Move SpecProperties from drools-pdp to common

Change-Id: Ifa1785922b42f990d4d84c1410dd1d881b10647d
Issue-ID: POLICY-907
Signed-off-by: Jim Hahn <jrh3@att.com>

1 files changed, 117 insertions, 0 deletions

diff --git a/utils/src/main/java/org/onap/policy/common/utils/properties/SpecProperties.java b/utils/src/main/java/org/onap/policy/common/utils/properties/SpecProperties.java
new file mode 100644
index 00000000..0f416c3a
--- /dev/null
+++ b/utils/src/main/java/org/onap/policy/common/utils/properties/SpecProperties.java
@@ -0,0 +1,117 @@
+/*
+ * ============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.common.utils.properties;
+
+import java.util.Properties;
+
+/**
+ * Properties with an optional specialization (e.g., session name, controller name).
+ */
+public class SpecProperties extends Properties {
+    private static final long serialVersionUID = 1L;
+
+    /**
+     * The property prefix, ending with ".".
+     */
+    private final String prefix;
+
+    /**
+     * The specialized property prefix, ending with ".".
+     */
+    private final String specPrefix;
+
+    /**
+     * 
+     * @param prefix the property name prefix that appears before any specialization, may
+     *        be ""
+     * @param specialization the property name specialization (e.g., session name)
+     */
+    public SpecProperties(String prefix, String specialization) {
+        this.prefix = withTrailingDot(prefix);
+        this.specPrefix = withTrailingDot(this.prefix + specialization);
+    }
+
+    /**
+     * 
+     * @param prefix the property name prefix that appears before any specialization, may
+     *        be ""
+     * @param specialization the property name specialization (e.g., session name)
+     * @param props the default properties
+     */
+    public SpecProperties(String prefix, String specialization, Properties props) {
+        super(props);
+
+        this.prefix = withTrailingDot(prefix);
+        this.specPrefix = withTrailingDot(this.prefix + specialization);
+    }
+
+    /**
+     * Adds a trailing "." to a String, if it doesn't already have one.
+     * 
+     * @param text text to which the "." should be added
+     * @return the text, with a trailing "."
+     */
+    private static String withTrailingDot(String text) {
+        return text.isEmpty() || text.endsWith(".") ? text : text + ".";
+    }
+
+    /**
+     * Gets the property whose value has the given key, looking first for the specialized
+     * property name, and then for the generalized property name.
+     * 
+     * @param key property name, without the specialization
+     * @return the value from the property set, or {@code null} if the property set does
+     *         not contain the value
+     */
+    @Override
+    public String getProperty(String key) {
+        if (!key.startsWith(prefix)) {
+            return super.getProperty(key);
+        }
+
+        String suffix = key.substring(prefix.length());
+
+        String val = super.getProperty(specPrefix + suffix);
+        if (val != null) {
+            return val;
+        }
+
+        return super.getProperty(key);
+    }
+
+    protected String getPrefix() {
+        return prefix;
+    }
+
+    protected String getSpecPrefix() {
+        return specPrefix;
+    }
+
+    @Override
+    public final int hashCode() {
+        throw new UnsupportedOperationException("SpecProperties cannot be hashed");
+    }
+
+    @Override
+    public final boolean equals(Object obj) {
+        throw new UnsupportedOperationException("cannot compare SpecProperties");
+    }
+}