--- /dev/null
+package test.javassist.convert;
+
+import java.util.AbstractQueue;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
+
+/**
+ * A clone of java.util.concurrent.ArrayBlockingQueue as target for testing
+ */
+public class InstrumentationTarget<E> extends AbstractQueue<E>
+ implements BlockingQueue<E>, java.io.Serializable {
+ /**
+ * Serialization ID. This class relies on default serialization
+ * even for the items array, which is default-serialized, even if
+ * it is empty. Otherwise it could not be declared final, which is
+ * necessary here.
+ */
+ private static final long serialVersionUID = -817911632652898426L;
+
+ /**
+ * The queued items
+ */
+ final Object[] items;
+
+ /**
+ * items index for next take, poll, peek or remove
+ */
+ int takeIndex;
+
+ /**
+ * items index for next put, offer, or add
+ */
+ int putIndex;
+
+ /**
+ * Number of elements in the queue
+ */
+ int count;
+
+ /*
+ * Concurrency control uses the classic two-condition algorithm
+ * found in any textbook.
+ */
+
+ /**
+ * Main lock guarding all access
+ */
+ final ReentrantLock lock;
+ /**
+ * Condition for waiting takes
+ */
+ private final Condition notEmpty;
+ /**
+ * Condition for waiting puts
+ */
+ private final Condition notFull;
+
+ // Internal helper methods
+
+ /**
+ * Circularly increment i.
+ */
+ final int inc(int i) {
+ return (++i == items.length) ? 0 : i;
+ }
+
+ /**
+ * Circularly decrement i.
+ */
+ final int dec(int i) {
+ return ((i == 0) ? items.length : i) - 1;
+ }
+
+ @SuppressWarnings("unchecked")
+ static <E> E cast(Object item) {
+ return (E) item;
+ }
+
+ /**
+ * Returns item at index i.
+ */
+ final E itemAt(int i) {
+ return this.<E>cast(items[i]);
+ }
+
+ /**
+ * Throws NullPointerException if argument is null.
+ *
+ * @param v the element
+ */
+ private static void checkNotNull(Object v) {
+ if (v == null)
+ throw new NullPointerException();
+ }
+
+ /**
+ * Inserts element at current put position, advances, and signals.
+ * Call only when holding lock.
+ */
+ private void insert(E x) {
+ items[putIndex] = x;
+ putIndex = inc(putIndex);
+ ++count;
+ notEmpty.signal();
+ }
+
+ /**
+ * Extracts element at current take position, advances, and signals.
+ * Call only when holding lock.
+ */
+ private E extract() {
+ final Object[] items = this.items;
+ E x = this.<E>cast(items[takeIndex]);
+ items[takeIndex] = null;
+ takeIndex = inc(takeIndex);
+ --count;
+ notFull.signal();
+ return x;
+ }
+
+ /**
+ * Deletes item at position i.
+ * Utility for remove and iterator.remove.
+ * Call only when holding lock.
+ */
+ void removeAt(int i) {
+ final Object[] items = this.items;
+ // if removing front item, just advance
+ if (i == takeIndex) {
+ items[takeIndex] = null;
+ takeIndex = inc(takeIndex);
+ } else {
+ // slide over all others up through putIndex.
+ for (; ; ) {
+ int nexti = inc(i);
+ if (nexti != putIndex) {
+ items[i] = items[nexti];
+ i = nexti;
+ } else {
+ items[i] = null;
+ putIndex = i;
+ break;
+ }
+ }
+ }
+ --count;
+ notFull.signal();
+ }
+
+ /**
+ * Creates an {@code Target} with the given (fixed)
+ * capacity and default access policy.
+ *
+ * @param capacity the capacity of this queue
+ * @throws IllegalArgumentException if {@code capacity < 1}
+ */
+ public InstrumentationTarget(int capacity) {
+ this(capacity, false);
+ }
+
+ /**
+ * Creates an {@code Target} with the given (fixed)
+ * capacity and the specified access policy.
+ *
+ * @param capacity the capacity of this queue
+ * @param fair if {@code true} then queue accesses for threads blocked
+ * on insertion or removal, are processed in FIFO order;
+ * if {@code false} the access order is unspecified.
+ * @throws IllegalArgumentException if {@code capacity < 1}
+ */
+ public InstrumentationTarget(int capacity, boolean fair) {
+ if (capacity <= 0)
+ throw new IllegalArgumentException();
+ this.items = new Object[capacity];
+ lock = new ReentrantLock(fair);
+ notEmpty = lock.newCondition();
+ notFull = lock.newCondition();
+ }
+
+ /**
+ * Creates an {@code Target} with the given (fixed)
+ * capacity, the specified access policy and initially containing the
+ * elements of the given collection,
+ * added in traversal order of the collection's iterator.
+ *
+ * @param capacity the capacity of this queue
+ * @param fair if {@code true} then queue accesses for threads blocked
+ * on insertion or removal, are processed in FIFO order;
+ * if {@code false} the access order is unspecified.
+ * @param c the collection of elements to initially contain
+ * @throws IllegalArgumentException if {@code capacity} is less than
+ * {@code c.size()}, or less than 1.
+ * @throws NullPointerException if the specified collection or any
+ * of its elements are null
+ */
+ public InstrumentationTarget(int capacity, boolean fair,
+ Collection<? extends E> c) {
+ this(capacity, fair);
+
+ final ReentrantLock lock = this.lock;
+ lock.lock(); // Lock only for visibility, not mutual exclusion
+ try {
+ int i = 0;
+ try {
+ for (E e : c) {
+ checkNotNull(e);
+ items[i++] = e;
+ }
+ } catch (ArrayIndexOutOfBoundsException ex) {
+ throw new IllegalArgumentException();
+ }
+ count = i;
+ putIndex = (i == capacity) ? 0 : i;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Inserts the specified element at the tail of this queue if it is
+ * possible to do so immediately without exceeding the queue's capacity,
+ * returning {@code true} upon success and throwing an
+ * {@code IllegalStateException} if this queue is full.
+ *
+ * @param e the element to add
+ * @return {@code true} (as specified by {@link Collection#add})
+ * @throws IllegalStateException if this queue is full
+ * @throws NullPointerException if the specified element is null
+ */
+ public boolean add(E e) {
+ return super.add(e);
+ }
+
+ /**
+ * Inserts the specified element at the tail of this queue if it is
+ * possible to do so immediately without exceeding the queue's capacity,
+ * returning {@code true} upon success and {@code false} if this queue
+ * is full. This method is generally preferable to method {@link #add},
+ * which can fail to insert an element only by throwing an exception.
+ *
+ * @throws NullPointerException if the specified element is null
+ */
+ public boolean offer(E e) {
+ checkNotNull(e);
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ if (count == items.length)
+ return false;
+ else {
+ insert(e);
+ return true;
+ }
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Inserts the specified element at the tail of this queue, waiting
+ * for space to become available if the queue is full.
+ *
+ * @throws InterruptedException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ */
+ public void put(E e) throws InterruptedException {
+ checkNotNull(e);
+ final ReentrantLock lock = this.lock;
+ lock.lockInterruptibly();
+ try {
+ while (count == items.length)
+ notFull.await();
+ insert(e);
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Inserts the specified element at the tail of this queue, waiting
+ * up to the specified wait time for space to become available if
+ * the queue is full.
+ *
+ * @throws InterruptedException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ */
+ public boolean offer(E e, long timeout, TimeUnit unit)
+ throws InterruptedException {
+
+ checkNotNull(e);
+ long nanos = unit.toNanos(timeout);
+ final ReentrantLock lock = this.lock;
+ lock.lockInterruptibly();
+ try {
+ while (count == items.length) {
+ if (nanos <= 0)
+ return false;
+ nanos = notFull.awaitNanos(nanos);
+ }
+ insert(e);
+ return true;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ public E poll() {
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ return (count == 0) ? null : extract();
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ public E take() throws InterruptedException {
+ final ReentrantLock lock = this.lock;
+ lock.lockInterruptibly();
+ try {
+ while (count == 0)
+ notEmpty.await();
+ return extract();
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ public E poll(long timeout, TimeUnit unit) throws InterruptedException {
+ long nanos = unit.toNanos(timeout);
+ final ReentrantLock lock = this.lock;
+ lock.lockInterruptibly();
+ try {
+ while (count == 0) {
+ if (nanos <= 0)
+ return null;
+ nanos = notEmpty.awaitNanos(nanos);
+ }
+ return extract();
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ public E peek() {
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ return (count == 0) ? null : itemAt(takeIndex);
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ // this doc comment is overridden to remove the reference to collections
+ // greater in size than Integer.MAX_VALUE
+
+ /**
+ * Returns the number of elements in this queue.
+ *
+ * @return the number of elements in this queue
+ */
+ public int size() {
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ return count;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ // this doc comment is a modified copy of the inherited doc comment,
+ // without the reference to unlimited queues.
+
+ /**
+ * Returns the number of additional elements that this queue can ideally
+ * (in the absence of memory or resource constraints) accept without
+ * blocking. This is always equal to the initial capacity of this queue
+ * less the current {@code size} of this queue.
+ *
+ * <p>Note that you <em>cannot</em> always tell if an attempt to insert
+ * an element will succeed by inspecting {@code remainingCapacity}
+ * because it may be the case that another thread is about to
+ * insert or remove an element.
+ */
+ public int remainingCapacity() {
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ return items.length - count;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Removes a single instance of the specified element from this queue,
+ * if it is present. More formally, removes an element {@code e} such
+ * that {@code o.equals(e)}, if this queue contains one or more such
+ * elements.
+ * Returns {@code true} if this queue contained the specified element
+ * (or equivalently, if this queue changed as a result of the call).
+ *
+ * <p>Removal of interior elements in circular array based queues
+ * is an intrinsically slow and disruptive operation, so should
+ * be undertaken only in exceptional circumstances, ideally
+ * only when the queue is known not to be accessible by other
+ * threads.
+ *
+ * @param o element to be removed from this queue, if present
+ * @return {@code true} if this queue changed as a result of the call
+ */
+ public boolean remove(Object o) {
+ if (o == null) return false;
+ final Object[] items = this.items;
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ for (int i = takeIndex, k = count; k > 0; i = inc(i), k--) {
+ if (o.equals(items[i])) {
+ removeAt(i);
+ return true;
+ }
+ }
+ return false;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Returns {@code true} if this queue contains the specified element.
+ * More formally, returns {@code true} if and only if this queue contains
+ * at least one element {@code e} such that {@code o.equals(e)}.
+ *
+ * @param o object to be checked for containment in this queue
+ * @return {@code true} if this queue contains the specified element
+ */
+ public boolean contains(Object o) {
+ if (o == null) return false;
+ final Object[] items = this.items;
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ for (int i = takeIndex, k = count; k > 0; i = inc(i), k--)
+ if (o.equals(items[i]))
+ return true;
+ return false;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Returns an array containing all of the elements in this queue, in
+ * proper sequence.
+ *
+ * <p>The returned array will be "safe" in that no references to it are
+ * maintained by this queue. (In other words, this method must allocate
+ * a new array). The caller is thus free to modify the returned array.
+ *
+ * <p>This method acts as bridge between array-based and collection-based
+ * APIs.
+ *
+ * @return an array containing all of the elements in this queue
+ */
+ public Object[] toArray() {
+ final Object[] items = this.items;
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ final int count = this.count;
+ Object[] a = new Object[count];
+ for (int i = takeIndex, k = 0; k < count; i = inc(i), k++)
+ a[k] = items[i];
+ return a;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Returns an array containing all of the elements in this queue, in
+ * proper sequence; the runtime type of the returned array is that of
+ * the specified array. If the queue fits in the specified array, it
+ * is returned therein. Otherwise, a new array is allocated with the
+ * runtime type of the specified array and the size of this queue.
+ *
+ * <p>If this queue fits in the specified array with room to spare
+ * (i.e., the array has more elements than this queue), the element in
+ * the array immediately following the end of the queue is set to
+ * {@code null}.
+ *
+ * <p>Like the {@link #toArray()} method, this method acts as bridge between
+ * array-based and collection-based APIs. Further, this method allows
+ * precise control over the runtime type of the output array, and may,
+ * under certain circumstances, be used to save allocation costs.
+ *
+ * <p>Suppose {@code x} is a queue known to contain only strings.
+ * The following code can be used to dump the queue into a newly
+ * allocated array of {@code String}:
+ *
+ * <pre>
+ * String[] y = x.toArray(new String[0]);</pre>
+ * <p>
+ * Note that {@code toArray(new Object[0])} is identical in function to
+ * {@code toArray()}.
+ *
+ * @param a the array into which the elements of the queue are to
+ * be stored, if it is big enough; otherwise, a new array of the
+ * same runtime type is allocated for this purpose
+ * @return an array containing all of the elements in this queue
+ * @throws ArrayStoreException if the runtime type of the specified array
+ * is not a supertype of the runtime type of every element in
+ * this queue
+ * @throws NullPointerException if the specified array is null
+ */
+ @SuppressWarnings("unchecked")
+ public <T> T[] toArray(T[] a) {
+ final Object[] items = this.items;
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ final int count = this.count;
+ final int len = a.length;
+ if (len < count)
+ a = (T[]) java.lang.reflect.Array.newInstance(
+ a.getClass().getComponentType(), count);
+ for (int i = takeIndex, k = 0; k < count; i = inc(i), k++)
+ a[k] = (T) items[i];
+ if (len > count)
+ a[count] = null;
+ return a;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ public String toString() {
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ int k = count;
+ if (k == 0)
+ return "[]";
+
+ StringBuilder sb = new StringBuilder();
+ sb.append('[');
+ for (int i = takeIndex; ; i = inc(i)) {
+ Object e = items[i];
+ sb.append(e == this ? "(this Collection)" : e);
+ if (--k == 0)
+ return sb.append(']').toString();
+ sb.append(',').append(' ');
+ }
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Atomically removes all of the elements from this queue.
+ * The queue will be empty after this call returns.
+ */
+ public void clear() {
+ final Object[] items = this.items;
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ for (int i = takeIndex, k = count; k > 0; i = inc(i), k--)
+ items[i] = null;
+ count = 0;
+ putIndex = 0;
+ takeIndex = 0;
+ notFull.signalAll();
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * @throws UnsupportedOperationException {@inheritDoc}
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ public int drainTo(Collection<? super E> c) {
+ checkNotNull(c);
+ if (c == this)
+ throw new IllegalArgumentException();
+ final Object[] items = this.items;
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ int i = takeIndex;
+ int n = 0;
+ int max = count;
+ while (n < max) {
+ c.add(this.<E>cast(items[i]));
+ items[i] = null;
+ i = inc(i);
+ ++n;
+ }
+ if (n > 0) {
+ count = 0;
+ putIndex = 0;
+ takeIndex = 0;
+ notFull.signalAll();
+ }
+ return n;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * @throws UnsupportedOperationException {@inheritDoc}
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ public int drainTo(Collection<? super E> c, int maxElements) {
+ checkNotNull(c);
+ if (c == this)
+ throw new IllegalArgumentException();
+ if (maxElements <= 0)
+ return 0;
+ final Object[] items = this.items;
+ final ReentrantLock lock = this.lock;
+ lock.lock();
+ try {
+ int i = takeIndex;
+ int n = 0;
+ int max = (maxElements < count) ? maxElements : count;
+ while (n < max) {
+ c.add(this.<E>cast(items[i]));
+ items[i] = null;
+ i = inc(i);
+ ++n;
+ }
+ if (n > 0) {
+ count -= n;
+ takeIndex = i;
+ notFull.signalAll();
+ }
+ return n;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Returns an iterator over the elements in this queue in proper sequence.
+ * The elements will be returned in order from first (head) to last (tail).
+ *
+ * <p>The returned {@code Iterator} is a "weakly consistent" iterator that
+ * will never throw {@link java.util.ConcurrentModificationException
+ * ConcurrentModificationException},
+ * and guarantees to traverse elements as they existed upon
+ * construction of the iterator, and may (but is not guaranteed to)
+ * reflect any modifications subsequent to construction.
+ *
+ * @return an iterator over the elements in this queue in proper sequence
+ */
+ public Iterator<E> iterator() {
+ return new Itr();
+ }
+
+ /**
+ * Iterator for Target. To maintain weak consistency
+ * with respect to puts and takes, we (1) read ahead one slot, so
+ * as to not report hasNext true but then not have an element to
+ * return -- however we later recheck this slot to use the most
+ * current value; (2) ensure that each array slot is traversed at
+ * most once (by tracking "remaining" elements); (3) skip over
+ * null slots, which can occur if takes race ahead of iterators.
+ * However, for circular array-based queues, we cannot rely on any
+ * well established definition of what it means to be weakly
+ * consistent with respect to interior removes since these may
+ * require slot overwrites in the process of sliding elements to
+ * cover gaps. So we settle for resiliency, operating on
+ * established apparent nexts, which may miss some elements that
+ * have moved between calls to next.
+ */
+ private class Itr implements Iterator<E> {
+ private int remaining; // Number of elements yet to be returned
+ private int nextIndex; // Index of element to be returned by next
+ private E nextItem; // Element to be returned by next call to next
+ private E lastItem; // Element returned by last call to next
+ private int lastRet; // Index of last element returned, or -1 if none
+
+ Itr() {
+ final ReentrantLock lock = InstrumentationTarget.this.lock;
+ lock.lock();
+ try {
+ lastRet = -1;
+ if ((remaining = count) > 0)
+ nextItem = itemAt(nextIndex = takeIndex);
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ public boolean hasNext() {
+ return remaining > 0;
+ }
+
+ public E next() {
+ final ReentrantLock lock = InstrumentationTarget.this.lock;
+ lock.lock();
+ try {
+ if (remaining <= 0)
+ throw new NoSuchElementException();
+ lastRet = nextIndex;
+ E x = itemAt(nextIndex); // check for fresher value
+ if (x == null) {
+ x = nextItem; // we are forced to report old value
+ lastItem = null; // but ensure remove fails
+ } else
+ lastItem = x;
+ while (--remaining > 0 && // skip over nulls
+ (nextItem = itemAt(nextIndex = inc(nextIndex))) == null)
+ ;
+ return x;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ public void remove() {
+ final ReentrantLock lock = InstrumentationTarget.this.lock;
+ lock.lock();
+ try {
+ int i = lastRet;
+ if (i == -1)
+ throw new IllegalStateException();
+ lastRet = -1;
+ E x = lastItem;
+ lastItem = null;
+ // only remove if item still at index
+ if (x != null && x == items[i]) {
+ boolean removingHead = (i == takeIndex);
+ removeAt(i);
+ if (!removingHead)
+ nextIndex = dec(nextIndex);
+ }
+ } finally {
+ lock.unlock();
+ }
+ }
+ }
+
+}
+
projects / javassist.git / commitdiff