/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.tuscany.sca.common.xml.stax.reader;
import java.util.ArrayList;
import java.util.EmptyStackException;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.xml.namespace.NamespaceContext;
/**
* @version $Rev: 806026 $ $Date: 2009-08-20 03:58:09 +0100 (Thu, 20 Aug 2009) $
*/
public class XmlNodeIterator implements Iterator<XmlNode> {
public static final int START = 0;
public static final int END = 1;
protected FastStack<ElementHolder> stack;
protected int state;
protected NamespaceContextImpl nsContext;
public XmlNodeIterator(XmlNode rootNode) {
super();
List<XmlNode> v = new ArrayList<XmlNode>(1);
v.add(rootNode);
stack = new FastStack<ElementHolder>();
Iterator<XmlNode> i = v.iterator();
stack.push(new ElementHolder(null, i));
this.state = START;
this.nsContext = new NamespaceContextImpl(null);
}
public boolean hasNext() {
return !(stack.empty() || (state == END && stack.peek().parent == null));
}
public XmlNode next() {
this.state = START;
ElementHolder element = stack.peek();
Iterator<XmlNode> it = element.children;
if (it == null || (!it.hasNext())) {
// End of the children, return END event of parent
stack.pop();
this.state = END;
this.nsContext = (NamespaceContextImpl)nsContext.getParent();
return element.parent;
}
XmlNode node = it.next();
stack.push(new ElementHolder(node, node.children()));
this.nsContext = new NamespaceContextImpl(this.nsContext);
populateNamespaces(node);
return node;
}
public void remove() {
throw new UnsupportedOperationException();
}
public int getState() {
return state;
}
public NamespaceContext getNamespaceContext() {
return nsContext;
}
private void populateNamespaces(XmlNode element) {
if (element.getName() != null) {
if (element.namespaces() != null) {
for (Map.Entry<String, String> e : element.namespaces().entrySet()) {
nsContext.register(e.getKey(), e.getValue());
}
}
}
}
private static class ElementHolder {
private XmlNode parent;
private Iterator<XmlNode> children;
public ElementHolder(XmlNode parent, Iterator<XmlNode> children) {
this.parent = parent;
this.children = children;
}
}
/**
* An implementation of the {@link java.util.Stack} API that is based on an <code>ArrayList</code> instead of a
* <code>Vector</code>, so it is not synchronized to protect against multi-threaded access. The implementation is
* therefore operates faster in environments where you do not need to worry about multiple thread contention.
* <p>
* The removal order of an <code>ArrayStack</code> is based on insertion order: The most recently added element is
* removed first. The iteration order is <i>not</i> the same as the removal order. The iterator returns elements
* from the bottom up, whereas the {@link #remove()} method removes them from the top down.
* <p>
* Unlike <code>Stack</code>, <code>ArrayStack</code> accepts null entries.
*/
public static class FastStack<T> extends ArrayList<T> {
/** Ensure Serialization compatibility */
private static final long serialVersionUID = 2130079159931574599L;
/**
* Constructs a new empty <code>ArrayStack</code>. The initial size is controlled by <code>ArrayList</code>
* and is currently 10.
*/
public FastStack() {
super();
}
/**
* Constructs a new empty <code>ArrayStack</code> with an initial size.
*
* @param initialSize the initial size to use
* @throws IllegalArgumentException if the specified initial size is negative
*/
public FastStack(int initialSize) {
super(initialSize);
}
/**
* Return <code>true</code> if this stack is currently empty.
* <p>
* This method exists for compatibility with <code>java.util.Stack</code>. New users of this class should use
* <code>isEmpty</code> instead.
*
* @return true if the stack is currently empty
*/
public boolean empty() {
return isEmpty();
}
/**
* Returns the top item off of this stack without removing it.
*
* @return the top item on the stack
* @throws EmptyStackException if the stack is empty
*/
public T peek() throws EmptyStackException {
int n = size();
if (n <= 0) {
throw new EmptyStackException();
} else {
return get(n - 1);
}
}
/**
* Returns the n'th item down (zero-relative) from the top of this stack without removing it.
*
* @param n the number of items down to go
* @return the n'th item on the stack, zero relative
* @throws EmptyStackException if there are not enough items on the stack to satisfy this request
*/
public T peek(int n) throws EmptyStackException {
int m = (size() - n) - 1;
if (m < 0) {
throw new EmptyStackException();
} else {
return get(m);
}
}
/**
* Pops the top item off of this stack and return it.
*
* @return the top item on the stack
* @throws EmptyStackException if the stack is empty
*/
public T pop() throws EmptyStackException {
int n = size();
if (n <= 0) {
throw new EmptyStackException();
} else {
return remove(n - 1);
}
}
/**
* Pushes a new item onto the top of this stack. The pushed item is also returned. This is equivalent to calling
* <code>add</code>.
*
* @param item the item to be added
* @return the item just pushed
*/
public Object push(T item) {
add(item);
return item;
}
/**
* Returns the top-most index for the object in the stack
*
* @param object the object to be searched for
* @return top-most index, or -1 if not found
*/
public int search(T object) {
int i = size() - 1; // Current index
while (i >= 0) {
T current = get(i);
if ((object == null && current == null) || (object != null && object.equals(current))) {
return i;
}
i--;
}
return -1;
}
/**
* Returns the element on the top of the stack.
*
* @return the element on the top of the stack
* @throws EmptyStackException if the stack is empty
*/
public T get() {
int size = size();
if (size == 0) {
throw new EmptyStackException();
}
return get(size - 1);
}
/**
* Removes the element on the top of the stack.
*
* @return the removed element
* @throws EmptyStackException if the stack is empty
*/
public T remove() {
int size = size();
if (size == 0) {
throw new EmptyStackException();
}
return remove(size - 1);
}
}
}