1 files changed, 142 insertions, 0 deletions
diff --git a/policy-core/src/main/java/org/onap/policy/drools/util/FeatureEnabledChecker.java b/policy-core/src/main/java/org/onap/policy/drools/util/FeatureEnabledChecker.java
new file mode 100644
index 00000000..800b6e89
--- /dev/null
+++ b/policy-core/src/main/java/org/onap/policy/drools/util/FeatureEnabledChecker.java
@@ -0,0 +1,142 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2018 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.drools.util;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Field;
+import java.util.Properties;
+import org.onap.policy.common.utils.properties.SpecPropertyConfiguration;
+import org.onap.policy.common.utils.properties.exception.PropertyException;
+
+/**
+ * Checks whether or not a feature is enabled. The name of the "enable" property
+ * is assumed to be of the form accepted by a {@link SpecPropertyConfiguration},
+ * which contains a substitution place-holder into which a "specializer" (e.g.,
+ * controller or session name) is substituted.
+ */
+public class FeatureEnabledChecker {
+
+    /**
+     * 
+     */
+    private FeatureEnabledChecker() {
+        super();
+    }
+
+    /**
+     * Determines if a feature is enabled for a particular specializer.
+     * 
+     * @param props properties from which to extract the "enabled" flag
+     * @param specializer specializer to be substituted into the property name
+     *        when extracting
+     * @param propName the name of the "enabled" property
+     * @return {@code true} if the feature is enabled, or {@code false} if it is
+     *         not enabled (or if the property doesn't exist)
+     * @throws IllegalArgumentException if the "enabled" property is not a
+     *         boolean value
+     */
+    public static boolean isFeatureEnabled(Properties props, String specializer, String propName) {
+
+        try {
+            return new Config(specializer, props, propName).isEnabled();
+
+        } catch (PropertyException e) {
+            throw new IllegalArgumentException("cannot check property " + propName, e);
+        }
+    }
+
+
+    /**
+     * Configuration used to extract the value.
+     */
+    private static class Config extends SpecPropertyConfiguration {
+
+        /**
+         * There is a bit of trickery here. This annotation is just a
+         * place-holder to get the superclass to invoke the
+         * {@link #setValue(java.lang.reflect.Field, Properties, Property)
+         * setValue()} method. When that's invoked, we'll substitute
+         * {@link #propOverride} instead of this annotation.
+         */
+        @Property(name = "feature-enabled-property-place-holder")
+        private boolean enabled;
+
+        /**
+         * Annotation that will actually be used to set the field.
+         */
+        private Property propOverride;
+
+        /**
+         * 
+         * @param specializer specializer to be substituted into the property
+         *        name when extracting
+         * @param props properties from which to extract the "enabled" flag
+         * @param propName the name of the "enabled" property
+         * @throws PropertyException if an error occurs
+         */
+        public Config(String specializer, Properties props, String propName) throws PropertyException {
+            super(specializer);
+
+            propOverride = new Property() {
+
+                @Override
+                public String name() {
+                    return propName;
+                }
+
+                @Override
+                public String defaultValue() {
+                    // feature is disabled by default
+                    return "false";
+                }
+
+                @Override
+                public String accept() {
+                    return "";
+                }
+
+                @Override
+                public Class<? extends Annotation> annotationType() {
+                    return Property.class;
+                }
+            };
+
+            setAllFields(props);
+        }
+
+        /**
+         * Substitutes {@link #propOverride} for "prop".
+         */
+        @Override
+        protected boolean setValue(Field field, Properties props, Property prop) throws PropertyException {
+            return super.setValue(field, props, propOverride);
+        }
+
+        /**
+         * 
+         * @return {@code true} if the feature is enabled, {@code false}
+         *         otherwise
+         */
+        public boolean isEnabled() {
+            return enabled;
+        }
+    };
+}