Add Optional match fields support to PI subsystem

Change-Id: Ic458f59cab98340e40c04a0ad060d3c725ac5dbb
diff --git a/core/api/src/main/java/org/onosproject/net/flow/criteria/PiCriterion.java b/core/api/src/main/java/org/onosproject/net/flow/criteria/PiCriterion.java
index 17d1270..3970e76 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/criteria/PiCriterion.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/criteria/PiCriterion.java
@@ -23,6 +23,7 @@
 import org.onosproject.net.pi.runtime.PiExactFieldMatch;
 import org.onosproject.net.pi.runtime.PiFieldMatch;
 import org.onosproject.net.pi.runtime.PiLpmFieldMatch;
+import org.onosproject.net.pi.runtime.PiOptionalFieldMatch;
 import org.onosproject.net.pi.runtime.PiRangeFieldMatch;
 import org.onosproject.net.pi.runtime.PiTernaryFieldMatch;
 
@@ -350,6 +351,54 @@
         }
 
         /**
+         * Adds an optional field match for the given fieldId and value.
+         *
+         * @param fieldId protocol-independent header field Id
+         * @param value   optional match value
+         * @return this
+         */
+        public Builder matchOptional(PiMatchFieldId fieldId, short value) {
+            fieldMatchMapBuilder.put(fieldId, new PiOptionalFieldMatch(fieldId, copyFrom(value)));
+            return this;
+        }
+
+        /**
+         * Adds an optional field match for the given fieldId and value.
+         *
+         * @param fieldId protocol-independent header field Id
+         * @param value   optional match value
+         * @return this
+         */
+        public Builder matchOptional(PiMatchFieldId fieldId, int value) {
+            fieldMatchMapBuilder.put(fieldId, new PiOptionalFieldMatch(fieldId, copyFrom(value)));
+            return this;
+        }
+
+        /**
+         * Adds an optional field match for the given fieldId and value.
+         *
+         * @param fieldId protocol-independent header field Id
+         * @param value   optional match value
+         * @return this
+         */
+        public Builder matchOptional(PiMatchFieldId fieldId, long value) {
+            fieldMatchMapBuilder.put(fieldId, new PiOptionalFieldMatch(fieldId, copyFrom(value)));
+            return this;
+        }
+
+        /**
+         * Adds an optional field match for the given fieldId and value.
+         *
+         * @param fieldId protocol-independent header field Id
+         * @param value   optional match value
+         * @return this
+         */
+        public Builder matchOptional(PiMatchFieldId fieldId, byte[] value) {
+            fieldMatchMapBuilder.put(fieldId, new PiOptionalFieldMatch(fieldId, copyFrom(value)));
+            return this;
+        }
+
+        /**
          * Builds a PiCriterion.
          *
          * @return PiCriterion
diff --git a/core/api/src/main/java/org/onosproject/net/pi/model/PiMatchType.java b/core/api/src/main/java/org/onosproject/net/pi/model/PiMatchType.java
index f4fce3e..a0cb161 100644
--- a/core/api/src/main/java/org/onosproject/net/pi/model/PiMatchType.java
+++ b/core/api/src/main/java/org/onosproject/net/pi/model/PiMatchType.java
@@ -42,5 +42,10 @@
     /**
      * Range match type.
      */
-    RANGE
+    RANGE,
+
+    /**
+     * Optional match type.
+     */
+    OPTIONAL
 }
diff --git a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiOptionalFieldMatch.java b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiOptionalFieldMatch.java
new file mode 100644
index 0000000..cb34981
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiOptionalFieldMatch.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2020-present Open Networking Foundation
+ *
+ * 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.net.pi.runtime;
+
+import com.google.common.annotations.Beta;
+import com.google.common.base.Objects;
+import org.onlab.util.ImmutableByteSequence;
+import org.onosproject.net.pi.model.PiMatchFieldId;
+import org.onosproject.net.pi.model.PiMatchType;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Instance of an optional field match in a protocol-independent pipeline.
+ * The optional match field behaves like an exact match if specified, otherwise
+ * it is logically equivalent to a wildcard match.
+ */
+@Beta
+public final class PiOptionalFieldMatch extends PiFieldMatch {
+
+    private final ImmutableByteSequence value;
+
+    /**
+     * Creates an optional field match.
+     *
+     * @param fieldId field identifier
+     * @param value   value
+     */
+    public PiOptionalFieldMatch(PiMatchFieldId fieldId, ImmutableByteSequence value) {
+        super(fieldId);
+        this.value = checkNotNull(value);
+        checkArgument(value.size() > 0, "Value can't have size 0");
+    }
+
+    @Override
+    public PiMatchType type() {
+        return PiMatchType.OPTIONAL;
+    }
+
+    /**
+     * Returns the byte sequence value to be matched.
+     *
+     * @return an immutable byte sequence
+     */
+    public ImmutableByteSequence value() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        PiOptionalFieldMatch that = (PiOptionalFieldMatch) o;
+        return Objects.equal(this.fieldId(), that.fieldId()) &&
+                Objects.equal(value, that.value);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(this.fieldId(), value);
+    }
+
+    @Override
+    public String toString() {
+        return this.fieldId().toString() + "=" + value.toString();
+    }
+}