1 files changed, 129 insertions, 0 deletions
diff --git a/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/Match.java b/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/Match.java
new file mode 100644
index 00000000..5f707d62
--- /dev/null
+++ b/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/Match.java
@@ -0,0 +1,129 @@
+/*
+ * 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 static com.google.common.base.MoreObjects.toStringHelper;
+
+import java.util.Arrays;
+import java.util.Objects;
+import java.util.function.Function;
+
+/**
+ * Utility class for checking matching values.
+ *
+ * @param <T> type of value
+ */
+public final class Match<T> {
+
+    private final boolean matchAny;
+    private final T value;
+
+    /**
+     * Returns a Match that matches any value.
+     * @param <T> match type
+     * @return new instance
+     */
+    public static <T> Match<T> any() {
+        return new Match<>();
+    }
+
+    /**
+     * Returns a Match that matches null values.
+     * @param <T> match type
+     * @return new instance
+     */
+    public static <T> Match<T> ifNull() {
+        return ifValue(null);
+    }
+
+    /**
+     * Returns a Match that matches only specified value.
+     * @param value value to match
+     * @param <T> match type
+     * @return new instance
+     */
+    public static <T> Match<T> ifValue(T value) {
+        return new Match<>(value);
+    }
+
+    private Match() {
+        matchAny = true;
+        value = null;
+    }
+
+    private Match(T value) {
+        matchAny = false;
+        this.value = value;
+    }
+
+    /**
+     * Maps this instance to a Match of another type.
+     * @param mapper transformation function
+     * @param <V> new match type
+     * @return new instance
+     */
+    public <V> Match<V> map(Function<T, V> mapper) {
+        if (matchAny) {
+            return any();
+        } else if (value == null) {
+            return ifNull();
+        } else {
+            return ifValue(mapper.apply(value));
+        }
+    }
+
+    /**
+     * Checks if this instance matches specified value.
+     * @param other other value
+     * @return true if matches; false otherwise
+     */
+    public boolean matches(T other) {
+        if (matchAny) {
+            return true;
+        } else if (other == null) {
+            return value == null;
+        } else {
+            if (value instanceof byte[]) {
+                return Arrays.equals((byte[]) value, (byte[]) other);
+            }
+            return Objects.equals(value, other);
+        }
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(matchAny, value);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public boolean equals(Object other) {
+        if (!(other instanceof Match)) {
+            return false;
+        }
+        Match<T> that = (Match<T>) other;
+        return Objects.equals(this.matchAny, that.matchAny) &&
+               Objects.equals(this.value, that.value);
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("matchAny", matchAny)
+                .add("value", value)
+                .toString();
+    }
+}