import com.google.common.annotations.Beta;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
+import com.google.common.base.Verify;
import com.google.common.collect.ImmutableMap;
import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.ArrayList;
import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
import java.util.ConcurrentModificationException;
+import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
+import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
* @param <V> the type of mapped values
*/
@Beta
-public final class MutableOffsetMap<K, V> extends AbstractMap<K, V> implements Cloneable, ModifiableMapPhase<K, V> {
+public abstract class MutableOffsetMap<K, V> extends AbstractMap<K, V> implements Cloneable, ModifiableMapPhase<K, V> {
+ static final class Ordered<K, V> extends MutableOffsetMap<K, V> {
+ Ordered() {
+ super(new LinkedHashMap<K, V>());
+ }
+
+ Ordered(final Map<K, V> source) {
+ super(OffsetMapCache.orderedOffsets(source.keySet()), source, new LinkedHashMap<K, V>());
+ }
+
+ Ordered(final Map<K, Integer> offsets, final V[] objects) {
+ super(offsets, objects, new LinkedHashMap<K, V>());
+ }
+
+ @Override
+ Object removedObject() {
+ return REMOVED;
+ }
+
+ @Override
+ UnmodifiableMapPhase<K, V> modifiedMap(final List<K> keys, final V[] objects) {
+ return new ImmutableOffsetMap.Ordered<>(OffsetMapCache.orderedOffsets(keys), objects);
+ }
+
+ @Override
+ UnmodifiableMapPhase<K, V> unmodifiedMap(final Map<K, Integer> offsets, final V[] objects) {
+ return new ImmutableOffsetMap.Ordered<>(offsets, objects);
+ }
+ }
+
private static final Object[] EMPTY_ARRAY = new Object[0];
+ private static final Object REMOVED = new Object();
private final Map<K, Integer> offsets;
- private final Map<K, V> newKeys;
- private V[] objects;
+ private HashMap<K, V> newKeys;
+ private Object[] objects;
private int removed = 0;
private transient volatile int modCount;
private boolean needClone = true;
- public MutableOffsetMap() {
- this(Collections.<K>emptySet());
+ MutableOffsetMap(final Map<K, Integer> offsets, final V[] objects, final HashMap<K, V> newKeys) {
+ Verify.verify(newKeys.isEmpty());
+ this.offsets = Preconditions.checkNotNull(offsets);
+ this.objects = Preconditions.checkNotNull(objects);
+ this.newKeys = Preconditions.checkNotNull(newKeys);
}
@SuppressWarnings("unchecked")
- protected MutableOffsetMap(final Collection<K> keySet) {
- if (!keySet.isEmpty()) {
- removed = keySet.size();
- offsets = OffsetMapCache.offsetsFor(keySet);
- objects = (V[])new Object[removed];
- } else {
- offsets = ImmutableMap.of();
- objects = (V[])EMPTY_ARRAY;
- }
-
- this.newKeys = new LinkedHashMap<>();
- }
-
- protected MutableOffsetMap(final ImmutableOffsetMap<K, V> m) {
- this(m.offsets(), m.objects());
+ MutableOffsetMap(final HashMap<K, V> newKeys) {
+ this(ImmutableMap.<K, Integer>of(), (V[]) EMPTY_ARRAY, newKeys);
}
@SuppressWarnings("unchecked")
- protected MutableOffsetMap(final Map<K, V> m) {
- this(OffsetMapCache.offsetsFor(m.keySet()), (V[])m.values().toArray());
- }
+ MutableOffsetMap(final Map<K, Integer> offsets, final Map<K, V> source, final HashMap<K, V> newKeys) {
+ this(offsets, (V[]) new Object[offsets.size()], newKeys);
- protected MutableOffsetMap(final MutableOffsetMap<K, V> m) {
- this.offsets = m.offsets;
- this.objects = m.objects;
- this.newKeys = new LinkedHashMap<>(m.newKeys);
- this.removed = m.removed;
- }
+ for (Entry<K, V> e : source.entrySet()) {
+ objects[offsets.get(e.getKey())] = Preconditions.checkNotNull(e.getValue());
+ }
- private MutableOffsetMap(final Map<K, Integer> offsets, final V[] objects) {
- this.offsets = Preconditions.checkNotNull(offsets);
- this.objects = Preconditions.checkNotNull(objects);
- this.newKeys = new LinkedHashMap<>();
+ this.needClone = false;
}
public static <K, V> MutableOffsetMap<K, V> copyOf(final Map<K, V> m) {
return ((MutableOffsetMap<K, V>) m).clone();
}
if (m instanceof ImmutableOffsetMap) {
- return ((ImmutableOffsetMap<K, V>) m).toModifiableMap();
+ final ImmutableOffsetMap<K, V> om = (ImmutableOffsetMap<K, V>) m;
+ return new MutableOffsetMap.Ordered<>(om.offsets(), om.objects());
}
- return new MutableOffsetMap<>(m);
+ return new MutableOffsetMap.Ordered<>(m);
}
- public static <K, V> MutableOffsetMap<K, V> forOffsets(final Map<K, Integer> offsets) {
- @SuppressWarnings("unchecked")
- final V[] objects = (V[]) new Object[offsets.size()];
- return new MutableOffsetMap<>(offsets, objects);
+ public static <K, V> MutableOffsetMap<K, V> of() {
+ return new MutableOffsetMap.Ordered<>();
}
- public static <K, V> MutableOffsetMap<K, V> forKeySet(final Collection<K> keySet) {
- return forOffsets(OffsetMapCache.offsetsFor(keySet));
- }
+ abstract Object removedObject();
+ abstract UnmodifiableMapPhase<K, V> modifiedMap(List<K> keys, V[] objects);
+ abstract UnmodifiableMapPhase<K, V> unmodifiedMap(Map<K, Integer> offsets, V[] objects);
@Override
- public int size() {
+ public final int size() {
return offsets.size() + newKeys.size() - removed;
}
@Override
- public boolean isEmpty() {
+ public final boolean isEmpty() {
return size() == 0;
}
@Override
- public boolean containsKey(final Object key) {
+ public final boolean containsKey(final Object key) {
final Integer offset = offsets.get(key);
- return offset == null ? newKeys.containsKey(key) : objects[offset] != null;
+ if (offset != null) {
+ final Object obj = objects[offset];
+ if (!REMOVED.equals(obj)) {
+ return obj != null;
+ }
+ }
+
+ return newKeys.containsKey(key);
}
@Override
- public V get(final Object key) {
+ public final V get(final Object key) {
final Integer offset = offsets.get(key);
- return offset == null ? newKeys.get(key) : objects[offset];
+ if (offset != null) {
+ final Object obj = objects[offset];
+
+ /*
+ * This is a bit tricky: Ordered will put REMOVED to removed objects to retain strict insertion order.
+ * Unordered will add null, indicating that the slot may be reused in future. Hence if we see a REMOVED
+ * marker, we need to fall back to checking with new keys.
+ */
+ if (!REMOVED.equals(obj)) {
+ @SuppressWarnings("unchecked")
+ final V ret = (V)obj;
+ return ret;
+ }
+ }
+
+ return newKeys.get(key);
}
private void cloneArray() {
}
@Override
- public V put(final K key, final V value) {
+ public final V put(final K key, final V value) {
Preconditions.checkNotNull(value);
final Integer offset = offsets.get(Preconditions.checkNotNull(key));
- if (offset == null) {
- final V ret = newKeys.put(key, value);
- if (ret == null) {
- modCount++;
+ if (offset != null) {
+ final Object obj = objects[offset];
+
+ /*
+ * Put which can potentially replace something in objects. Replacing an object does not cause iterators
+ * to be invalidated and does follow insertion order (since it is not a fresh insert). If the object has
+ * been removed, we fall back to newKeys.
+ */
+ if (!REMOVED.equals(obj)) {
+ @SuppressWarnings("unchecked")
+ final V ret = (V)obj;
+
+ cloneArray();
+ objects[offset] = value;
+ if (ret == null) {
+ modCount++;
+ removed--;
+ }
+
+ return ret;
}
- return ret;
}
- cloneArray();
- final V ret = objects[offset];
- objects[offset] = value;
+ final V ret = newKeys.put(key, value);
if (ret == null) {
modCount++;
- removed--;
}
-
return ret;
}
@Override
- public V remove(final Object key) {
+ public final V remove(final Object key) {
final Integer offset = offsets.get(key);
- if (offset == null) {
- final V ret = newKeys.remove(key);
- if (ret != null) {
- modCount++;
+ if (offset != null) {
+ final Object obj = objects[offset];
+
+ /*
+ * A previous remove() may have indicated that the objects slot cannot be reused. In that case we need
+ * to fall back to checking with newKeys.
+ */
+ if (!REMOVED.equals(obj)) {
+ cloneArray();
+
+ @SuppressWarnings("unchecked")
+ final V ret = (V)obj;
+ objects[offset] = removedObject();
+ if (ret != null) {
+ modCount++;
+ removed++;
+ }
+ return ret;
}
- return ret;
}
- cloneArray();
- final V ret = objects[offset];
- objects[offset] = null;
+ final V ret = newKeys.remove(key);
if (ret != null) {
modCount++;
- removed++;
}
return ret;
}
@Override
- public void clear() {
+ public final void clear() {
if (size() != 0) {
newKeys.clear();
cloneArray();
- Arrays.fill(objects, null);
+ Arrays.fill(objects, removedObject());
removed = objects.length;
modCount++;
}
}
@Override
- public Set<Entry<K, V>> entrySet() {
+ public final Set<Entry<K, V>> entrySet() {
return new EntrySet();
}
@Override
public Map<K, V> toUnmodifiableMap() {
- if (newKeys.isEmpty() && removed == 0) {
+ if (removed == 0 && newKeys.isEmpty()) {
// Make sure next modification clones the array, as we leak it to the map we return.
needClone = true;
+
+ // We have ended up with no removed objects, hence this cast is safe
+ @SuppressWarnings("unchecked")
+ final V[] values = (V[])objects;
+
/*
* TODO: we could track the ImmutableOffsetMap from which this one was instantiated and if we do not
* perform any modifications, just return the original instance. The trade-off is increased complexity
* and an additional field in this class.
*/
- return new ImmutableOffsetMap.Ordered<>(offsets, objects);
+ return unmodifiedMap(offsets, values);
}
final int s = size();
return ImmutableMap.of();
}
if (s == 1) {
- return ImmutableMap.copyOf(this);
+ return SharedSingletonMap.copyOf(this);
}
// Construct the set of keys
- final Collection<K> keyset = new ArrayList<>(s);
+ final List<K> keyset = new ArrayList<>(s);
if (removed != 0) {
if (removed != offsets.size()) {
for (Entry<K, Integer> e : offsets.entrySet()) {
- if (objects[e.getValue()] != null) {
+ final Object o = objects[e.getValue()];
+ if (o != null && !REMOVED.equals(o)) {
keyset.add(e.getKey());
}
}
if (removed != 0) {
if (removed != offsets.size()) {
for (Entry<K, Integer> e : offsets.entrySet()) {
- final V o = objects[e.getValue()];
- if (o != null) {
- values[i++] = o;
+ final Object o = objects[e.getValue()];
+ if (o != null && !REMOVED.equals(o)) {
+ @SuppressWarnings("unchecked")
+ final V v = (V) o;
+ values[i++] = v;
}
}
}
values[i++] = v;
}
- return new ImmutableOffsetMap.Ordered<>(OffsetMapCache.offsetsFor(keyset), values);
+ return modifiedMap(keyset, values);
}
+ @SuppressWarnings("unchecked")
@Override
public MutableOffsetMap<K, V> clone() {
- // FIXME: super.clone()
- return new MutableOffsetMap<K, V>(this);
+ final MutableOffsetMap<K, V> ret;
+
+ try {
+ ret = (MutableOffsetMap<K, V>) super.clone();
+ } catch (CloneNotSupportedException e) {
+ throw new IllegalStateException("Clone is expected to work", e);
+ }
+
+ ret.newKeys = (HashMap<K, V>) newKeys.clone();
+ ret.needClone = true;
+ return ret;
}
@Override
- public int hashCode() {
+ public final int hashCode() {
int result = 0;
for (Entry<K, Integer> e : offsets.entrySet()) {
}
@Override
- public boolean equals(final Object o) {
+ public final boolean equals(final Object o) {
if (o == this) {
return true;
}
// Ensure all objects are present
for (Entry<K, Integer> e : offsets.entrySet()) {
- final V v = objects[e.getValue()];
- if (v != null && !v.equals(other.get(e.getKey()))) {
+ final Object obj = objects[e.getValue()];
+ if (obj != null && !REMOVED.equals(obj) && !obj.equals(other.get(e.getKey()))) {
return false;
}
}
}
@Override
- public Set<K> keySet() {
+ public final Set<K> keySet() {
return new KeySet();
}
@VisibleForTesting
- boolean needClone() {
+ final boolean needClone() {
return needClone;
}
@VisibleForTesting
- Object array() {
+ final Object array() {
return objects;
}
@VisibleForTesting
- Object newKeys() {
+ final Object newKeys() {
return newKeys;
}
private void updateNextKey() {
while (oldIterator.hasNext()) {
final Entry<K, Integer> e = oldIterator.next();
- if (objects[e.getValue()] != null) {
+ final Object obj = objects[e.getValue()];
+ if (obj != null && !REMOVED.equals(obj)) {
nextKey = e.getKey();
return;
}
final Integer offset = offsets.get(currentKey);
if (offset != null) {
cloneArray();
- objects[offset] = null;
+ objects[offset] = removedObject();
removed++;
} else {
newIterator.remove();
Code Review / yangtools.git / blobdiff