1 files changed, 131 insertions, 0 deletions
diff --git a/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/MappingSet.java b/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/MappingSet.java
new file mode 100644
index 00000000..9bf80a73
--- /dev/null
+++ b/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/MappingSet.java
@@ -0,0 +1,131 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.consistent.impl;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.Set;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import com.google.common.collect.Iterators;
+
+/**
+ * Set view backed by Set with element type {@code <BACK>} but returns
+ * element as {@code <OUT>} for convenience.
+ *
+ * @param <BACK> Backing {@link Set} element type.
+ *        MappingSet will follow this type's equality behavior.
+ * @param <OUT> external facing element type.
+ *        MappingSet will ignores equality defined by this type.
+ */
+class MappingSet<BACK, OUT> implements Set<OUT> {
+
+    private final Set<BACK> backedSet;
+    private final Function<OUT, BACK> toBack;
+    private final Function<BACK, OUT> toOut;
+
+    public MappingSet(Set<BACK> backedSet,
+                      Function<Set<BACK>, Set<BACK>> supplier,
+                      Function<OUT, BACK> toBack, Function<BACK, OUT> toOut) {
+        this.backedSet = supplier.apply(backedSet);
+        this.toBack = toBack;
+        this.toOut = toOut;
+    }
+
+    @Override
+    public int size() {
+        return backedSet.size();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return backedSet.isEmpty();
+    }
+
+    @Override
+    public boolean contains(Object o) {
+        return backedSet.contains(toBack.apply((OUT) o));
+    }
+
+    @Override
+    public Iterator<OUT> iterator() {
+        return Iterators.transform(backedSet.iterator(), toOut::apply);
+    }
+
+    @Override
+    public Object[] toArray() {
+        return backedSet.stream()
+                .map(toOut)
+                .toArray();
+    }
+
+    @Override
+    public <T> T[] toArray(T[] a) {
+        return backedSet.stream()
+                .map(toOut)
+                .toArray(size -> {
+                    if (size < a.length) {
+                        return (T[]) new Object[size];
+                    } else {
+                        Arrays.fill(a, null);
+                        return a;
+                    }
+                });
+    }
+
+    @Override
+    public boolean add(OUT e) {
+        return backedSet.add(toBack.apply(e));
+    }
+
+    @Override
+    public boolean remove(Object o) {
+        return backedSet.remove(toBack.apply((OUT) o));
+    }
+
+    @Override
+    public boolean containsAll(Collection<?> c) {
+        return c.stream()
+            .map(e -> toBack.apply((OUT) e))
+            .allMatch(backedSet::contains);
+    }
+
+    @Override
+    public boolean addAll(Collection<? extends OUT> c) {
+        return backedSet.addAll(c.stream().map(toBack).collect(Collectors.toList()));
+    }
+
+    @Override
+    public boolean retainAll(Collection<?> c) {
+        return backedSet.retainAll(c.stream()
+                .map(x -> toBack.apply((OUT) x))
+                .collect(Collectors.toList()));
+    }
+
+    @Override
+    public boolean removeAll(Collection<?> c) {
+        return backedSet.removeAll(c.stream()
+                .map(x -> toBack.apply((OUT) x))
+                .collect(Collectors.toList()));
+    }
+
+    @Override
+    public void clear() {
+        backedSet.clear();
+    }
+}