public  void callFunction(String funName,
    List params,
    Environment environment,
    InvokeContext ctx) throws Exception 
{
    checkForModifiedScripts(environment);
    sisc.Interpreter interp = getInterpreter();
    Map dynVars = interp.dynenv.parameters;
    try {
      int size = params.size();
      Value[] args = new Value[size];
      for (int i = 0; i <  size; i++) {
        args[i]
          = new ImmutableString(((Interpreter.Argument)params.get(i)).value);
      }
      Symbol funSym = Symbol.get(funName);
      Procedure function = (Procedure)interp.ctx.toplevel_env.lookup(funSym);
      interp.eval(function, args);
    }
    finally {
      releaseInterpreter(interp);
    }
}

 public  void configure(Configuration confs) throws ConfigurationException 
{
    String heapFileName = confs.getAttribute("heap", null);
    if (heapFileName == null)
      throw new ConfigurationException("Heap Scheme file not specified");
    siscContext = new AppContext();
    interPool = new ArrayList();
    sisc.Interpreter interp = getInterpreter();
    try {
      org.apache.cocoon.environment.Context context =
        (org.apache.cocoon.environment.Context)cocoonContext.get(Constants.CONTEXT_ENVIRONMENT_CONTEXT);
      System.out.println("Loading heap "
                         + context.getResource(heapFileName));
      InputStream is = context.getResource(heapFileName).openStream();
      BufferedInputStream bis = new BufferedInputStream(is);
      GZIPInputStream gzis = new GZIPInputStream(bis);
      DataInputStream dis
        = new DataInputStream(new BufferedInputStream(gzis));
      siscContext.loadEnv(interp, dis);
    }
    catch (Exception ex) {
      System.err.println("Error loading heap:" + ex);
      ex.printStackTrace();
      throw new ConfigurationException("Cannot load heap file: " + ex);
    }
    siscContext.setEvaluator("eval");
}

 public  void contextualize(Context context) throws ContextException 
{
    this.cocoonContext = context;
}

 public Interpreter getInterpreter() 
{
    synchronized(interPool) {
      int size = interPool.size();
      if (size != 0)
        return (sisc.Interpreter)interPool.remove(size - 1);
    }
    // Create a new interpreter and return it
    DynamicEnv environment = new DynamicEnv(System.in, System.out);
    environment.parameters.put("environment", null);
    sisc.Interpreter interp = new sisc.Interpreter(siscContext, environment);
    return interp;
}

Obtain a Scheme Interpreter from the internal pool of interpreters.

 public  void handleContinuation(String continuationId,
    Environment environment,
    InvokeContext ctx) throws Exception 
{

}

 public Source readScript(Environment environment,
    String sourceName) throws Exception 
{
    Source source = null;
    System.out.println("Reading file " + sourceName);
    sisc.Interpreter interp = getInterpreter();
    try {
      source = environment.resolve(sourceName);
      InputStream inputStream = source.getInputStream();
      Reader reader = new BufferedReader(new InputStreamReader(inputStream));
      StringBuffer buffer = new StringBuffer();
      char[] cbuf = new char[1024];
      int len;
      while ((len = reader.read(cbuf)) != -1)
        buffer.append(cbuf, 0, len);
      interp.eval(buffer.toString());
    }
    finally {
      releaseInterpreter(interp);
    }
    return source;
}

 public  void releaseInterpreter(Interpreter interp) 
{
    synchronized(interPool) {
      interPool.add(interp);
    }
}

Put back into the pool an Interpreter instance.