/*
* © Copyright IBM Corp. 2012
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package com.ibm.commons.xml;
import java.util.Iterator;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import com.ibm.commons.xml.xpath.NodeListImpl;
import com.ibm.commons.xml.xpath.XPathException;
import com.ibm.commons.xml.xpath.XPathExpression;
/**
* XPath context associated to an XML document.
*/
public class XPathContext {
private Document _doc;
private XPathContext _parent;
private XPathExpression _xPathExpression;
private NodeListImpl _contextNodes;
private boolean _isAbsolute;
private Node _filteredContextNodes;
public XPathContext(Document doc, XPathContext parent, String path) throws XMLException {
_doc = doc;
_parent = parent;
_xPathExpression = DOMUtil.createXPath(path);
_isAbsolute = _xPathExpression.isFromRoot();
compute();
}
public Document getDocument() {
return _doc;
}
public String getExpression() {
return _xPathExpression.getExpression();
}
public void compute() throws XPathException {
// compute the result of this xpath against the parent results, or the main document
XResult r = null;
if(!_isAbsolute && _parent!=null) {
NodeListImpl parentNodes = _parent._contextNodes;
if (parentNodes == null) {
return;
}
r = _xPathExpression.eval(parentNodes, null);
}
else {
if (_doc.getDocumentElement() == null) {
return;
}
r = _xPathExpression.eval(_doc, null);
}
// and fill the current nodes
for( Iterator it=r.getNodeIterator(); it.hasNext(); ) {
if(_contextNodes==null) {
_contextNodes = new NodeListImpl();
}
_contextNodes.add(it.next());
}
}
public XPathContext getParent() {
return _parent;
}
public Object getContextNodes() {
if (_filteredContextNodes!=null) {
return _filteredContextNodes;
}
return _contextNodes;
}
public int getContextNodesLength() {
return (_contextNodes == null) ? 0 : _contextNodes.getLength();
}
public void setFilterIndex(int index) throws XMLException {
if(index<0) {
this._filteredContextNodes = null;
} else {
index--; // Make it zero based
if(index<0) {
throw new XMLException(null,"XPath indexes start at 1"); // $NLS-XPathContext.XPathindexesstartat1-1$
}
if(_contextNodes==null) {
throw new XMLException(null,"Invalid XPath context: context is empty"); // $NLS-XPathContext.InvalidXPathcontextcontextisempty-1$
}
if(index>=_contextNodes.getLength()) {
throw new XMLException(null,"Invalid XPath context: index {0} too big",Integer.toString(index)); // $NLS-XPathContext.InvalidXPathcontextindex0toobig-1$
}
this._filteredContextNodes = _contextNodes.item(index);
}
}
public void setFilterNode(Node node) {
this._filteredContextNodes = node;
}
public Node getUniqueContextNode() throws XMLException {
if(_filteredContextNodes!=null) {
return _filteredContextNodes;
}
if(_contextNodes==null) {
throw new XMLException(null,"Invalid XPath context: context is empty"); // $NLS-XPathContext.InvalidXPathcontextcontextisempty.1-1$
}
if(_contextNodes.getLength()>1) {
throw new XMLException(null,"Invalid XPath context: context contains more than one node"); // $NLS-XPathContext.InvalidXPathcontextcontextcontain-1$
}
return _contextNodes.item(0);
}
public void createNodes() throws XMLException {
if(_contextNodes==null) {
Node ctx = _doc;
// Ensure that the parent is created
// Uniquely if we are not absolute
if(!_isAbsolute && _parent!=null) {
_parent.createNodes();
ctx = _parent.getUniqueContextNode();
}
// And evaluate the XPath
Object o = _xPathExpression.createNodes(ctx, null);
if(o!=null) {
_contextNodes = new NodeListImpl();
_contextNodes.add(o);
}
}
}
}