//
// Copyright (C) 2008 United States Government as represented by the
// Administrator of the National Aeronautics and Space Administration
// (NASA). All Rights Reserved.
//
// This software is distributed under the NASA Open Source Agreement
// (NOSA), version 1.3. The NOSA has been approved by the Open Source
// Initiative. See the file NOSA-1.3-JPF at the top of the distribution
// directory tree for the complete NOSA document.
//
// THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
// KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
// LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
// SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
// A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
// THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
// DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
//
package gov.nasa.jpf.util.script;
import java.io.StringReader;
import gov.nasa.jpf.util.script.ScriptElementContainer.SECIterator;
/**
* an interpreter that walks a ScriptElementContainer hierarchy, returning
* Events and Alternatives while expanding loops
*/
public class SequenceInterpreter implements Cloneable {
ScriptElementContainer.SECIterator top;
public SequenceInterpreter (ScriptElementContainer seq) {
top = seq.iterator();
}
void push (SECIterator it) {
it.prev = top;
top = it;
}
SECIterator pop () {
if (top != null) {
top = top.getPrev();
}
return top;
}
public ScriptElement getNext() {
if (top != null) {
ScriptElement e = top.next();
if (e != null) {
if ((e instanceof ScriptElementContainer) && !(e instanceof Alternative) ) {
push( ((ScriptElementContainer)e).iterator());
return getNext();
} else {
return e;
}
} else {
pop();
return (top != null) ? getNext() : null;
}
} else {
return null;
}
}
public Object clone() {
// has to deep copy all iterators
try {
SequenceInterpreter si = (SequenceInterpreter) super.clone();
if (top != null) {
si.top = (SECIterator)top.clone();
}
return si;
} catch (CloneNotSupportedException nonsense) {
return null; // we are a Cloneable, so we don't get here
}
}
public boolean isDone() {
return (top == null);
}
//---- test driver
public static void main (String[] args) {
//String s = "";
//String s = "a; b; c ";
//String s = "REPEAT 2 { e1, REPEAT 1 { r1, r2 }, e2 }";
//String s = "x, ANY {a1,a2}, y";
String s = "REPEAT 2 { start, ANY {a1,a2}, REPEAT 2 {r}, end }";
StringReader r = new StringReader(s);
try {
ESParser parser = new ESParser("test", r);
Script script = parser.parse();
SequenceInterpreter si = new SequenceInterpreter(script);
for (ScriptElement e = si.getNext(); e != null; e = si.getNext()) {
System.out.println(e);
}
} catch (Throwable t){
t.printStackTrace();
}
}
}