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A collection of software for aggregatting and processing environmental data such as from NOAA GOES satellites.
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/*
* $Id$
*/
package ilex.xml;
import ilex.util.StringPair;
import ilex.util.TextUtil;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.BufferedWriter;
import java.io.IOException;
import java.nio.charset.Charset;
/**
This class implements methods for writing to an XML file.
It keeps track of indentation.
It manages the escape-sequences used for special characters.
*/
public class XmlOutputStream
{
// Set by constructor:
private OutputStream os;
private BufferedWriter osw;
private String top;
private int curIndent; // current level of indentation
/**
* Character(s) that are written for each level of indentation.
* By default this is two space characters.
* You can modify this string after creating the XmlOutputStream.
*/
public String indent;
/**
* Maximum width of a line.
* The outputter will attempt to break up strings that would cause a line
* to go over this limit.
*/
public int width;
/**
* Character(s) that are written for a newline.
* By default these are read from the system property "line.separator".
* You can modify this string after creating the XmlOutputStream.
*/
public String newline = System.getProperty("line.separator","\n");
/**
* URI of the DTD file (if any) that is associated with the XML file
* to be written.
* By default this is null (meaning standalone).
* You can modify this string after creating the XmlOutputStream.
*/
public String xmlDtdUri;
/**
* Scop of the DTD URI. Default="SYSTEM"
*/
public String xmlDtdScope;
/**
* XML Version of the file being written.
* By default this is 1.0.
* You can modify this string after creating the XmlOutputStream.
*/
public static String xmlVersion;
/**
* Creates an XmlOutputStream to write to the passed output stream.
* @param os the output stream
* @param top the name of the top element
*/
public XmlOutputStream( OutputStream os, String top )
{
this.os = os;
// XML requires UTF-8 encoding. This is NOT the default on windoze.
Charset utf8 = Charset.forName("UTF-8");
this.osw = new BufferedWriter(new OutputStreamWriter(os, utf8));
this.top= top;
curIndent = 0;
indent = " ";
width = 80;
newline = System.getProperty("line.separator", "\n");
xmlVersion = "1.0";
xmlDtdUri = null;
xmlDtdScope = "SYSTEM";
}
/**
* Writes the XML file header including version, URI, and top element name.
* @throws IOException on IO error
*/
public void writeXmlHeader( ) throws IOException
{
String h = "";
osw.write(h);
osw.write(newline);
if (xmlDtdUri != null)
{
h = "";
osw.write(h);
osw.write(newline);
}
osw.flush();
}
/**
* Starts an element with no attributes
* @param tag the element tag
* @throws IOException on IO error
*/
public void startElement( String tag ) throws IOException
{
startElement(tag, null);
}
/**
* Starts an element with a single attribute
* @param tag the element tag
* @param attName attribute name
* @param attValue attribute value
* @throws IOException on IO error
*/
public void startElement( String tag, String attName, String attValue ) throws IOException
{
StringPair sp[] = new StringPair[1];
sp[0] = new StringPair(attName, attValue);
startElement(tag, sp);
}
/**
* Starts an element with 2 attributes
* @param tag the element tag
* @throws IOException on IO error
* @param att1Name attribute name
* @param att1Value attribute value
* @param att2Name attribute name
* @param att2Value attribute value
*/
public void startElement( String tag, String att1Name, String att1Value, String att2Name, String att2Value ) throws IOException
{
StringPair sp[] = new StringPair[2];
sp[0] = new StringPair(att1Name, att1Value);
sp[1] = new StringPair(att2Name, att2Value);
startElement(tag, sp);
}
/**
* Starts an element with N attributes
* @param tag the element tag
* @param atts array of StringPair objects containing attribute name/values.
* @throws IOException on IO error
*/
public void startElement( String tag, StringPair[] atts ) throws IOException
{
String startTag = buildStartTag(tag, atts, false);
outputIndent();
osw.write(startTag);
osw.write(newline);
osw.flush();
curIndent++;
}
/**
* Ends an element.
* @param tag the element tag
* @throws IOException on IO error
*/
public void endElement( String tag ) throws IOException
{
if (curIndent > 0)
--curIndent;
outputIndent();
String t = "";
osw.write(t);
osw.write(newline);
osw.flush();
}
/**
* Writes PCDATA within the current element.
* @param data the data
* @throws IOException on IO error
*/
public void writePCDATA( String data ) throws IOException
{
if (data == null)
return;
data = escapeERs(data);
int pos = currentIndentPosition();
int w = pos < width ? width-pos : 40;
String[] lines = ilex.util.TextUtil.splitLine(data, w);
for(int i = 0; i < lines.length; i++)
{
outputIndent();
osw.write(lines[i]);
osw.write(newline);
}
osw.flush();
}
/**
* Writes a literal string with no substitutions.
* @param data the literal string
* @throws IOException on IO error
*/
public void writeLiteral(String data) throws IOException
{
osw.write(data);
osw.flush();
}
/**
* Writes an element with no attributes.
* If 'data' is null, an empty element is written with an elided end-tag.
* @param tag the element tag
* @param data the String content
* @throws IOException on IO error
*/
public void writeElement( String tag, String data ) throws IOException
{
writeElement(tag, (StringPair[])null, data);
}
/**
* Writes an element with one attribute.
* If 'data' is null, an empty element is written with an elided end-tag.
* @param tag the element tag
* @param data the String content
* @param attName attribute name
* @param attValue attribute value
* @throws IOException on IO error
*/
public void writeElement( String tag, String attName, String attValue, String data ) throws IOException
{
StringPair sp[] = new StringPair[1];
sp[0] = new StringPair(attName, attValue);
writeElement(tag, sp, data);
}
/**
* Writes an element with two attributes.
* If 'data' is null, an empty element is written with an elided end-tag.
* @param tag the element tag
* @param data the String content
* @param att1Name attribute name
* @param att1Value attribute value
* @param att2Name attribute name
* @param att2Value attribute value
* @throws IOException on IO error
*/
public void writeElement( String tag, String att1Name, String att1Value, String att2Name, String att2Value, String data ) throws IOException
{
StringPair sp[] = new StringPair[2];
sp[0] = new StringPair(att1Name, att1Value);
sp[1] = new StringPair(att2Name, att2Value);
writeElement(tag, sp, data);
}
/**
* Writes an element with an arbitrary number of attributes.
* If 'data' is null, an empty element is written with an elided end-tag.
* @param tag the element tag
* @param data the String content
* @param atts array of StringPair objects containing name/value pairs.
* @throws IOException on IO error
*/
public void writeElement( String tag, StringPair[] atts, String data ) throws IOException
{
String startTag = buildStartTag(tag, atts, data == null);
boolean oneLine = (data == null)
|| (currentIndentPosition() + startTag.length() +
data.length() + 3 + tag.length() <= width);
if (!oneLine)
{
startElement(tag, atts);
writePCDATA(data);
endElement(tag);
}
else // Everything will fit on one line.
{
outputIndent();
osw.write(startTag);
if (data != null)
{
osw.write(escapeERs(data));
String s = "";
osw.write(s);
}
osw.write(newline);
}
}
/**
* @throws IOException
*/
private void outputIndent( ) throws IOException
{
for(int i = 0; i < curIndent; i++)
osw.write(indent);
}
/**
* @return
*/
private int currentIndentPosition( )
{
int inc = 0;
for(int i = 0; i < indent.length(); i++)
if (indent.charAt(i) == '\t')
inc += 4;
else
inc++;
return inc * curIndent;
}
/**
* Internal utility: builds the start tag (without indentation)
* If 'empty' is true, the tag will be terminated with "/>".
* @param tag
* @param atts
* @param empty
* @return
*/
private String buildStartTag( String tag, StringPair[] atts, boolean empty )
{
StringBuffer sb = new StringBuffer("<"+tag);
if (atts != null)
for(int i = 0; i')
{
sb.setCharAt(i, '&');
sb.insert(++i, "gt;");
i+=2;
}
else if (c == '"')
{
sb.setCharAt(i, '&');
sb.insert(++i, "quot;");
i+=4;
}
else if (c == '\'')
{
sb.setCharAt(i, '&');
sb.insert(++i, "apos;");
i+=4;
}
else if (c == '\\')
{
sb.setCharAt(i, '&');
sb.insert(++i, "#92;");
i+=3;
}
else if (c > 126
|| (c < '\u0020' && c != '\n' && c != '\r' && c != '\t'))
{
sb.setCharAt(i, '&');
String ins = "#" + (int)c + ";";
sb.insert(++i, ins);
i += ins.length();
}
}
return sb.toString();
}
/*
Utility method to escape any linefeed '\n' and carriage-return '\r'
characters with the hexadecimal equivalent. This way, they will survive
being written to, and read from, and XML file.
*/
// public String escapeNLs(String s)
// {
// StringBuffer sb = new StringBuffer();
// int len=s.length();
// for(int i=0; i