tuwien.auto.calimero.xml.def.DefaultXMLReader Maven / Gradle / Ivy
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/*
Calimero 2 - A library for KNX network access
Copyright (c) 2006, 2015 B. Malinowsky
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under terms
of your choice, provided that you also meet, for each linked independent
module, the terms and conditions of the license of that module. An
independent module is a module which is not derived from or based on
this library. If you modify this library, you may extend this exception
to your version of the library, but you are not obligated to do so. If
you do not wish to do so, delete this exception statement from your
version.
*/
package tuwien.auto.calimero.xml.def;
import java.io.IOException;
import java.io.Reader;
import java.util.Stack;
import tuwien.auto.calimero.xml.Attribute;
import tuwien.auto.calimero.xml.Element;
import tuwien.auto.calimero.xml.KNXMLException;
import tuwien.auto.calimero.xml.XMLReader;
/**
* Default XML reader implementation of the XMLReader interface.
*
* Does not add any feature not already documented in the implemented interface.
* This reader is not thread safe.
*
* @author B. Malinowsky
*/
public class DefaultXMLReader implements XMLReader
{
private Reader r;
private boolean closeReader;
private Element elem;
private final Stack openElems = new Stack();
private int pos;
private int line;
/**
* Creates a new XML reader.
*
*/
public DefaultXMLReader()
{}
/**
* Creates a new XML reader with input r.
*
* The {@link Reader} should already be buffered or wrapped with a buffered reader, if
* necessary (e.g. when reading from a file).
*
* @param r a {@link Reader} for input
* @param close true to close r if XML reader is closed,
* false otherwise
* @see XMLReader#setInput(Reader, boolean)
*/
public DefaultXMLReader(final Reader r, final boolean close)
{
reset();
setInput(r, close);
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.xml.XMLReader#setInput(java.io.Reader, boolean)
*/
public void setInput(final Reader input, final boolean close)
{
if (r != null)
reset();
r = input;
closeReader = close;
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.xml.XMLReader#read()
*/
public int read() throws KNXMLException
{
while (canRead()) {
// init line counter on first read
if (line == 0)
line = 1;
read('<');
String str = read('>');
// if no comment and no closing tag
if (str.length() == 0 || skipComment(str) || skipInstruction(str))
continue;
final StringBuffer buf = new StringBuffer();
if (readCDATASection(str, buf)) {
elem = new DefaultElement((String) openElems.peek());
elem.setCharacterData(buf.toString());
pos = CHAR_DATA;
return pos;
}
str = str.trim();
// extract element name
String name = splitOnSpace(str);
if (name.charAt(name.length() - 1) == '/')
name = name.substring(0, name.length() - 1);
if (name.charAt(0) == '/') {
if (!name.substring(1).equals(openElems.peek()))
throw new KNXMLException("element end tag does not match start tag",
name.substring(1), line);
elem = new DefaultElement((String) openElems.pop());
pos = END_TAG;
return pos;
}
elem = new DefaultElement(name);
extractAttributes(str.substring(name.length()));
if (!elem.isEmptyElementTag())
openElems.push(name);
pos = START_TAG;
return pos;
}
if (!openElems.empty())
throw new KNXMLException("end of XML input with elements left open");
pos = END_DOC;
return pos;
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.xml.XMLReader#complete(tuwien.auto.calimero.xml.Element)
*/
public void complete(final Element e) throws KNXMLException
{
if (e.isEmptyElementTag())
return;
final int index = openElems.lastIndexOf(e.getName());
if (index == -1)
throw new KNXMLException("no matching element open tag: " + e.getName(), this);
String end = null;
final StringBuffer content = new StringBuffer(50);
while (canRead()) {
// read text content
final String s = read('<');
final boolean current = openElems.peek().equals(e.getName());
// if character data is for current element, append it
if (current && s.length() > 0)
content.append(References.replace(s, false));
// read a possible end tag
end = read('>');
if (skipComment(end))
;
else if (current && readCDATASection(end, content))
;
else if (end.length() > 0 && end.charAt(0) == '/') {
// actually, no white space is allowed between '/' and tag name
// but there might be some between end of name and '>'
final String tag = end.substring(1).trim();
// got end tag?
if (!tag.equals(openElems.peek()))
throw new KNXMLException("element end tag does not match start tag", tag, line);
openElems.pop();
if (tag.equals(e.getName())) {
e.setCharacterData(content.toString());
pos = END_TAG;
return;
}
}
else if (end.length() > 0)
// don't push empty element tags
if (end.charAt(end.length() - 1) != '/') {
final String tag = splitOnSpace(end);
if (tag.length() > 0)
openElems.push(tag);
}
}
throw new KNXMLException("end of XML input with elements left open", end, line);
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.xml.XMLReader#getCurrent()
*/
public final Element getCurrent()
{
return elem;
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.xml.XMLReader#getPosition()
*/
public final int getPosition()
{
return pos;
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.xml.XMLReader#getLineNumber()
*/
public final int getLineNumber()
{
return line;
}
/* (non-Javadoc)
* @see tuwien.auto.calimero.xml.XMLReader#close()
*/
public void close() throws KNXMLException
{
if (closeReader)
try {
r.close();
}
catch (final IOException e) {
throw new KNXMLException(e.getMessage());
}
}
private boolean canRead()
{
try {
return r.ready();
}
catch (final IOException e) {
return false;
}
}
private String read(final char delimiter) throws KNXMLException
{
final StringBuffer buf = new StringBuffer(50);
try {
boolean cr = false;
for (int c = 0; (c = r.read()) != -1 && c != delimiter;) {
if (c == '\n')
++line;
else if (cr) {
++line;
buf.append('\n');
}
cr = c == '\r';
if (!cr)
buf.append((char) c);
}
}
catch (final IOException e) {
throw new KNXMLException(e.getMessage(), buf.toString(), line);
}
return buf.toString();
}
// adds all available attributes to current element
private void extractAttributes(final String attributes)
{
String s = attributes.trim();
if (s.length() > 0 && s.charAt(s.length() - 1) == '/')
elem.setEmptyElementTag(true);
while (s.length() != 0) {
final int equal = s.indexOf('=');
if (equal == -1 || equal == s.length() - 1)
break;
// cut off attribute name
final String att = s.substring(0, equal).trim();
s = s.substring(equal + 1).trim();
if (s.length() == 0)
break;
final boolean quote = s.charAt(0) == '\'' || s.charAt(0) == '\"';
if (att.length() > 0 && quote) {
String value = s.substring(1);
final int end = value.indexOf(s.charAt(0));
if (end >= 0)
value = value.substring(0, end);
elem.addAttribute(new Attribute(att, References.replace(value, false)));
}
final int i = s.indexOf(quote ? s.charAt(0) : ' ', 1);
s = i == -1 ? "" : s.substring(i + 1);
}
}
private boolean readCDATASection(final String s, final StringBuffer buf) throws KNXMLException
{
if (!s.startsWith("![CDATA["))
return false;
buf.append(s.substring(8));
String cdata = s;
while (!cdata.endsWith("]]")) {
buf.append('>');
cdata = read('>');
buf.append(cdata);
}
// trim CDEnd ('>' is not included)
buf.delete(buf.length() - 2, buf.length());
return true;
}
// checks if '<' marks begin of a comment, and if so skips over it
private boolean skipComment(final String s) throws KNXMLException
{
if (s.startsWith("!--")) {
String comment = s;
while (canRead() && !comment.endsWith("--"))
comment = read('>');
return true;
}
return false;
}
private boolean skipInstruction(final String tag)
{
// is this a processing instruction
if (tag.charAt(0) == '?' && tag.charAt(tag.length() - 1) == '?')
return true;
return false;
}
private String splitOnSpace(final String s)
{
for (int i = 0; i < s.length(); ++i)
if (Character.isSpaceChar(s.charAt(i)))
return s.substring(0, i);
return s;
}
private void reset()
{
elem = null;
openElems.clear();
pos = START_DOC;
line = 0;
}
}