Pull out inner-classes from Criteria to be independent classes

Make constructors of sub-types of Criterion package private for
limiting instantiation only from static factory methods in Criteria

Change-Id: I1fb1e9d003288a778a49e758549a92b66bf3cfdf
diff --git a/core/api/src/main/java/org/onosproject/net/flow/criteria/IPv6ExthdrFlagsCriterion.java b/core/api/src/main/java/org/onosproject/net/flow/criteria/IPv6ExthdrFlagsCriterion.java
new file mode 100644
index 0000000..c9d7a3ce
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/flow/criteria/IPv6ExthdrFlagsCriterion.java
@@ -0,0 +1,78 @@
+/*
+ * 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.net.flow.criteria;
+
+import java.util.Objects;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+/**
+ * Implementation of IPv6 Extension Header pseudo-field criterion
+ * (16 bits). Those are defined in Criterion.IPv6ExthdrFlags.
+ */
+public final class IPv6ExthdrFlagsCriterion implements Criterion {
+    private static final int MASK = 0xffff;
+    private final int exthdrFlags;          // IPv6 Exthdr flags: 16 bits
+
+    /**
+     * Constructor.
+     *
+     * @param exthdrFlags the IPv6 Extension Header pseudo-field flags
+     * to match (16 bits). Those are defined in Criterion.IPv6ExthdrFlags
+     */
+    IPv6ExthdrFlagsCriterion(int exthdrFlags) {
+        this.exthdrFlags = exthdrFlags & MASK;
+    }
+
+    @Override
+    public Type type() {
+        return Type.IPV6_EXTHDR;
+    }
+
+    /**
+     * Gets the IPv6 Extension Header pseudo-field flags to match.
+     *
+     * @return the IPv6 Extension Header pseudo-field flags to match
+     * (16 bits). Those are defined in Criterion.IPv6ExthdrFlags
+     */
+    public int exthdrFlags() {
+        return exthdrFlags;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(type().toString())
+            .add("exthdrFlags", Long.toHexString(exthdrFlags)).toString();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(type(), exthdrFlags);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof IPv6ExthdrFlagsCriterion) {
+            IPv6ExthdrFlagsCriterion that = (IPv6ExthdrFlagsCriterion) obj;
+            return Objects.equals(exthdrFlags, that.exthdrFlags) &&
+                    Objects.equals(this.type(), that.type());
+        }
+        return false;
+    }
+}