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69 lines
2.3 KiB
Java
69 lines
2.3 KiB
Java
package com.darylbeattie.movies.util;
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import java.io.IOException;
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import java.lang.annotation.Annotation;
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import java.lang.reflect.Field;
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import java.lang.reflect.ParameterizedType;
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import java.util.List;
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import org.json.JSONArray;
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import org.json.JSONObject;
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public class ObjectMapper {
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/**
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* This takes a JSON string and creates (and populates) an object of the given class
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* with the data from that JSON string. It mimics the method signature of the jackson
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* JSON API, so that we don't have to import the jackson library into this application.
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*
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* @param jsonString The JSON string to parse.
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* @param objClass The class of object we want to create.
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* @return The instantiation of that class, populated with data from the JSON object.
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* @throws IOException If there was any kind of issue.
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*/
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public <T> T readValue(String jsonString, Class<T> objClass) throws IOException {
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try {
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return readValue(new JSONObject(jsonString), objClass);
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}
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catch (IOException ioe) {
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throw ioe;
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}
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catch (Exception e) {
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e.printStackTrace();
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throw new IOException(e);
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}
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}
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@SuppressWarnings("unchecked")
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public <T, R> T readValue(JSONObject json, Class<T> objClass) throws IOException {
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try {
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//TODO Iterate through json object values and call the JsonAnySetter method on the unknown ones.
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T obj = objClass.newInstance();
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for (Field f : objClass.getFields()) {
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Annotation a = f.getAnnotation(JsonProperty.class);
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if (List.class.equals(f.getType()) && (json.optJSONArray(((JsonProperty) a).value()) != null)) { // It's a list.
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JSONArray jsonArray = json.optJSONArray(((JsonProperty) a).value());
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ParameterizedType listType = (ParameterizedType) f.getGenericType();
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Class<?> subObj = (Class<?>) listType.getActualTypeArguments()[0];
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List<R> subObjList = ((Class<List<R>>) f.getType()).newInstance();
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for (int i = 0; i < jsonArray.length(); i++) {
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subObjList.add((R) readValue(jsonArray.getJSONObject(i), subObj));
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}
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f.set(obj, subObjList);
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}
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else if (a != null) {
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f.set(obj, json.opt(((JsonProperty) a).value()));
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}
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}
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return obj;
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}
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catch (IOException ioe) {
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throw ioe;
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}
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catch (Exception e) {
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e.printStackTrace();
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throw new IOException(e);
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}
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}
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} |