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-rw-r--r--utils/src/main/java/org/onap/policy/common/utils/properties/PropertyObjectUtils.java243
1 files changed, 243 insertions, 0 deletions
diff --git a/utils/src/main/java/org/onap/policy/common/utils/properties/PropertyObjectUtils.java b/utils/src/main/java/org/onap/policy/common/utils/properties/PropertyObjectUtils.java
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+++ b/utils/src/main/java/org/onap/policy/common/utils/properties/PropertyObjectUtils.java
@@ -0,0 +1,243 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2019-2020 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.ArrayList;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Utilities for generating POJOs from Properties.
+ */
+public class PropertyObjectUtils {
+
+ public static final Logger logger = LoggerFactory.getLogger(PropertyObjectUtils.class);
+ private static final Pattern NAME_PAT = Pattern.compile("\\[(\\d{1,3})\\]$");
+
+ private PropertyObjectUtils() {
+ // do nothing
+ }
+
+ /**
+ * Converts a set of properties to a Map. Supports json-path style property names with
+ * "." separating components, where components may have an optional subscript.
+ *
+ * @param properties properties to be converted
+ * @param prefix properties whose names begin with this prefix are included. The
+ * prefix is stripped from the name before adding the value to the map
+ * @return a hierarchical map representing the properties
+ */
+ public static Map<String, Object> toObject(Properties properties, String prefix) {
+ String dottedPrefix = prefix + (prefix.isEmpty() || prefix.endsWith(".") ? "" : ".");
+ int pfxlen = dottedPrefix.length();
+
+ Map<String, Object> map = new LinkedHashMap<>();
+
+ for (String name : properties.stringPropertyNames()) {
+ if (name.startsWith(dottedPrefix)) {
+ String[] components = name.substring(pfxlen).split("[.]");
+ setProperty(map, components, properties.getProperty(name));
+ }
+ }
+
+ return map;
+ }
+
+ /**
+ * Sets a property within a hierarchical map.
+ *
+ * @param map map into which the value should be placed
+ * @param names property name components
+ * @param value value to be placed into the map
+ */
+ private static void setProperty(Map<String, Object> map, String[] names, String value) {
+ Map<String, Object> node = map;
+
+ final int lastComp = names.length - 1;
+
+ // process all but the final component
+ for (int comp = 0; comp < lastComp; ++comp) {
+ node = getNode(node, names[comp]);
+ }
+
+ // process the final component
+ String name = names[lastComp];
+ Matcher matcher = NAME_PAT.matcher(name);
+
+ if (!matcher.find()) {
+ // no subscript
+ node.put(name, value);
+ return;
+ }
+
+ // subscripted
+ List<Object> array = getArray(node, name.substring(0, matcher.start()));
+ int index = Integer.parseInt(matcher.group(1));
+ expand(array, index);
+ array.set(index, value);
+ }
+
+ /**
+ * Gets a node.
+ *
+ * @param map map from which to get the object
+ * @param name name of the element to get from the map, with an optional subscript
+ * @return a Map
+ */
+ @SuppressWarnings("unchecked")
+ private static Map<String, Object> getNode(Map<String, Object> map, String name) {
+ Matcher matcher = NAME_PAT.matcher(name);
+
+ if (!matcher.find()) {
+ // no subscript
+ return getObject(map, name);
+ }
+
+ // subscripted
+ List<Object> array = getArray(map, name.substring(0, matcher.start()));
+ int index = Integer.parseInt(matcher.group(1));
+ expand(array, index);
+
+ Object item = array.get(index);
+ if (item instanceof Map) {
+ return (Map<String, Object>) item;
+
+ } else {
+ LinkedHashMap<String, Object> result = new LinkedHashMap<>();
+ array.set(index, result);
+ return result;
+ }
+ }
+
+ /**
+ * Ensures that an array's size is large enough to hold the specified element.
+ *
+ * @param array array to be expanded
+ * @param index index of the desired element
+ */
+ private static void expand(List<Object> array, int index) {
+ while (array.size() <= index) {
+ array.add(null);
+ }
+ }
+
+ /**
+ * Gets an object (i.e., Map) from a map. If the particular element is not a Map, then
+ * it is replaced with an empty Map.
+ *
+ * @param map map from which to get the object
+ * @param name name of the element to get from the map, without any subscript
+ * @return a Map
+ */
+ private static Map<String, Object> getObject(Map<String, Object> map, String name) {
+ @SuppressWarnings("unchecked")
+ Map<String, Object> result = (Map<String, Object>) map.compute(name, (key, value) -> {
+ if (value instanceof Map) {
+ return value;
+ } else {
+ return new LinkedHashMap<>();
+ }
+ });
+
+ return result;
+ }
+
+ /**
+ * Gets an array from a map. If the particular element is not an array, then it is
+ * replaced with an empty array.
+ *
+ * @param map map from which to get the array
+ * @param name name of the element to get from the map, without any subscript
+ * @return an array
+ */
+ private static List<Object> getArray(Map<String, Object> map, String name) {
+ @SuppressWarnings("unchecked")
+ List<Object> result = (List<Object>) map.compute(name, (key, value) -> {
+ if (value instanceof List) {
+ return value;
+ } else {
+ return new ArrayList<>();
+ }
+ });
+
+ return result;
+ }
+
+ /**
+ * Compresses lists contained within a generic object, removing all {@code null}
+ * items.
+ *
+ * @param object object to be compressed
+ * @return the original object, modified in place
+ */
+ public static Object compressLists(Object object) {
+ if (object instanceof Map) {
+ @SuppressWarnings("unchecked")
+ Map<String, Object> asMap = (Map<String, Object>) object;
+ compressMapValues(asMap);
+
+ } else if (object instanceof List) {
+ @SuppressWarnings("unchecked")
+ List<Object> asList = (List<Object>) object;
+ compressListItems(asList);
+ }
+
+ // else: ignore anything else
+
+ return object;
+ }
+
+ /**
+ * Walks a hierarchical map and removes {@code null} items found in any Lists.
+ *
+ * @param map map whose lists are to be compressed
+ */
+ private static void compressMapValues(Map<String, Object> map) {
+ for (Object value : map.values()) {
+ compressLists(value);
+ }
+ }
+
+ /**
+ * Removes {@code null} items from the list. In addition, it walks the items within
+ * the list, compressing them, as well.
+ *
+ * @param list the list to be compressed
+ */
+ private static void compressListItems(List<Object> list) {
+ Iterator<Object> iter = list.iterator();
+ while (iter.hasNext()) {
+ Object item = iter.next();
+ if (item == null) {
+ // null item - remove it
+ iter.remove();
+
+ } else {
+ compressLists(item);
+ }
+ }
+ }
+}