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Diffstat (limited to 'appc-core/appc-common-bundle/java/org/onap/appc/util/JsonUtil.java')
| -rw-r--r-- | appc-core/appc-common-bundle/java/org/onap/appc/util/JsonUtil.java | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/appc-core/appc-common-bundle/java/org/onap/appc/util/JsonUtil.java b/appc-core/appc-common-bundle/java/org/onap/appc/util/JsonUtil.java new file mode 100644 index 000000000..14784595c --- /dev/null +++ b/appc-core/appc-common-bundle/java/org/onap/appc/util/JsonUtil.java @@ -0,0 +1,126 @@ +/*- + * ============LICENSE_START======================================================= + * ONAP : APPC + * ================================================================================ + * Copyright (C) 2017-2018 AT&T Intellectual Property. All rights reserved. + * ================================================================================ + * Copyright (C) 2017 Amdocs + * ============================================================================= + * 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.appc.util; + +import java.io.FileNotFoundException; +import java.io.IOException; +import java.io.InputStream; +import java.util.Map; +import com.fasterxml.jackson.annotation.JsonInclude; +import com.fasterxml.jackson.core.JsonParser; +import com.fasterxml.jackson.databind.DeserializationFeature; +import com.fasterxml.jackson.databind.ObjectMapper; +import com.fasterxml.jackson.databind.SerializationFeature; + +public class JsonUtil { + + static ObjectMapper MAPPER = null; + static { + MAPPER = new ObjectMapper(); + MAPPER.enable(SerializationFeature.INDENT_OUTPUT); + MAPPER.configure(JsonParser.Feature.ALLOW_COMMENTS, true); + MAPPER.setSerializationInclusion(JsonInclude.Include.NON_NULL); + MAPPER.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES); // allow translation even + // if extra attrs exist + // in the json + MAPPER.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false); + // Uncomment below when Jackson is upgraded to version 2.7 or above + // MAPPER.setPropertyNamingStrategy(PropertyNamingStrategy.KEBAB_CASE); + } + + /** + * @param valueAsString a valid json Map represented as String + * @return a flat map that each entry key derived from hierarchy path in the json object and + * flatted to a dotted separated string. e.g. + * "{\"A\":\"A-value\",\"B\":{\"C\":\"B.C-value\",\"D\":\"B.D-value\"}}"; will be + * represented as {A=A-value, B.C=B.C-value, B.D=B.D-value} when it required that the + * input will not be flatted the json string should be formatted as below example: e.g. + * "{\"A\":\"A-value\",\"B\":\"{\\\"C\\\":\\\"C-value\\\",\\\"D\\\":\\\"D-value\\\"}\"}" + * will be represented as {A=A-value, B={"C":"C-value","D":"D-value"}} + * @throws IOException when the object is not valid json Map + */ + public static Map<String, String> convertJsonStringToFlatMap(String valueAsString) + throws IOException { + Map readValueMap = MAPPER.readValue(valueAsString, Map.class); + return org.onap.appc.util.ObjectMapper.map(readValueMap); + } + + /** + * 0 is the getStackTrace method 1 is the current method 2 is the parent method, 3 is the + * grandparent method or the parent class in this case. + */ + private static final int PARENT_CLASS_INDEX = 3; + + + /** + * @see #readInputJson(String, Class, Class) + */ + public static <T> T readInputJson(String location, Class<T> returnClass) throws IOException { + return readInputJson(location, returnClass, getCallingClass(PARENT_CLASS_INDEX)); + } + + /** + * @param location The location or name of the file we are trying to read e.g. JsonBody.json + * @param returnClass The class *this* Json is suppose to represent. + * @param locationClass The starting point for json lookup. the value specified by location is + * relative to this class. + * @return The object being returned + * @throws IOException Can't find the specified json file at Location. + */ + public static <T> T readInputJson(String location, Class<T> returnClass, Class<?> locationClass) + throws IOException { + try (InputStream is = locationClass.getResourceAsStream(location)) { + validateInput(is, location); + return MAPPER.readValue(is, returnClass); + } + } + + /** + * Note that this method is sensitive to the depth of the call stack. For example if a public + * method calls a private method, that calls this method likely the desired classIndex value is + * 4 rather than 3. However, it's convenient to reduce the input required by callers of this + * class. + * + * @param classIndex How far up the stack trace to find the class we want. + * @return The class that called one of the public methods of this class. + */ + private static Class<?> getCallingClass(int classIndex) { + String className = Thread.currentThread().getStackTrace()[classIndex].getClassName(); + try { + return Class.forName(className); + } catch (ClassNotFoundException e) { + // Theoretically impossible. + throw new IllegalStateException( + "Could not do class lookup for class in our stack trace?!?"); + } + } + + private static void validateInput(InputStream is, String location) + throws FileNotFoundException { + if (is == null) { + throw new FileNotFoundException(String.format("Could not find file at '%s'", location)); + } + } + +} |