/** Creates an expr, handling some special cases. */
public static Expr create(AbstractPattern pattern) {
if (pattern instanceof NodeTypePattern
&& pattern.getParent() instanceof FromSelf
&& pattern.toString().equals(".")) return new ObjectExpr(SELF, ".");
else if (pattern instanceof FromContext
&& ((FromContext) pattern).getCount() == 0
&& pattern.getParent() == null) return new ObjectExpr(SELF, ".");
else if (pattern instanceof NodePattern
&& pattern.getParent() instanceof FromAttributes
&& pattern.getParent().getParent() instanceof FromContext
&& ((FromContext) pattern.getParent().getParent()).getCount() == 0)
return new ObjectExpr(ATTRIBUTE, ((NodePattern) pattern).getNodeName());
else return new NodeSetExpr(pattern);
}
/**
* Returns the value of the expression as a number.
*
* @param node the current node
* @param env the variable environment.
*/
public double evalNumber(Node node, ExprEnvironment env) throws XPathException {
Node value = _pattern.findAny(node, env);
if (value == null) return Double.NaN;
String string = XmlUtil.textValue(value);
return stringToNumber(string);
}
/**
* Evaluate a node-set object, returning an ArrayList of the node set.
*
* @param node the current node
* @param env the variable environment
* @return an array list of the nodes
*/
public Object evalObject(Node node, ExprEnvironment env) throws XPathException {
NodeListImpl list = new NodeListImpl();
NodeIterator iter = _pattern.select(node, env);
Node value = null;
while ((value = iter.nextNode()) != null) list.add(value);
return list;
}
/**
* Returns true if there are any patterns matching the pattern.
*
* @param node the current node
* @param env the variable environment.
*/
public boolean evalBoolean(Node node, ExprEnvironment env) throws XPathException {
return _pattern.findAny(node, env) != null;
}
public String toString() {
return _pattern.toString();
}
public boolean equals(Object b) {
if (!(b instanceof NodeSetExpr)) return false;
return _pattern.equals(((NodeSetExpr) b)._pattern);
}
/**
* Evaluate a node-set object, returning an iterator of the node set.
*
* @param node the current node
* @param env the variable environment
* @return an iterator of the nodes
*/
public NodeIterator evalNodeSet(Node node, ExprEnvironment env) throws XPathException {
return _pattern.select(node, env);
}
/**
* Returns the value of the node set expression as a string. The value is the text value of the
* first node.
*
* @param node the current node
* @param env the variable environment
* @return the combined text value of the node.
*/
public String evalString(Node node, ExprEnvironment env) throws XPathException {
Node value = _pattern.findAny(node, env);
if (value == null) return "";
else return XmlUtil.textValue(value);
}
