package org.opendaylight.yangtools.yang.parser.stmt.reactor;
import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Verify.verify;
import static java.util.Objects.requireNonNull;
-import com.google.common.base.Preconditions;
import com.google.common.collect.AbstractIterator;
-import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterators;
import java.util.AbstractCollection;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.function.Consumer;
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
/**
* Simple integer-to-StatementContextBase map optimized for size and restricted in scope of operations. It does not
* implement {@link java.util.Map} for simplicity's sake.
*
+ * <p>
+ * Unlike other collections, this view does not detect concurrent modification. Iteration is performed in order of
+ * increasing offset. In face of concurrent modification, number of elements returned through iteration may not match
+ * the size reported via {@link Collection#size()}.
+ *
* @author Robert Varga
*/
-abstract class StatementMap {
+abstract class StatementMap extends AbstractCollection<AbstractResumedStatement<?, ?, ?>> {
private static final class Empty extends StatementMap {
+ private static final Iterator<AbstractResumedStatement<?, ?, ?>> EMPTY_ITERATOR;
+
+ static {
+ // This may look weird, but we really want to return two Iterator implementations from StatementMap, so that
+ // users have to deal with bimorphic invocation. Note that we want to invoke hasNext() here, as we want to
+ // initialize state to AbstractIterator.endOfData().
+ final Iterator<AbstractResumedStatement<?, ?, ?>> it = new Regular(0).iterator();
+ verify(!it.hasNext());
+ EMPTY_ITERATOR = it;
+ }
+
@Override
- StatementContextBase<?, ?, ?> get(final int index) {
+ AbstractResumedStatement<?, ?, ?> get(final int index) {
return null;
}
@Override
- StatementMap put(final int index, final StatementContextBase<?, ?, ?> object) {
- return index == 0 ? new Singleton(object) : new Regular(index, object);
+ StatementMap put(final int index, final AbstractResumedStatement<?, ?, ?> obj) {
+ return index == 0 ? new Singleton(obj) : new Regular(index, obj);
}
@Override
- Collection<StatementContextBase<?, ?, ?>> values() {
- return ImmutableList.of();
+ public int size() {
+ return 0;
}
@Override
- int size() {
+ StatementMap ensureCapacity(final int expectedLimit) {
+ return expectedLimit < 2 ? this : new Regular(expectedLimit);
+ }
+
+ @Override
+ int capacity() {
return 0;
}
+
+ @Override
+ public void forEach(final Consumer<? super AbstractResumedStatement<?, ?, ?>> action) {
+ // No-op
+ }
+
+ @Override
+ public Iterator<AbstractResumedStatement<?, ?, ?>> iterator() {
+ return EMPTY_ITERATOR;
+ }
}
private static final class Regular extends StatementMap {
- private StatementContextBase<?, ?, ?>[] elements;
+ private AbstractResumedStatement<?, ?, ?>[] elements;
+ private int size;
+
+ Regular(final int expectedLimit) {
+ elements = new AbstractResumedStatement<?, ?, ?>[expectedLimit];
+ }
- Regular(final int index, final StatementContextBase<?, ?, ?> object) {
- elements = new StatementContextBase<?, ?, ?>[index + 1];
+ Regular(final int index, final AbstractResumedStatement<?, ?, ?> object) {
+ this(index + 1, index, object);
+ }
+
+ Regular(final AbstractResumedStatement<?, ?, ?> object0, final int index,
+ final AbstractResumedStatement<?, ?, ?> object) {
+ this(index + 1, 0, object0);
elements[index] = requireNonNull(object);
+ size = 2;
}
- Regular(final StatementContextBase<?, ?, ?> object0, final int index,
- final StatementContextBase<?, ?, ?> object) {
- elements = new StatementContextBase<?, ?, ?>[index + 1];
- elements[0] = requireNonNull(object0);
+ Regular(final int expectedLimit, final int index, final AbstractResumedStatement<?, ?, ?> object) {
+ this(expectedLimit);
elements[index] = requireNonNull(object);
+ size = 1;
}
@Override
- StatementContextBase<?, ?, ?> get(final int index) {
- if (index >= elements.length) {
- return null;
- }
-
- return elements[index];
+ AbstractResumedStatement<?, ?, ?> get(final int index) {
+ return index >= elements.length ? null : elements[index];
}
@Override
- StatementMap put(final int index, final StatementContextBase<?, ?, ?> object) {
+ StatementMap put(final int index, final AbstractResumedStatement<?, ?, ?> obj) {
if (index < elements.length) {
checkArgument(elements[index] == null);
} else {
+ // FIXME: detect linear growth
elements = Arrays.copyOf(elements, index + 1);
}
- elements[index] = requireNonNull(object);
+ elements[index] = requireNonNull(obj);
+ size++;
return this;
}
@Override
- Collection<StatementContextBase<?, ?, ?>> values() {
- return new RegularAsCollection<>(elements);
- }
-
- @Override
- int size() {
- return countElements(elements);
- }
- }
-
- static int countElements(final Object[] elements) {
- // Optimized for non-sparse case
- int nulls = 0;
- for (Object e : elements) {
- if (e == null) {
- nulls++;
- }
- }
-
- return elements.length - nulls;
- }
-
- private static final class RegularAsCollection<T> extends AbstractCollection<T> {
- private final T[] elements;
-
- RegularAsCollection(final T[] elements) {
- this.elements = Preconditions.checkNotNull(elements);
+ public int size() {
+ return size;
}
@Override
- public void forEach(final Consumer<? super T> action) {
- for (T e : elements) {
- if (e != null) {
- action.accept(e);
- }
+ StatementMap ensureCapacity(final int expectedLimit) {
+ if (elements.length < expectedLimit) {
+ elements = Arrays.copyOf(elements, expectedLimit);
}
+ return this;
}
@Override
- public boolean isEmpty() {
- // This has a single-use and when it is instantiated, we know to have at least two items
- return false;
+ int capacity() {
+ return elements.length;
}
@Override
- public Iterator<T> iterator() {
- return new AbstractIterator<T>() {
+ public Iterator<AbstractResumedStatement<?, ?, ?>> iterator() {
+ return new AbstractIterator<>() {
private int nextOffset = 0;
@Override
- protected T computeNext() {
+ protected AbstractResumedStatement<?, ?, ?> computeNext() {
while (nextOffset < elements.length) {
- final T ret = elements[nextOffset++];
+ final AbstractResumedStatement<?, ?, ?> ret = elements[nextOffset++];
if (ret != null) {
return ret;
}
}
};
}
-
- @Override
- public int size() {
- return countElements(elements);
- }
}
private static final class Singleton extends StatementMap {
- private final StatementContextBase<?, ?, ?> object;
+ private final AbstractResumedStatement<?, ?, ?> object;
- Singleton(final StatementContextBase<?, ?, ?> object) {
+ Singleton(final AbstractResumedStatement<?, ?, ?> object) {
this.object = requireNonNull(object);
}
@Override
- StatementContextBase<?, ?, ?> get(final int index) {
+ AbstractResumedStatement<?, ?, ?> get(final int index) {
return index == 0 ? object : null;
}
@Override
- StatementMap put(final int index, final StatementContextBase<?, ?, ?> object) {
+ StatementMap put(final int index, final AbstractResumedStatement<?, ?, ?> obj) {
checkArgument(index != 0);
- return new Regular(this.object, index, object);
+ return new Regular(this.object, index, obj);
+ }
+
+ @Override
+ public int size() {
+ return 1;
}
@Override
- Collection<StatementContextBase<?, ?, ?>> values() {
- return ImmutableList.of(object);
+ StatementMap ensureCapacity(final int expectedLimit) {
+ return expectedLimit < 2 ? this : new Regular(expectedLimit, 0, object);
}
@Override
- int size() {
+ int capacity() {
return 1;
}
+
+ @Override
+ public Iterator<AbstractResumedStatement<?, ?, ?>> iterator() {
+ return Iterators.singletonIterator(object);
+ }
}
private static final StatementMap EMPTY = new Empty();
* @param index Element index, must be non-negative
* @return Requested element or null if there is no element at that index
*/
- abstract @Nullable StatementContextBase<?, ?, ?> get(int index);
+ abstract @Nullable AbstractResumedStatement<?, ?, ?> get(int index);
/**
* Add a statement at specified index.
*
* @param index Element index, must be non-negative
- * @param object Object to store
+ * @param obj Object to store
* @return New statement map
* @throws IllegalArgumentException if the index is already occupied
*/
- abstract @Nonnull StatementMap put(int index, @Nonnull StatementContextBase<?, ?, ?> object);
+ abstract @NonNull StatementMap put(int index, @NonNull AbstractResumedStatement<?, ?, ?> obj);
- /**
- * Return a read-only view of the elements in this map. Unlike other maps, this view does not detect concurrent
- * modification. Iteration is performed in order of increasing offset. In face of concurrent modification, number
- * of elements returned through iteration may not match the size reported via {@link Collection#size()}.
- *
- * @return Read-only view of available statements.
- */
- abstract @Nonnull Collection<StatementContextBase<?, ?, ?>> values();
+ abstract @NonNull StatementMap ensureCapacity(int expectedLimit);
- abstract int size();
+ abstract int capacity();
}
Code Review / yangtools.git / blobdiff