*/
package org.opendaylight.yangtools.util;
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.Objects.requireNonNull;
+
import com.google.common.annotations.Beta;
-import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.UnmodifiableIterator;
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.reflect.Field;
+import java.util.AbstractMap.SimpleImmutableEntry;
import java.util.AbstractSet;
import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
-import java.util.Objects;
import java.util.Set;
-import javax.annotation.Nonnull;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
/**
* Implementation of the {@link Map} interface which stores a set of immutable mappings using a key-to-offset map and
* a backing array. This is useful for situations where the same key set is shared across a multitude of maps, as this
* class uses a global cache to share the key-to-offset mapping.
*
- * This map supports creation of value objects on the fly. To achieve that, subclasses should override {@link #valueToObject(Object)},
- * {@link #objectToValue(Object, Object)}, {@link #clone()} and {@link #toModifiableMap()} methods.
+ * <p>
+ * In case the set of keys is statically known, you can use {@link ImmutableOffsetMapTemplate} to efficiently create
+ * {@link ImmutableOffsetMap} instances.
*
* @param <K> the type of keys maintained by this map
* @param <V> the type of mapped values
*/
@Beta
-public class ImmutableOffsetMap<K, V> extends AbstractLazyValueMap<K, V> implements Cloneable, UnmodifiableMapPhase<K, V>, Serializable {
+public abstract class ImmutableOffsetMap<K, V> implements UnmodifiableMapPhase<K, V>, Serializable {
+ static final class Ordered<K, V> extends ImmutableOffsetMap<K, V> {
+ private static final long serialVersionUID = 1L;
+
+ Ordered(final ImmutableMap<K, Integer> offsets, final V[] objects) {
+ super(offsets, objects);
+ }
+
+ @Override
+ public @NonNull MutableOffsetMap<K, V> toModifiableMap() {
+ return MutableOffsetMap.orderedCopyOf(this);
+ }
+
+ @Override
+ void setFields(final List<K> keys, final V[] values) throws IOException {
+ setField(this, OFFSETS_FIELD, OffsetMapCache.orderedOffsets(keys));
+ setField(this, ARRAY_FIELD, values);
+ }
+ }
+
+ static final class Unordered<K, V> extends ImmutableOffsetMap<K, V> {
+ private static final long serialVersionUID = 1L;
+
+ Unordered(final ImmutableMap<K, Integer> offsets, final V[] objects) {
+ super(offsets, objects);
+ }
+
+ @Override
+ public @NonNull MutableOffsetMap<K, V> toModifiableMap() {
+ return MutableOffsetMap.unorderedCopyOf(this);
+ }
+
+ @Override
+ void setFields(final List<K> keys, final V[] values) throws IOException {
+ final Map<K, Integer> newOffsets = OffsetMapCache.unorderedOffsets(keys);
+
+ setField(this, OFFSETS_FIELD, newOffsets);
+ setField(this, ARRAY_FIELD, OffsetMapCache.adjustedArray(newOffsets, keys, values));
+ }
+ }
+
private static final long serialVersionUID = 1L;
- private final Map<K, Integer> offsets;
- private final Object[] objects;
+ private final transient @NonNull ImmutableMap<K, Integer> offsets;
+ private final transient @NonNull V[] objects;
+ private transient int hashCode;
/**
* Construct a new instance backed by specified key-to-offset map and array of objects.
* @param objects Array of value object, may not be null. The array is stored as is, the caller
* is responsible for ensuring its contents remain unmodified.
*/
- ImmutableOffsetMap(@Nonnull final Map<K, Integer> offsets, @Nonnull final Object[] objects) {
- this.offsets = Preconditions.checkNotNull(offsets);
- this.objects = Preconditions.checkNotNull(objects);
- Preconditions.checkArgument(offsets.size() == objects.length);
+ ImmutableOffsetMap(final ImmutableMap<K, Integer> offsets, final V[] objects) {
+ this.offsets = requireNonNull(offsets);
+ this.objects = requireNonNull(objects);
+ checkArgument(offsets.size() == objects.length);
}
+ @Override
+ public abstract @NonNull MutableOffsetMap<K, V> toModifiableMap();
+
+ abstract void setFields(List<K> keys, V[] values) throws IOException;
+
/**
- * Construct a new instance based on some other instance.
+ * Create an {@link ImmutableOffsetMap} as a copy of an existing map. This is actually not completely true, as this
+ * method returns an {@link ImmutableMap} for empty and singleton inputs, as those are more memory-efficient. This
+ * method also recognizes {@link ImmutableOffsetMap} and {@link SharedSingletonMap} on input, and returns it back
+ * without doing anything else. It also recognizes {@link MutableOffsetMap} (as returned by
+ * {@link #toModifiableMap()}) and makes an efficient copy of its contents. All other maps are converted to an
+ * {@link ImmutableOffsetMap} with the same iteration order as input.
*
- * @param m Instance to share data with, may not be null.
+ * @param <K> the type of keys maintained by the map
+ * @param <V> the type of mapped values
+ * @param map Input map, may not be null.
+ * @return An isolated, immutable copy of the input map
+ * @throws NullPointerException if {@code map} or any of its elements is null.
*/
- protected ImmutableOffsetMap(@Nonnull final ImmutableOffsetMap<K, V> m) {
- this.offsets = m.offsets;
- this.objects = m.objects;
+ public static <K, V> @NonNull Map<K, V> orderedCopyOf(final @NonNull Map<K, V> map) {
+ final Map<K, V> common = commonCopy(map);
+ if (common != null) {
+ return common;
+ }
+
+ final int size = map.size();
+ if (size == 1) {
+ // Efficient single-entry implementation
+ final Entry<K, V> e = map.entrySet().iterator().next();
+ return SharedSingletonMap.orderedOf(e.getKey(), e.getValue());
+ }
+
+ final ImmutableMap<K, Integer> offsets = OffsetMapCache.orderedOffsets(map.keySet());
+ @SuppressWarnings("unchecked")
+ final V[] array = (V[]) new Object[offsets.size()];
+ for (Entry<K, V> e : map.entrySet()) {
+ array[offsets.get(e.getKey())] = e.getValue();
+ }
+
+ return new Ordered<>(offsets, array);
}
/**
- * Create an {@link ImmutableOffsetMap} as a copy of an existing map. This is actually not completely true,
- * as this method returns an {@link ImmutableMap} for empty and singleton inputs, as those are more memory-efficient.
- * This method also recognizes {@link ImmutableOffsetMap} on input, and returns it back without doing anything else.
- * It also recognizes {@link MutableOffsetMap} (as returned by {@link #toModifiableMap()}) and makes an efficient
- * copy of its contents. All other maps are converted to an {@link ImmutableOffsetMap} with the same iteration
- * order as input.
+ * Create an {@link ImmutableOffsetMap} as a copy of an existing map. This is actually not completely true, as this
+ * method returns an {@link ImmutableMap} for empty and singleton inputs, as those are more memory-efficient. This
+ * method also recognizes {@link ImmutableOffsetMap} and {@link SharedSingletonMap} on input, and returns it back
+ * without doing anything else. It also recognizes {@link MutableOffsetMap} (as returned by
+ * {@link #toModifiableMap()}) and makes an efficient copy of its contents. All other maps are converted to an
+ * {@link ImmutableOffsetMap}. Iterator order is not guaranteed to be retained.
*
- * @param m Input map, may not be null.
+ * @param <K> the type of keys maintained by the map
+ * @param <V> the type of mapped values
+ * @param map Input map, may not be null.
* @return An isolated, immutable copy of the input map
+ * @throws NullPointerException if {@code map} or any of its elements is null.
*/
- @Nonnull public static <K, V> Map<K, V> copyOf(@Nonnull final Map<K, V> m) {
- // Prevent a copy
- if (m instanceof ImmutableOffsetMap) {
- return m;
+ public static <K, V> @NonNull Map<K, V> unorderedCopyOf(final @NonNull Map<K, V> map) {
+ final Map<K, V> common = commonCopy(map);
+ if (common != null) {
+ return common;
}
- // Better-packed
- final int size = m.size();
- if (size == 0) {
- return ImmutableMap.of();
- }
- if (size == 1) {
- return ImmutableMap.copyOf(m);
+ if (map.size() == 1) {
+ // Efficient single-entry implementation
+ final Entry<K, V> e = map.entrySet().iterator().next();
+ return SharedSingletonMap.unorderedOf(e.getKey(), e.getValue());
}
- // Familiar and efficient
- if (m instanceof MutableOffsetMap) {
- return ((MutableOffsetMap<K, V>) m).toUnmodifiableMap();
- }
-
- final Map<K, Integer> offsets = OffsetMapCache.offsetsFor(m.keySet());
+ final ImmutableMap<K, Integer> offsets = OffsetMapCache.unorderedOffsets(map.keySet());
@SuppressWarnings("unchecked")
final V[] array = (V[]) new Object[offsets.size()];
- for (Entry<K, V> e : m.entrySet()) {
+ for (Entry<K, V> e : map.entrySet()) {
array[offsets.get(e.getKey())] = e.getValue();
}
- return new ImmutableOffsetMap<>(offsets, array);
+ return new Unordered<>(offsets, array);
+ }
+
+ private static <K, V> @Nullable Map<K, V> commonCopy(final @NonNull Map<K, V> map) {
+ // Prevent a copy. Note that ImmutableMap is not listed here because of its potentially larger keySet overhead.
+ if (map instanceof ImmutableOffsetMap || map instanceof SharedSingletonMap) {
+ return map;
+ }
+
+ // Familiar and efficient to copy
+ if (map instanceof MutableOffsetMap) {
+ return ((MutableOffsetMap<K, V>) map).toUnmodifiableMap();
+ }
+
+ if (map.isEmpty()) {
+ // Shares a single object
+ return ImmutableMap.of();
+ }
+
+ return null;
}
@Override
return offsets.isEmpty();
}
+ @Override
+ public final int hashCode() {
+ if (hashCode != 0) {
+ return hashCode;
+ }
+
+ int result = 0;
+ for (Entry<K, Integer> e : offsets.entrySet()) {
+ result += e.getKey().hashCode() ^ objects[e.getValue()].hashCode();
+ }
+
+ hashCode = result;
+ return result;
+ }
+
+ @Override
+ public final boolean equals(final Object obj) {
+ if (obj == this) {
+ return true;
+ }
+ if (!(obj instanceof Map)) {
+ return false;
+ }
+
+ if (obj instanceof ImmutableOffsetMap) {
+ final ImmutableOffsetMap<?, ?> om = (ImmutableOffsetMap<?, ?>) obj;
+
+ // If the offset match, the arrays have to match, too
+ if (offsets.equals(om.offsets)) {
+ return Arrays.deepEquals(objects, om.objects);
+ }
+ } else if (obj instanceof MutableOffsetMap) {
+ // Let MutableOffsetMap do the actual work.
+ return obj.equals(this);
+ }
+
+ final Map<?, ?> other = (Map<?, ?>)obj;
+
+ // Size and key sets have to match
+ if (size() != other.size() || !keySet().equals(other.keySet())) {
+ return false;
+ }
+
+ try {
+ // Ensure all objects are present
+ for (Entry<K, Integer> e : offsets.entrySet()) {
+ if (!objects[e.getValue()].equals(other.get(e.getKey()))) {
+ return false;
+ }
+ }
+ } catch (ClassCastException e) {
+ // Can be thrown by other.get() indicating we have incompatible key types
+ return false;
+ }
+
+ return true;
+ }
+
@Override
public final boolean containsKey(final Object key) {
return offsets.containsKey(key);
@Override
public final boolean containsValue(final Object value) {
- @SuppressWarnings("unchecked")
- final Object obj = valueToObject((V)value);
for (Object o : objects) {
- if (Objects.equals(obj, o)) {
+ if (value.equals(o)) {
return true;
}
}
return false;
}
- @SuppressWarnings("unchecked")
@Override
public final V get(final Object key) {
- final Integer offset = offsets.get(key);
- if (offset == null) {
- return null;
- }
-
- return objectToValue((K) key, objects[offset]);
+ Integer offset;
+ return (offset = offsets.get(key)) == null ? null : objects[offset];
}
@Override
}
@Override
+ public final V put(final K key, final V value) {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ @SuppressWarnings("checkstyle:parameterName")
public final void putAll(final Map<? extends K, ? extends V> m) {
throw new UnsupportedOperationException();
}
}
@Override
- public final Set<Entry<K, V>> entrySet() {
- return new EntrySet();
+ public final @NonNull Collection<V> values() {
+ return new ConstantArrayCollection<>(objects);
}
@Override
- public MutableOffsetMap<K, V> toModifiableMap() {
- return new MutableOffsetMap<>(this);
+ public final @NonNull Set<Entry<K, V>> entrySet() {
+ return new EntrySet();
}
@Override
- public ImmutableOffsetMap<K, V> clone() throws CloneNotSupportedException {
- return new ImmutableOffsetMap<>(this);
+ public final String toString() {
+ final StringBuilder sb = new StringBuilder("{");
+ final Iterator<K> it = offsets.keySet().iterator();
+ int offset = 0;
+ while (it.hasNext()) {
+ sb.append(it.next()).append('=').append(objects[offset++]);
+
+ if (it.hasNext()) {
+ sb.append(", ");
+ }
+ }
+
+ return sb.append('}').toString();
}
- Map<K, Integer> offsets() {
+ final @NonNull ImmutableMap<K, Integer> offsets() {
return offsets;
}
- Object[] objects() {
+ final @NonNull V[] objects() {
return objects;
}
private final class EntrySet extends AbstractSet<Entry<K, V>> {
@Override
- public Iterator<Entry<K, V>> iterator() {
+ public @NonNull Iterator<Entry<K, V>> iterator() {
final Iterator<Entry<K, Integer>> it = offsets.entrySet().iterator();
-
- return new UnmodifiableIterator<Entry<K, V>>() {
+ return new UnmodifiableIterator<>() {
@Override
public boolean hasNext() {
return it.hasNext();
@Override
public Entry<K, V> next() {
final Entry<K, Integer> e = it.next();
- return new SimpleEntry<>(e.getKey(), objectToValue(e.getKey(), objects[e.getValue()]));
+ return new SimpleImmutableEntry<>(e.getKey(), objects[e.getValue()]);
}
};
}
private static final Field OFFSETS_FIELD = fieldFor("offsets");
private static final Field ARRAY_FIELD = fieldFor("objects");
- private static Field fieldFor(final String name) {
+ private static @NonNull Field fieldFor(final @NonNull String name) {
final Field f;
try {
f = ImmutableOffsetMap.class.getDeclaredField(name);
return f;
}
- private void setField(final Field field, final Object value) throws IOException {
+ @SuppressFBWarnings(value = "UPM_UNCALLED_PRIVATE_METHOD",
+ justification = "https://github.com/spotbugs/spotbugs/issues/811")
+ private static void setField(final @NonNull ImmutableOffsetMap<?, ?> map, final @NonNull Field field,
+ final Object value) throws IOException {
try {
- field.set(this, value);
+ field.set(map, value);
} catch (IllegalArgumentException | IllegalAccessException e) {
throw new IOException("Failed to set field " + field, e);
}
}
@SuppressWarnings("unchecked")
- private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
+ private void readObject(final @NonNull ObjectInputStream in) throws IOException, ClassNotFoundException {
final int s = in.readInt();
final List<K> keys = new ArrayList<>(s);
values[i] = (V)in.readObject();
}
- setField(OFFSETS_FIELD, OffsetMapCache.offsetsFor(keys));
- setField(ARRAY_FIELD, values);
+ setFields(keys, values);
}
}
Code Review / yangtools.git / blobdiff