Mercurial > hg > Members > kono > jpf-core
view src/main/gov/nasa/jpf/util/ArrayObjectQueue.java @ 2:b920e6b1be83
second part of the jpf-statechart motivated event interface overhaul, providing dynamic (context specific) expansion of EventTrees from within EventChoiceGenerators. This adds a EventContext mechanism that can replace events on-the-fly during advance() (e.g. expand wildcard patterns)
this also included the refined 'vm.extend.transitions' property, which is now a list of TypeSpecs (glob notation plus bounds) for CG types that should be subject to transition extension. We also support CheckExtendTransition attrs for CGs, which can be used to dynamically mark CGs. Note that each matching CG is still tested for non-rescheduling single choices
small Type/FeatureSpec extension to make it applicable to java.lang.Class instances. There is no reason why we can't make use of this for native types
author | Peter Mehlitz <Peter.C.Mehlitz@nasa.gov> |
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date | Sat, 24 Jan 2015 18:19:08 -0800 |
parents | 61d41facf527 |
children |
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/* * Copyright (C) 2014, United States Government, as represented by the * Administrator of the National Aeronautics and Space Administration. * All rights reserved. * * The Java Pathfinder core (jpf-core) platform is licensed under the * Apache License, Version 2.0 (the "License"); you may not use this file except * in compliance with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0. * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package gov.nasa.jpf.util; import java.util.Iterator; import java.util.NoSuchElementException; /** * dynamically growing, cyclic array buffer queue for object references */ public class ArrayObjectQueue<E> implements ObjectQueue<E> { static final int DEFAULT_CAPACITY = 256; int size = 0; int first; // next index we will remove int last; // last index we did add Object[] buffer = null; class FIFOIterator implements Iterator<E> { int next = first; int remaining = size; @Override public boolean hasNext() { return (remaining > 0); } @Override public E next() { if (remaining == 0){ throw new NoSuchElementException(); } else { E e = (E) buffer[next]; next = (next+1) % buffer.length; remaining--; return e; } } @Override public void remove() { // its a queue throw new UnsupportedOperationException(); } } // just for debugging purposes class StorageIterator implements Iterator<E> { int next = 0; @Override public boolean hasNext(){ return (next < buffer.length); } @Override public E next(){ if (next == buffer.length){ throw new NoSuchElementException(); } E e = (E) buffer[next]; next++; return e; } @Override public void remove() { // its a queue throw new UnsupportedOperationException(); } } public ArrayObjectQueue (){ buffer = new Object[DEFAULT_CAPACITY]; } public ArrayObjectQueue (int initialCapacity){ buffer = new Object[initialCapacity]; } protected void grow(){ Object[] newBuffer = new Object[buffer.length * 3 / 2]; if (first < last){ System.arraycopy(buffer, first, newBuffer, 0, last - first +1); } else if (first > last){ int nRight = buffer.length - first; System.arraycopy(buffer, first, newBuffer, 0, nRight); System.arraycopy(buffer, 0, newBuffer, nRight, last+1); } else { // just 1 element newBuffer[0] = buffer[first]; } first = 0; last = size-1; buffer = newBuffer; } @Override public boolean isEmpty() { return (size == 0); } public int getCurrentCapacity(){ return buffer.length; } @Override public int size() { return size; } @Override public boolean offer (E e){ return add(e); } @Override public boolean add (E e){ if (size == 0){ // first element first = last = 0; buffer[0] = e; size = 1; } else { int i = (last + 1) % buffer.length; if (i == first) { grow(); i = size; } last = i; buffer[i] = e; size++; } return true; // this is a dynamic queue, we never run out of space } @Override public E poll (){ if (size == 0){ return null; } else { int i = first; first = (first+1) % buffer.length; size--; E e = (E) buffer[i]; buffer[i] = null; // avoid memory leaks return e; } } @Override public E remove () throws NoSuchElementException { if (size == 0){ throw new NoSuchElementException(); } else { return poll(); } } @Override public E peek () { if (size == 0){ return null; } else { return (E)buffer[first]; } } @Override public Iterator<E> iterator() { return new FIFOIterator(); } public Iterator<E> storageIterator(){ return new StorageIterator(); } @Override public void clear(){ buffer = new Object[buffer.length]; // cheaper than iterating over the old one size = 0; first = last = -1; } /** * call Processor.process(e) on each queued object * * This method does not return before the queue is empty, which makes it * suitable for graph traversal. It also avoids iterator objects, allows * adding new objects while processing the queue, and enables to keep * processing state in the processor */ @Override public void process (Processor<E> processor){ while (size > 0){ E e = remove(); processor.process(e); } } }