Java tutorial
/** * Copyright 2014 Yahoo! Inc. 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. * See accompanying LICENSE file. */ package com.yahoo.sql4d.sql4ddriver; import com.yahoo.sql4d.sql4ddriver.rowmapper.DruidBaseBean; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.logging.Level; import java.util.logging.Logger; import org.json.JSONArray; import org.json.JSONObject; /** * Simple utils. * @author srikalyan */ public class Util { public static final void newLine() { System.out.println(); } public static final void print(char c) { System.out.print(c); System.out.flush(); } public static final void print(String message) { System.out.print(message); System.out.flush(); } public static final void println(String message) { System.out.println(message); System.out.flush(); } public static final void printf(String format, Object... args) { System.out.printf(format, args); System.out.flush(); } public static final String repeat(String item, int n) { StringBuilder buff = new StringBuilder(); for (int i = 0; i < n; i++) { buff.append(item); } return buff.toString(); } public static void printTable(JSONArray jsonArray) { if (jsonArray.length() == 0) { return; } JSONObject sample = jsonArray.getJSONObject(0); if (sample.has("event")) {// GroupBy for (int i = 0; i < jsonArray.length(); i++) { JSONObject jsonItem = jsonArray.getJSONObject(i); JSONObject event = jsonItem.getJSONObject("event"); // Print headers. if (i == 0) { printf("%-10s |", "timestamp"); for (Object key : event.keySet()) { printf("%-10s |", key); } newLine(); } println(repeat("-", (event.keySet().size() + 1) * 10)); // Print data. printf("%-10s |", jsonItem.getString("timestamp")); for (Object key : event.keySet()) { printf("%-10s |", event.get(key.toString())); } newLine(); } } else if (sample.has("result")) {// Could be timeseries/topN if (sample.optJSONObject("result") != null) {// Timeseries JSONObject sampleResult = sample.optJSONObject("result"); // Print headers. printf("%-10s |", "timestamp"); for (Object key : sampleResult.keySet()) { printf("%-10s |", key); } newLine(); println(repeat("-", (sampleResult.keySet().size() + 1) * 10)); // Print data. for (int i = 0; i < jsonArray.length(); i++) { JSONObject jsonItem = jsonArray.getJSONObject(i); printf("%-10s |", jsonItem.getString("timestamp")); JSONObject result = jsonItem.getJSONObject("result"); for (Object key : result.keySet()) { printf("%-10s |", result.get(key.toString())); } newLine(); } } else if (sample.optJSONArray("result") != null) {// TopN // There should be only 1 item in here. JSONObject jsonItem = jsonArray.getJSONObject(0); JSONArray result = jsonItem.getJSONArray("result"); // Print headers. printf("%-10s |", "timestamp"); if (result.length() == 0) {// Nothing to be printed return; } for (Object key : result.getJSONObject(0).keySet()) { printf("%-10s |", key); } newLine(); println(repeat("-", (result.getJSONObject(0).keySet().size() + 1) * 10)); for (int j = 0; j < result.length(); j++) { printf("%-10s |", jsonItem.getString("timestamp")); JSONObject deepItem = result.getJSONObject(j); for (Object key : deepItem.keySet()) { printf("%-10s |", deepItem.get(key.toString())); } newLine(); } newLine(); } } } public static void printTable(List<String> baseFieldNames, Map<Object, List<Object>> baseAllRows) { for (String header : baseFieldNames) { printf("%-10s |", header); } newLine(); for (List<Object> row : baseAllRows.values()) { for (Object rowColValue : row) { printf("%-10s |", rowColValue); } newLine(); } } public static void printTable(List<String> baseFieldNames, List<List<Object>> baseAllRows) { for (String header : baseFieldNames) { printf("%-10s |", header); } newLine(); for (List<Object> row : baseAllRows) { for (Object rowColValue : row) { printf("%-10s |", rowColValue); } newLine(); } } public static <T extends DruidBaseBean> void printTable(List<T> baseAllRows) { if (baseAllRows == null || baseAllRows.isEmpty()) { return; } List<Method> setters = getAllSetters(baseAllRows.get(0).getClass()); for (Method setter : setters) { printf("%-10s |", setter.getName().substring(3)); } newLine(); List<Method> getters = getAllGetters(baseAllRows.get(0).getClass()); for (T row : baseAllRows) { for (Method getter : getters) { try { printf("%-10s |", getter.invoke(row)); } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) { Logger.getLogger(Util.class.getName()).log(Level.SEVERE, null, ex); } } newLine(); } } public static List<Method> getAllSetters(Class<?> clazz) { Method[] allMethods = clazz.getMethods(); List<Method> setters = new ArrayList<>(); for (Method method : allMethods) { if (method.getName().startsWith("set")) { setters.add(method); } } return setters; } public static List<Method> getAllGetters(Class<?> clazz) { Method[] allMethods = clazz.getMethods(); List<Method> getters = new ArrayList<>(); for (Method method : allMethods) { if (method.getName().startsWith("get") && !method.getName().equals("getClass")) { getters.add(method); } } return getters; } public static String getterMethodName(String key) { return "get" + capitalize(key); } public static String setterMethodName(String key) { return "set" + capitalize(key); } public static String capitalize(String word) { StringBuilder buff = new StringBuilder(word); if (word.charAt(0) != '_') { buff.setCharAt(0, Character.toUpperCase(word.charAt(0))); } for (int i = 1; i < buff.length(); i++) { if (buff.charAt(i - 1) == '_') { buff.setCharAt(i, Character.toUpperCase(word.charAt(i))); } } return buff.toString().replace("_", ""); } }