com.thoughtworks.xstream.io.xml.AbstractPullReader Maven / Gradle / Ivy
/*
* Copyright (C) 2005, 2006 Joe Walnes.
* Copyright (C) 2006, 2007 XStream Committers.
* All rights reserved.
*
* The software in this package is published under the terms of the BSD
* style license a copy of which has been included with this distribution in
* the LICENSE.txt file.
*
* Created on 24. April 2005 by Joe Walnes
*/
package com.thoughtworks.xstream.io.xml;
import java.util.Iterator;
import com.thoughtworks.xstream.core.util.FastStack;
import com.thoughtworks.xstream.io.AttributeNameIterator;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
/**
* Base class that contains common functionality across HierarchicalStreamReader implementations
* that need to read from a pull parser.
*
* @author Joe Walnes
* @author James Strachan
*/
public abstract class AbstractPullReader extends AbstractXmlReader {
protected static final int START_NODE = 1;
protected static final int END_NODE = 2;
protected static final int TEXT = 3;
protected static final int COMMENT = 4;
protected static final int OTHER = 0;
private final FastStack elementStack = new FastStack(16);
private final FastStack lookahead = new FastStack(4);
private final FastStack lookback = new FastStack(4);
private boolean marked;
private static class Event {
int type;
String value;
}
/**
* @since 1.2
*/
protected AbstractPullReader(XmlFriendlyReplacer replacer) {
super(replacer);
}
/**
* Pull the next event from the stream.
*
* This MUST return {@link #START_NODE}, {@link #END_NODE}, {@link #TEXT}, {@link #COMMENT},
* {@link #OTHER} or throw {@link com.thoughtworks.xstream.io.StreamException}.
*
* The underlying pull parser will most likely return its own event types. These must be
* mapped to the appropriate events.
*/
protected abstract int pullNextEvent();
/**
* Pull the name of the current element from the stream.
*/
protected abstract String pullElementName();
/**
* Pull the contents of the current text node from the stream.
*/
protected abstract String pullText();
public boolean hasMoreChildren() {
mark();
while (true) {
switch (readEvent().type) {
case START_NODE:
reset();
return true;
case END_NODE:
reset();
return false;
default:
continue;
}
}
}
public String peekNextChild() {
mark();
while (true) {
Event ev = readEvent();
switch (ev.type) {
case START_NODE:
reset();
return ev.value;
case END_NODE:
reset();
return null;
default:
continue;
}
}
}
public void moveDown() {
int currentDepth = elementStack.size();
while (elementStack.size() <= currentDepth) {
move();
if (elementStack.size() < currentDepth) {
throw new RuntimeException(); // sanity check
}
}
}
public void moveUp() {
int currentDepth = elementStack.size();
while (elementStack.size() >= currentDepth) {
move();
}
}
private void move() {
switch (readEvent().type) {
case START_NODE:
elementStack.push(pullElementName());
break;
case END_NODE:
elementStack.pop();
break;
}
}
private Event readEvent() {
if (marked) {
if (lookback.hasStuff()) {
return (Event) lookahead.push(lookback.pop());
} else {
return (Event) lookahead.push(readRealEvent());
}
} else {
if (lookback.hasStuff()) {
return (Event) lookback.pop();
} else {
return readRealEvent();
}
}
}
private Event readRealEvent() {
Event event = new Event();
event.type = pullNextEvent();
if (event.type == TEXT) {
event.value = pullText();
} else if (event.type == START_NODE) {
event.value = pullElementName();
}
return event;
}
public void mark() {
marked = true;
}
public void reset() {
while(lookahead.hasStuff()) {
lookback.push(lookahead.pop());
}
marked = false;
}
public String getValue() {
// we should collapse together any text which
// contains comments
// lets only use a string buffer when we get 2 strings
// to avoid copying strings
String last = null;
StringBuffer buffer = null;
mark();
Event event = readEvent();
while (true) {
if (event.type == TEXT) {
String text = event.value;
if (text != null && text.length() > 0) {
if (last == null) {
last = text;
} else {
if (buffer == null) {
buffer = new StringBuffer(last);
}
buffer.append(text);
}
}
} else if (event.type != COMMENT) {
break;
}
event = readEvent();
}
reset();
if (buffer != null) {
return buffer.toString();
} else {
return (last == null) ? "" : last;
}
}
public Iterator getAttributeNames() {
return new AttributeNameIterator(this);
}
public String getNodeName() {
return unescapeXmlName((String) elementStack.peek());
}
public HierarchicalStreamReader underlyingReader() {
return this;
}
}