package org.opendaylight.yangtools.triemap;
import static com.google.common.base.Preconditions.checkNotNull;
-import static com.google.common.base.Preconditions.checkState;
+import static org.opendaylight.yangtools.triemap.LookupResult.RESTART;
-import com.google.common.base.Verify;
-import com.google.common.collect.Iterators;
+import com.google.common.annotations.Beta;
import java.io.ObjectStreamException;
import java.io.Serializable;
import java.util.AbstractMap;
-import java.util.AbstractSet;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Iterator;
-import java.util.List;
-import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ConcurrentMap;
-import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
/***
* This is a port of Scala's TrieMap class from the Scala Collections library. This implementation does not support
* null keys nor null values.
*
- * @author Roman Levenstein <romixlev@gmail.com>
+ * @author Aleksandar Prokopec (original Scala implementation)
+ * @author Roman Levenstein (original Java 6 port)
+ * @author Robert Varga
*
- * @param <K>
- * @param <V>
+ * @param <K> the type of keys maintained by this map
+ * @param <V> the type of mapped values
*/
-@SuppressWarnings({"unchecked", "rawtypes", "unused"})
-public final class TrieMap<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K,V>, Serializable {
- private static final AtomicReferenceFieldUpdater<TrieMap, Object> ROOT_UPDATER =
- AtomicReferenceFieldUpdater.newUpdater(TrieMap.class, Object.class, "root");
+@Beta
+public abstract class TrieMap<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K,V>, Serializable {
private static final long serialVersionUID = 1L;
- /**
- * EntrySet
- */
- private final EntrySet entrySet = new EntrySet();
private final Equivalence<? super K> equiv;
- private final boolean readOnly;
-
- private volatile Object root;
- private TrieMap(final INode<K, V> r, final Equivalence<? super K> equiv, final boolean readOnly) {
- this.root = r;
- this.equiv = equiv;
- this.readOnly = readOnly;
- }
+ private AbstractEntrySet<K, V> entrySet;
+ private AbstractKeySet<K> keySet;
TrieMap(final Equivalence<? super K> equiv) {
- this(newRootNode(), equiv, false);
- }
-
- public TrieMap() {
- this(Equivalence.equals());
- }
-
- /* internal methods */
-
- final Equivalence<? super K> equiv() {
- return equiv;
- }
-
- private static <K,V> INode<K, V> newRootNode() {
- final Gen gen = new Gen();
- return new INode<>(gen, new CNode<>(gen));
- }
-
- final boolean CAS_ROOT(final Object ov, final Object nv) {
- checkState(!readOnly, "Attempted to modify a read-only snapshot");
- return ROOT_UPDATER.compareAndSet (this, ov, nv);
- }
-
- // FIXME: abort = false by default
- final INode<K, V> readRoot(final boolean abort) {
- return RDCSS_READ_ROOT(abort);
- }
-
- final INode<K, V> readRoot() {
- return RDCSS_READ_ROOT(false);
- }
-
- final INode<K, V> RDCSS_READ_ROOT() {
- return RDCSS_READ_ROOT(false);
- }
-
- final INode<K, V> RDCSS_READ_ROOT(final boolean abort) {
- final Object r = /* READ */root;
- if (r instanceof INode) {
- return (INode<K, V>) r;
- }
-
- checkState(r instanceof RDCSS_Descriptor, "Unhandled root %s", r);
- return RDCSS_Complete(abort);
- }
-
- private INode<K, V> RDCSS_Complete(final boolean abort) {
- while (true) {
- final Object r = /* READ */root;
- if (r instanceof INode) {
- return (INode<K, V>) r;
- }
-
- checkState(r instanceof RDCSS_Descriptor, "Unhandled root %s", r);
- final RDCSS_Descriptor<K, V> desc = (RDCSS_Descriptor<K, V>) r;
- final INode<K, V> ov = desc.old;
- final MainNode<K, V> exp = desc.expectedmain;
- final INode<K, V> nv = desc.nv;
-
- if (abort) {
- if (CAS_ROOT(desc, ov)) {
- return ov;
- }
-
- // Tail recursion: return RDCSS_Complete(abort);
- continue;
- }
-
- final MainNode<K, V> oldmain = ov.gcasRead(this);
- if (oldmain == exp) {
- if (CAS_ROOT(desc, nv)) {
- desc.committed = true;
- return nv;
- }
-
- // Tail recursion: return RDCSS_Complete(abort);
- continue;
- }
-
- if (CAS_ROOT(desc, ov)) {
- return ov;
- }
-
- // Tail recursion: return RDCSS_Complete(abort);
- }
- }
-
- private boolean RDCSS_ROOT(final INode<K, V> ov, final MainNode<K, V> expectedmain, final INode<K, V> nv) {
- final RDCSS_Descriptor<K, V> desc = new RDCSS_Descriptor<> (ov, expectedmain, nv);
- if (CAS_ROOT(ov, desc)) {
- RDCSS_Complete(false);
- return /* READ */desc.committed;
- }
-
- return false;
- }
-
- private void inserthc(final K k, final int hc, final V v) {
- // TODO: this is called from serialization only, which means we should not be observing any races,
- // hence we should not need to pass down the entire tree, just equality (I think).
- final INode<K, V> r = RDCSS_READ_ROOT();
- final boolean success = r.rec_insert(k, v, hc, 0, null, this);
- Verify.verify(success, "Concurrent modification during serialization of map %s", this);
- }
-
- private Optional<V> insertifhc(final K k, final int hc, final V v, final Object cond) {
- Optional<V> res;
- do {
- // Keep looping as long as we do not get a reply
- res = RDCSS_READ_ROOT().rec_insertif(k, v, hc, cond, 0, null, this);
- } while (res == null);
-
- return res;
- }
-
- private V lookuphc(final K k, final int hc) {
- Object res;
- do {
- // Keep looping as long as RESTART is being indicated
- res = RDCSS_READ_ROOT().rec_lookup(k, hc, 0, null, this);
- } while (INode.RESTART.equals(res));
-
- return (V) res;
+ this.equiv = equiv;
}
- private Optional<V> removehc(final K k, final V v, final int hc) {
- Optional<V> res;
- do {
- // Keep looping as long as we do not get a reply
- res = RDCSS_READ_ROOT().rec_remove(k, v, hc, 0, null, this);
- } while (res == null);
-
- return res;
+ public static <K, V> TrieMap<K, V> create() {
+ return new MutableTrieMap<>(Equivalence.equals());
}
- /**
- * Ensure this instance is read-write, throw UnsupportedOperationException
- * otherwise. Used by Map-type methods for quick check.
- */
- private void ensureReadWrite() {
- if (readOnly) {
- throw new UnsupportedOperationException("Attempted to modify a read-only view");
- }
- }
-
- boolean isReadOnly() {
- return readOnly;
- }
-
- /* public methods */
-
/**
* Returns a snapshot of this TrieMap. This operation is lock-free and
* linearizable.
* distributed across all the threads doing updates or accesses subsequent
* to the snapshot creation.
*/
- public TrieMap<K, V> snapshot() {
- while (true) {
- final INode<K, V> r = RDCSS_READ_ROOT();
- final MainNode<K, V> expmain = r.gcasRead(this);
- if (RDCSS_ROOT(r, expmain, r.copyToGen(new Gen(), this))) {
- return new TrieMap<> (r.copyToGen(new Gen(), this), equiv, readOnly);
- }
-
- // Tail recursion: return snapshot();
- }
- }
+ public abstract TrieMap<K, V> mutableSnapshot();
/**
* Returns a read-only snapshot of this TrieMap. This operation is lock-free
*
* This method is used by other methods such as `size` and `iterator`.
*/
- public TrieMap<K, V> readOnlySnapshot() {
- // Is it a snapshot of a read-only snapshot?
- if (readOnly) {
- return this;
- }
-
- while (true) {
- final INode<K, V> r = RDCSS_READ_ROOT();
- final MainNode<K, V> expmain = r.gcasRead(this);
- if (RDCSS_ROOT(r, expmain, r.copyToGen (new Gen(), this))) {
- return new TrieMap<>(r, equiv, true);
- }
+ public abstract ImmutableTrieMap<K, V> immutableSnapshot();
- // Tail recursion: return readOnlySnapshot();
- }
+ @Override
+ public final boolean containsKey(final Object key) {
+ return get(key) != null;
}
@Override
- public void clear() {
- boolean success;
- do {
- final INode<K, V> r = RDCSS_READ_ROOT();
- success = RDCSS_ROOT(r, r.gcasRead(this), newRootNode());
- } while (!success);
+ public final boolean containsValue(final Object value) {
+ return super.containsValue(checkNotNull(value));
}
- int computeHash(final K k) {
- return equiv.hash(k);
+ @Override
+ public final Set<Entry<K, V>> entrySet() {
+ AbstractEntrySet<K, V> ret = entrySet;
+ if (ret == null) {
+ entrySet = ret = createEntrySet();
+ }
+ return ret;
}
- boolean equal(final K k1, final K k2) {
- return equiv.equivalent(k1, k2);
+ @Override
+ public final Set<K> keySet() {
+ AbstractKeySet<K> ret = keySet;
+ if (ret == null) {
+ keySet = ret = createKeySet();
+ }
+ return ret;
}
@Override
- public V get(final Object key) {
+ public final V get(final Object key) {
+ @SuppressWarnings("unchecked")
final K k = (K) checkNotNull(key);
return lookuphc(k, computeHash(k));
}
@Override
- public V put(final K key, final V value) {
- ensureReadWrite();
- final K k = checkNotNull(key);
- return insertifhc(k, computeHash(k), checkNotNull(value), null).orElse(null);
- }
+ public abstract void clear();
- void add(final K key, final V value) {
- final K k = checkNotNull(key);
- inserthc(k, computeHash(k), checkNotNull(value));
- }
+ @Override
+ public abstract V put(K key, V value);
@Override
- public V remove(final Object key) {
- ensureReadWrite();
- final K k = (K) checkNotNull(key);
- return removehc(k, (V) null, computeHash(k)).orElse(null);
- }
+ public abstract V putIfAbsent(K key, V value);
@Override
- public V putIfAbsent(final K key, final V value) {
- ensureReadWrite();
- final K k = checkNotNull(key);
- return insertifhc(k, computeHash(k), checkNotNull(value), INode.KEY_ABSENT).orElse(null);
- }
+ public abstract V remove(Object key);
@Override
- public boolean remove(final Object key, final Object v) {
- ensureReadWrite();
- final K k = (K) checkNotNull(key);
- return removehc(k, (V) checkNotNull(v), computeHash(k)).isPresent();
- }
+ public abstract boolean remove(Object key, Object value);
@Override
- public boolean replace(final K key, final V oldValue, final V newValue) {
- ensureReadWrite();
- final K k = checkNotNull(key);
- return insertifhc(k, computeHash(k), checkNotNull(newValue), checkNotNull(oldValue)).isPresent();
- }
+ public abstract boolean replace(K key, V oldValue, V newValue);
@Override
- public V replace(final K key, final V value) {
- ensureReadWrite();
- final K k = checkNotNull(key);
- return insertifhc (k, computeHash(k), checkNotNull(value), INode.KEY_PRESENT).orElse(null);
- }
+ public abstract V replace(K key, V value);
+
+ @Override
+ public abstract int size();
+
+ /* internal methods implemented by subclasses */
+
+ abstract AbstractEntrySet<K, V> createEntrySet();
+
+ abstract AbstractKeySet<K> createKeySet();
+
+ abstract boolean isReadOnly();
+
+ abstract INode<K, V> RDCSS_READ_ROOT(boolean abort);
- /***
+ /**
* Return an iterator over a TrieMap.
*
* If this is a read-only snapshot, it would return a read-only iterator.
*
* @return
*/
- Iterator<Entry<K, V>> iterator() {
- return readOnly ? new TrieMapReadOnlyIterator<>(0, this) : new TrieMapIterator<>(0, this);
- }
+ abstract AbstractIterator<K, V> iterator();
+
+ /* internal methods provided for subclasses */
- /***
+ /**
* Return an iterator over a TrieMap.
* This is a read-only iterator.
*
* @return
*/
- Iterator<Entry<K, V>> readOnlyIterator() {
- return new TrieMapReadOnlyIterator<>(0, readOnly ? this : readOnlySnapshot());
+ final ImmutableIterator<K, V> immutableIterator() {
+ return new ImmutableIterator<>(immutableSnapshot());
}
- private int cachedSize() {
- INode<K, V> r = RDCSS_READ_ROOT ();
- return r.cachedSize (this);
+ @SuppressWarnings("null")
+ static <V> V toNullable(final Optional<V> opt) {
+ return opt.orElse(null);
}
- @Override
- public int size() {
- return readOnly ? cachedSize() : readOnlySnapshot().size();
+ final int computeHash(final K k) {
+ return equiv.hash(k);
}
- @Override
- public boolean containsKey(final Object key) {
- return get(key) != null;
+ final Object writeReplace() throws ObjectStreamException {
+ return new SerializationProxy(immutableSnapshot(), isReadOnly());
}
- @Override
- public Set<Entry<K, V>> entrySet() {
- return entrySet;
- }
+ /* package-protected utility methods */
- private Object writeReplace() throws ObjectStreamException {
- return new ExternalForm(this);
+ final Equivalence<? super K> equiv() {
+ return equiv;
}
- private static final class RDCSS_Descriptor<K, V> {
- INode<K, V> old;
- MainNode<K, V> expectedmain;
- INode<K, V> nv;
- volatile boolean committed = false;
-
- RDCSS_Descriptor (final INode<K, V> old, final MainNode<K, V> expectedmain, final INode<K, V> nv) {
- this.old = old;
- this.expectedmain = expectedmain;
- this.nv = nv;
- }
+ final INode<K, V> readRoot() {
+ return RDCSS_READ_ROOT(false);
}
- /***
- * This iterator is a read-only one and does not allow for any update
- * operations on the underlying data structure.
- *
- * @param <K>
- * @param <V>
- */
- private static final class TrieMapReadOnlyIterator<K, V> extends TrieMapIterator<K, V> {
- TrieMapReadOnlyIterator (final int level, final TrieMap<K, V> ct, final boolean mustInit) {
- super (level, ct, mustInit);
- }
-
- TrieMapReadOnlyIterator (final int level, final TrieMap<K, V> ct) {
- this (level, ct, true);
- }
- @Override
- void initialize () {
- assert (ct.isReadOnly ());
- super.initialize ();
- }
-
- @Override
- public void remove () {
- throw new UnsupportedOperationException ("Operation not supported for read-only iterators");
- }
-
- @Override
- Entry<K, V> nextEntry(final Entry<K, V> rr) {
- // Return non-updatable entry
- return rr;
- }
+ // FIXME: abort = false by default
+ final INode<K, V> readRoot(final boolean abort) {
+ return RDCSS_READ_ROOT(abort);
}
- private static class TrieMapIterator<K, V> implements Iterator<Entry<K, V>> {
- private int level;
- protected TrieMap<K, V> ct;
- private final boolean mustInit;
- private final BasicNode[][] stack = new BasicNode[7][];
- private final int[] stackpos = new int[7];
- private int depth = -1;
- private Iterator<Entry<K, V>> subiter = null;
- private KVNode<K, V> current = null;
- private Entry<K, V> lastReturned = null;
-
- TrieMapIterator (final int level, final TrieMap<K, V> ct, final boolean mustInit) {
- this.level = level;
- this.ct = ct;
- this.mustInit = mustInit;
- if (this.mustInit) {
- initialize ();
- }
- }
-
- TrieMapIterator (final int level, final TrieMap<K, V> ct) {
- this (level, ct, true);
- }
-
-
- @Override
- public boolean hasNext() {
- return (current != null) || (subiter != null);
- }
-
- @Override
- public Entry<K, V> next() {
- if (!hasNext()) {
- throw new NoSuchElementException();
- }
-
- Entry<K, V> r = null;
- if (subiter != null) {
- r = subiter.next ();
- checkSubiter ();
- } else {
- r = current.kvPair ();
- advance ();
- }
-
- lastReturned = r;
- if (r != null) {
- final Entry<K, V> rr = r;
- return nextEntry(rr);
- }
- return r;
- }
-
- Entry<K, V> nextEntry(final Entry<K, V> rr) {
- return new Entry<K, V>() {
- private V updated = null;
-
- @Override
- public K getKey () {
- return rr.getKey ();
- }
-
- @Override
- public V getValue () {
- return (updated == null) ? rr.getValue (): updated;
- }
-
- @Override
- public V setValue (final V value) {
- updated = value;
- return ct.replace (getKey (), value);
- }
- };
- }
-
- private void readin (final INode<K, V> in) {
- MainNode<K, V> m = in.gcasRead (ct);
- if (m instanceof CNode) {
- CNode<K, V> cn = (CNode<K, V>) m;
- depth += 1;
- stack [depth] = cn.array;
- stackpos [depth] = -1;
- advance ();
- } else if (m instanceof TNode) {
- current = (TNode<K, V>) m;
- } else if (m instanceof LNode) {
- subiter = ((LNode<K, V>) m).iterator();
- checkSubiter ();
- } else if (m == null) {
- current = null;
- }
- }
-
- // @inline
- private void checkSubiter () {
- if (!subiter.hasNext ()) {
- subiter = null;
- advance ();
- }
- }
-
- // @inline
- void initialize () {
-// assert (ct.isReadOnly ());
- INode<K, V> r = ct.RDCSS_READ_ROOT ();
- readin (r);
- }
-
- void advance () {
- if (depth >= 0) {
- int npos = stackpos [depth] + 1;
- if (npos < stack [depth].length) {
- stackpos [depth] = npos;
- BasicNode elem = stack [depth] [npos];
- if (elem instanceof SNode) {
- current = (SNode<K, V>) elem;
- } else if (elem instanceof INode) {
- readin ((INode<K, V>) elem);
- }
- } else {
- depth -= 1;
- advance ();
- }
- } else {
- current = null;
- }
- }
-
- protected TrieMapIterator<K, V> newIterator (final int _lev, final TrieMap<K, V> _ct, final boolean _mustInit) {
- return new TrieMapIterator<> (_lev, _ct, _mustInit);
- }
-
- protected void dupTo (final TrieMapIterator<K, V> it) {
- it.level = this.level;
- it.ct = this.ct;
- it.depth = this.depth;
- it.current = this.current;
-
- // these need a deep copy
- System.arraycopy (this.stack, 0, it.stack, 0, 7);
- System.arraycopy (this.stackpos, 0, it.stackpos, 0, 7);
-
- // this one needs to be evaluated
- if (this.subiter == null) {
- it.subiter = null;
- } else {
- List<Entry<K, V>> lst = toList (this.subiter);
- this.subiter = lst.iterator ();
- it.subiter = lst.iterator ();
- }
- }
-
- // /** Returns a sequence of iterators over subsets of this iterator.
- // * It's used to ease the implementation of splitters for a parallel
- // version of the TrieMap.
- // */
- // protected def subdivide(): Seq[Iterator[(K, V)]] = if (subiter ne
- // null) {
- // // the case where an LNode is being iterated
- // val it = subiter
- // subiter = null
- // advance()
- // this.level += 1
- // Seq(it, this)
- // } else if (depth == -1) {
- // this.level += 1
- // Seq(this)
- // } else {
- // var d = 0
- // while (d <= depth) {
- // val rem = stack(d).length - 1 - stackpos(d)
- // if (rem > 0) {
- // val (arr1, arr2) = stack(d).drop(stackpos(d) + 1).splitAt(rem / 2)
- // stack(d) = arr1
- // stackpos(d) = -1
- // val it = newIterator(level + 1, ct, false)
- // it.stack(0) = arr2
- // it.stackpos(0) = -1
- // it.depth = 0
- // it.advance() // <-- fix it
- // this.level += 1
- // return Seq(this, it)
- // }
- // d += 1
- // }
- // this.level += 1
- // Seq(this)
- // }
-
- private List<Entry<K, V>> toList (final Iterator<Entry<K, V>> it) {
- ArrayList<Entry<K, V>> list = new ArrayList<> ();
- while (it.hasNext ()) {
- list.add (it.next());
- }
- return list;
- }
-
- void printDebug () {
- System.out.println ("ctrie iterator");
- System.out.println (Arrays.toString (stackpos));
- System.out.println ("depth: " + depth);
- System.out.println ("curr.: " + current);
- // System.out.println(stack.mkString("\n"));
- }
-
- @Override
- public void remove() {
- checkState(lastReturned != null);
- ct.remove(lastReturned.getKey());
- lastReturned = null;
- }
+ final INode<K, V> RDCSS_READ_ROOT() {
+ return RDCSS_READ_ROOT(false);
}
- /***
- * Support for EntrySet operations required by the Map interface
- */
- private final class EntrySet extends AbstractSet<Entry<K, V>> {
- @Override
- public Iterator<Entry<K, V>> iterator() {
- return TrieMap.this.iterator ();
- }
-
- @Override
- public final boolean contains(final Object o) {
- if (!(o instanceof Entry)) {
- return false;
- }
-
- final Entry<?, ?> e = (Entry<?, ?>) o;
- if (e.getKey() == null) {
- return false;
- }
- final V v = get(e.getKey());
- return v != null && v.equals(e.getValue());
- }
+ final boolean equal(final K k1, final K k2) {
+ return equiv.equivalent(k1, k2);
+ }
- @Override
- public final boolean remove(final Object o) {
- if (!(o instanceof Entry)) {
- return false;
- }
- final Entry<?, ?> e = (Entry<K, V>) o;
- final Object key = e.getKey();
- if (key == null) {
- return false;
- }
- final Object value = e.getValue();
- if (value == null) {
- return false;
- }
-
- return TrieMap.this.remove(key, value);
- }
+ /* private implementation methods */
- @Override
- public final int size () {
- return Iterators.size(iterator());
- }
+ @SuppressWarnings("unchecked")
+ private V lookuphc(final K k, final int hc) {
+ Object res;
+ do {
+ // Keep looping as long as RESTART is being indicated
+ res = RDCSS_READ_ROOT().rec_lookup(k, hc, 0, null, this);
+ } while (res == RESTART);
- @Override
- public final void clear () {
- TrieMap.this.clear ();
- }
+ return (V) res;
}
}
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