBaseURI = null;
public void checkArguments(ExpressionVisitor visitor) throws XPathException {
if (expressionBaseURI == null) {
super.checkArguments(visitor);
expressionBaseURI = visitor.getStaticContext().getBaseURI();
}
}
/**
* Get the static base URI of the expression
*/
public String getStaticBaseURI() {
return expressionBaseURI;
}
/**
* preEvaluate: this method suppresses compile-time evaluation by doing nothing
* @param visitor an expression visitor
*/
public Expression preEvaluate(ExpressionVisitor visitor) {
return this;
}
/**
* Evaluate the expression
* @param context
* @return the result of evaluating the expression (a BooleanValue)
* @throws net.sf.saxon.trans.XPathException
*/
public Item evaluateItem(XPathContext context) throws XPathException {
AtomicValue hrefVal = (AtomicValue)argument[0].evaluateItem(context);
if (hrefVal==null) {
return BooleanValue.FALSE;
}
String href = hrefVal.getStringValue();
// suppress all error messages while attempting to fetch the document
Controller controller = context.getController();
ErrorListener old = controller.getErrorListener();
controller.setErrorListener(new ErrorListener() {
public void warning(TransformerException exception) {}
public void error(TransformerException exception) {}
public void fatalError(TransformerException exception) {}
});
try {
boolean b = docAvailable(href, context);
controller.setErrorListener(old);
return BooleanValue.get(b);
} catch (URISyntaxException err) {
controller.setErrorListener(old);
XPathException xe = new XPathException(err);
xe.setErrorCode("FODC0005");
xe.setXPathContext(context);
xe.setLocator(this);
throw xe;
}
}
private boolean docAvailable(String href, XPathContext context) throws URISyntaxException {
try {
String documentKey = Document.computeDocumentKey(href, expressionBaseURI, context);
DocumentPool pool = context.getController().getDocumentPool();
if (pool.isMarkedUnavailable(documentKey)) {
return false;
}
DocumentInfo doc = pool.find(documentKey);
if (doc != null) {
return true;
}
Item item = Document.makeDoc(href, expressionBaseURI, context, this);
if (item != null) {
return true;
} else {
// The document does not exist; ensure that this remains the case
pool.markUnavailable(documentKey);
return false;
}
} catch (Exception err) {
try {
new URI(href);
} catch (URISyntaxException e2) {
throw e2;
}
return false;
}
}
}
//
// 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.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//