Add filters on policy objects

I just raised this review to shwo where I'm going with the
filters. They are not complete yet.

Issue-ID: POLICY-1095
Change-Id: I7b602a32bb67159b893f3b3cefea5d88038c4e5f
Signed-off-by: liamfallon <liam.fallon@est.tech>

1 files changed, 40 insertions, 0 deletions

diff --git a/models-base/src/main/java/org/onap/policy/models/base/PfObjectFiler.java b/models-base/src/main/java/org/onap/policy/models/base/PfObjectFiler.java
new file mode 100644
index 000000000..f1481bf3c
--- /dev/null
+++ b/models-base/src/main/java/org/onap/policy/models/base/PfObjectFiler.java
@@ -0,0 +1,40 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2019 Nordix 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.models.base;
+
+import java.util.List;
+
+/**
+ * Interface for filtering a list of concepts.
+ *
+ * @author Liam Fallon (liam.fallon@est.tech)
+ */
+@FunctionalInterface
+public interface PfObjectFiler<T> {
+    /**
+     * Filter an incoming list, removing items that do not match the filter.
+     *
+     * @param originalList the original list
+     * @return the filtered list
+     */
+    public List<T> filter(final List<T> originalList);
+
+}