/*
* #!
* Ontopia Engine
* #-
* Copyright (C) 2001 - 2013 The Ontopia Project
* #-
* 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 net.ontopia.xml;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import net.ontopia.utils.OntopiaRuntimeException;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
/**
* INTERNAL: SAX document handler that writes pretty-printed XML to a
* Writer.
*/
public class PrettyPrinter implements ContentHandler {
private static final String NL = System.getProperty("line.separator");
protected Writer writer;
protected String encoding;
protected boolean[] subelements;
protected char[] startline; // contains "\n ...", used for indents
protected int offset; // width of newline (1-2 chars)
protected int level; // current element depth
protected int encodeCharsFrom = -1;
protected boolean dropControlChars = true; // drop control chars by default
/**
* Creates a PrettyPrinter that writes to the given OutputStream.
* The encoding used is always utf-8.
*/
public PrettyPrinter(OutputStream stream) throws UnsupportedEncodingException {
this(stream, "utf-8");
}
/**
* Creates a PrettyPrinter that writes to the given OutputStream
* in the requested character encoding.
*/
public PrettyPrinter(OutputStream stream, String encoding) throws UnsupportedEncodingException {
this(new OutputStreamWriter(stream, encoding), encoding);
}
/**
* Creates a PrettyPrinter that writes to the given Writer.
* @param encoding The encoding to report in the XML declaration. If null,
* no XML declaration will be output.
*/
public PrettyPrinter(Writer writer, String encoding) {
this.writer = writer;
this.encoding = encoding;
makeSubelements(20);
makeStartLineBuffer(100);
}
// --------------------------------------------------------------------------
// Document events
// --------------------------------------------------------------------------
public void startDocument() {
if (encoding != null) {
write(writer, "<?xml version=\"1.0\" encoding=\"");
write(writer, encoding);
write(writer, "\" standalone=\"yes\"?>" + NL);
}
level = 0;
}
public void startElement(String uri, String localName, String qName, Attributes atts) {
if (level > 0)
indent();
// Write start tag
write(writer, '<');
write(writer, qName);
for (int i = 0; i < atts.getLength(); i++) {
write(writer, ' ');
write(writer, atts.getQName(i));
write(writer, "=\"");
escapeAttrValue(atts.getValue(i), writer);
write(writer, "\"");
}
write(writer, '>');
level++;
// check arrays are still of right size
if (offset + level*2 > startline.length)
makeStartLineBuffer((offset + level*2) * 2);
if (level >= subelements.length)
makeSubelements(level * 2);
// Set sub element flag on parent element to true
if (level > 0)
subelements[level - 1] = true;
// Set sub element flag on this element to false
subelements[level] = false;
}
public void endElement(String uri, String localName, String qName) {
if (subelements[level--])
indent();
write(writer, "</");
write(writer, qName);
write(writer, '>');
}
public void characters(char ch[], int start, int length) {
// Encode characters as decimal character entities
for (int i = start; i < start + length; i++) {
switch(ch[i]) {
case '&':
write(writer, "&");
break;
case '<':
write(writer, "<");
break;
case '>':
write(writer, ">");
break;
default:
if (ch[i] > 31 || ch[i] == '\n' || ch[i] == '\t' || ch[i] == '\r') {
if (encodeCharsFrom > 0 && ch[i] >= encodeCharsFrom) {
write(writer, "&#");
write(writer, Integer.toString((int)ch[i]));
write(writer, ';');
} else {
write(writer, ch[i]);
}
} else {
if (!dropControlChars) {
// escape control characters
write(writer, "&#");
write(writer, Integer.toString((int)ch[i]));
write(writer, ';');
}
}
}
}
}
public void ignorableWhitespace(char ch[], int start, int length) {
}
public void processingInstruction(String target, String data) {
// Write processing instruction
write(writer, "<?");
write(writer, target);
write(writer, ' ');
write(writer, data);
write(writer, "?>");
}
public void endDocument() {
write(writer, NL);
flush(writer);
}
public void setDocumentLocator(Locator locator) {
}
/**
* INTERNAL: Encodes element content as decimal character entitites
* for characters from the given character number.
*/
public void setEncodeCharactersFrom(int charnumber) {
this.encodeCharsFrom = charnumber;
}
/**
* INTERNAL: If this property is true control characters are being
* dropped from the resulting document.
*/
public void setDropControlCharacters(boolean dropControlChars) {
this.dropControlChars = dropControlChars;
}
/**
* INTERNAL: Add given text unmodified and unescaped to the output.
* <b>BEWARE:</b> This makes it possible (even easy) to produce
* output that is not well-formed.
*/
public void addUnescaped(String content) {
write(writer, content);
}
// --------------------------------------------------------------------------
// Helper methods
// --------------------------------------------------------------------------
protected void write(Writer writer, String s) {
try {
writer.write(s);
} catch (IOException e) {
throw new OntopiaRuntimeException(e);
}
}
protected void write(Writer writer, char c) {
try {
writer.write(c);
} catch (IOException e) {
throw new OntopiaRuntimeException(e);
}
}
protected void write(Writer writer, char[] c, int off, int len) {
try {
writer.write(c, off, len);
} catch (IOException e) {
throw new OntopiaRuntimeException(e);
}
}
protected void flush(Writer writer) {
try {
writer.flush();
} catch (IOException e) {
throw new OntopiaRuntimeException(e);
}
}
protected void indent() {
write(writer, startline, 0, offset + level * 2);
}
protected void escapeAttrValue(String attrval, Writer writer) {
int len = attrval.length();
for (int i=0; i < len; i++) {
char c = attrval.charAt(i);
switch(c) {
case '&':
write(writer, "&");
break;
case '<':
write(writer, "<");
break;
case '"':
write(writer, """);
break;
default:
if (c > 31 || c == '\n' || c == '\t' || c == '\r') {
if (encodeCharsFrom > 0 && c >= encodeCharsFrom) {
write(writer, "&#");
write(writer, Integer.toString((int)c));
write(writer, ';');
} else {
write(writer, c);
}
} else {
if (!dropControlChars) {
// escape control characters
write(writer, "&#");
write(writer, Integer.toString((int)c));
write(writer, ';');
}
}
}
}
}
protected void makeStartLineBuffer(int size) {
startline = new char[size];
offset = NL.length();
int ix = 0;
for (; ix < offset; ix++)
startline[ix] = NL.charAt(ix);
for (; ix < size; ix++)
startline[ix] = ' ';
}
protected void makeSubelements(int size) {
boolean subs[] = new boolean[size];
if (subelements != null)
System.arraycopy(subelements, 0, subs, 0, subelements.length);
subelements = subs;
}
public void startPrefixMapping(String prefix, String uri) throws SAXException {
}
public void endPrefixMapping(String prefix) throws SAXException {
}
public void skippedEntity(String name) throws SAXException {
}
}