GmlEmitter.java

package nl.helixsoft.graph;

import java.io.BufferedOutputStream;
import java.io.OutputStream;
import java.io.PrintStream;

/**
 * Emitter that produces properly formatted GML to an OutputStream
 */
public class GmlEmitter implements Emitter
{
	private final PrintStream out;

	public GmlEmitter(OutputStream out)
	{
		this.out = new PrintStream (new BufferedOutputStream(out));
	}

	private String indent = "";

	public void startList(String key)
	{	
		out.print(indent);
		out.print(key);
		out.println(" [");
		indent += " ";
	}
	
	public void closeList()
	{
		indent = indent.substring(1);
		out.print(indent);
		out.println ("] ");
	}
	
	public void stringLiteral (String key, String value)
	{
		out.print(indent);
		out.print (key);
		out.print (" \"");
		//TODO: replace all ISO-8859-1 characters characters above ASCII code 127 this way
		out.print (value.replaceAll ("&", "&").replaceAll ("\"", """));
		out.println ("\"");			
	}

	public void intLiteral(String key, int value)
	{
		out.print(indent);
		out.print (key);
		out.println(" " + value);						
	}
	
	public void doubleLiteral(String key, double value)
	{
		out.print(indent);
		out.print (key);
		out.println(" " + value);						
	}

	public void numberLiteral(String key, Number value) 
	{
		out.print(indent);
		out.print (key);
		out.println(" " + value);								
	}

	public void close() 
	{
		out.close();
	}

}