l2j_mobius/trunk/java/commons/javaengine/JavaScriptEngineFactory.java

/*
 * Copyright (C) 2006 Sun Microsystems, Inc. All rights reserved. 
 * Use is subject to license terms.
 *
 * Redistribution and use in source and binary forms, with or without modification, are 
 * permitted provided that the following conditions are met: Redistributions of source code 
 * must retain the above copyright notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice, this list of 
 * conditions and the following disclaimer in the documentation and/or other materials 
 * provided with the distribution. Neither the name of the Sun Microsystems nor the names of 
 * is contributors may be used to endorse or promote products derived from this software 
 * without specific prior written permission. 

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER 
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package commons.javaengine;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;

/**
 * This is script engine factory for "Java" script engine.
 * @author A. Sundararajan
 */
public class JavaScriptEngineFactory implements ScriptEngineFactory
{
	@Override
	public String getEngineName()
	{
		return "java";
	}
	
	@Override
	public String getEngineVersion()
	{
		return "1.8";
	}
	
	@Override
	public List<String> getExtensions()
	{
		return extensions;
	}
	
	@Override
	public String getLanguageName()
	{
		return "java";
	}
	
	@Override
	public String getLanguageVersion()
	{
		return "1.8";
	}
	
	@Override
	public String getMethodCallSyntax(String obj, String m, String... args)
	{
		StringBuilder buf = new StringBuilder();
		buf.append(obj);
		buf.append('.');
		buf.append(m);
		buf.append('(');
		if (args.length != 0)
		{
			int i = 0;
			for (; i < (args.length - 1); i++)
			{
				buf.append(args[i] + ", ");
			}
			buf.append(args[i]);
		}
		buf.append(')');
		return buf.toString();
	}
	
	@Override
	public List<String> getMimeTypes()
	{
		return mimeTypes;
	}
	
	@Override
	public List<String> getNames()
	{
		return names;
	}
	
	@Override
	public String getOutputStatement(String toDisplay)
	{
		StringBuilder buf = new StringBuilder();
		buf.append("System.out.print(\"");
		int len = toDisplay.length();
		for (int i = 0; i < len; i++)
		{
			char ch = toDisplay.charAt(i);
			switch (ch)
			{
				case 34: // '"'
					buf.append("\\\"");
					break;
				case 92: // '\\'
					buf.append("\\\\");
					break;
				default:
					buf.append(ch);
					break;
			}
		}
		buf.append("\");");
		return buf.toString();
	}
	
	@Override
	public String getParameter(String key)
	{
		if (key.equals("javax.script.engine"))
		{
			return getEngineName();
		}
		if (key.equals("javax.script.engine_version"))
		{
			return getEngineVersion();
		}
		if (key.equals("javax.script.name"))
		{
			return getEngineName();
		}
		if (key.equals("javax.script.language"))
		{
			return getLanguageName();
		}
		if (key.equals("javax.script.language_version"))
		{
			return getLanguageVersion();
		}
		if (key.equals("THREADING"))
		{
			return "MULTITHREADED";
		}
		return null;
	}
	
	@Override
	public String getProgram(String... statements)
	{
		// we generate a Main class with main method
		// that contains all the given statements
		
		StringBuilder buf = new StringBuilder();
		buf.append("class ");
		buf.append(getClassName());
		buf.append(" {\n");
		buf.append("    public static void main(String[] args) {\n");
		if (statements.length != 0)
		{
			for (String statement : statements)
			{
				buf.append("        ");
				buf.append(statement);
				buf.append(";\n");
			}
		}
		buf.append("    }\n");
		buf.append("}\n");
		return buf.toString();
	}
	
	@Override
	public ScriptEngine getScriptEngine()
	{
		JavaScriptEngine engine = new JavaScriptEngine();
		engine.setFactory(this);
		return engine;
	}
	
	// used to generate a unique class name in getProgram
	private String getClassName()
	{
		return "com_sun_script_java_Main$" + getNextClassNumber();
	}
	
	private static synchronized long getNextClassNumber()
	{
		return nextClassNum++;
	}
	
	private static long nextClassNum = 0L;
	private static List<String> names;
	private static List<String> extensions;
	private static List<String> mimeTypes;
	
	static
	{
		names = new ArrayList<>(1);
		names.add("java");
		names = Collections.unmodifiableList(names);
		extensions = names;
		mimeTypes = new ArrayList<>(0);
		mimeTypes = Collections.unmodifiableList(mimeTypes);
	}
}