Add EntrySet/KeySet spliterators

Spliterators do not allow modification of underlying map, hence
we can always instantiate an immutable iterator and flag appropriate
characteristics.

This is an initial cut, which is not perfect: we still should create
dedicated spliterators, which do not instantie entries nor perform
lookahead and have optimized trySplit().

Change-Id: Iad1a8f4b30d5a996484b21c9be589bf80ee7d584
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

diff --git a/third-party/triemap/src/main/java/org/opendaylight/yangtools/triemap/AbstractEntrySet.java b/third-party/triemap/src/main/java/org/opendaylight/yangtools/triemap/AbstractEntrySet.java
index 4eb05ba1ab13f44f121e2a30502a0bf2d601d251..6ccee5a33f6c047c5d2273db96dc7a315360b84d 100644 (file)
--- a/third-party/triemap/src/main/java/org/opendaylight/yangtools/triemap/AbstractEntrySet.java
+++ b/third-party/triemap/src/main/java/org/opendaylight/yangtools/triemap/AbstractEntrySet.java
@@ -19,6 +19,8 @@ import static java.util.Objects.requireNonNull;
 
 import java.util.AbstractSet;
 import java.util.Map.Entry;
+import java.util.Spliterator;
+import java.util.Spliterators;
 
 /**
  * Abstract base class for implementing {@link TrieMap} entry sets.
@@ -60,4 +62,12 @@ abstract class AbstractEntrySet<K, V> extends AbstractSet<Entry<K, V>> {
     public final int size() {
         return map.size();
     }
+
+    @Override
+    public final Spliterator<Entry<K, V>> spliterator() {
+        // TODO: this is backed by an Iterator, we should be able to do better
+        return Spliterators.spliterator(map.immutableIterator(), Long.MAX_VALUE,
+            // XXX: Distinct as far as associated Equivalence allows
+            Spliterator.DISTINCT | Spliterator.IMMUTABLE | Spliterator.NONNULL);
+    }
 }

diff --git a/third-party/triemap/src/main/java/org/opendaylight/yangtools/triemap/AbstractKeySet.java b/third-party/triemap/src/main/java/org/opendaylight/yangtools/triemap/AbstractKeySet.java
index 869a15dbd38a1ac844606bfd9d05030d7b68f597..e04dc46c88b77429ba2f5e3ea9b7ab0b43dbf76b 100644 (file)
--- a/third-party/triemap/src/main/java/org/opendaylight/yangtools/triemap/AbstractKeySet.java
+++ b/third-party/triemap/src/main/java/org/opendaylight/yangtools/triemap/AbstractKeySet.java
@@ -17,8 +17,12 @@ package org.opendaylight.yangtools.triemap;
 
 import static java.util.Objects.requireNonNull;
 
+import com.google.common.collect.Iterators;
 import java.util.AbstractSet;
 import java.util.Collection;
+import java.util.Map.Entry;
+import java.util.Spliterator;
+import java.util.Spliterators;
 
 /**
  * Abstract base class for key set views of a TrieMap.
@@ -65,4 +69,12 @@ abstract class AbstractKeySet<K> extends AbstractSet<K> {
     public final int size() {
         return map.size();
     }
+
+    @Override
+    public final Spliterator<K> spliterator() {
+        // TODO: this is backed by an Iterator, we should be able to do better
+        return Spliterators.spliterator(Iterators.transform(map().immutableIterator(), Entry::getKey), Long.MAX_VALUE,
+            // XXX: Distinct as far as associated Equivalence allows
+            Spliterator.DISTINCT | Spliterator.IMMUTABLE | Spliterator.NONNULL);
+    }
 }