Java tutorial
/** * SusiTransfer * Copyright 14.07.2016 by Michael Peter Christen, @0rb1t3r * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program in the file lgpl21.txt * If not, see <http://www.gnu.org/licenses/>. */ package ai.susi.mind; import java.util.Iterator; import java.util.LinkedHashMap; import java.util.Map; import java.util.Set; import org.json.JSONArray; import org.json.JSONObject; import com.google.common.util.concurrent.AtomicDouble; /** * Transfer is the ability to perceive a given thought in a different representation * in such a way that it applies on a skill or a skill set. */ public class SusiTransfer { private LinkedHashMap<String, String> selectionMapping; /** * Create a new transfer. The mapping must be given in the same way as SQL column selection * statements. The selection of sub-objects of json object can be done using dot-notion. * Arrays can be accessed using brackets '[' and ']'. An example is: * mapping = "location.lon AS longitude, location.lat AS latitude" * or * mapping = "names[0] AS firstname" * As a reference, the mappingExpression shall be superset of a list of * https://mariadb.com/kb/en/mariadb/select/#select-expressions * @param mapping */ public SusiTransfer(String mappingExpression) { this.selectionMapping = parse(mappingExpression); } /** * get the set of transfer keys * @return */ public Set<String> keys() { return this.selectionMapping.keySet(); } /** * transfer mappings can be used to extract specific information from a json object to * create a new json object. In the context of Susi this is applied on choices from thought data * @param choice one 'row' of a SusiThought data array * @return a choice where the elements of the given choice are extracted according to the given mapping */ public JSONObject extract(JSONObject choice) { if (this.selectionMapping == null) return choice; JSONObject json = new JSONObject(true); for (Map.Entry<String, String> c : selectionMapping.entrySet()) { String key = c.getKey(); int p = key.indexOf('.'); if (p > 0) { // sub-element String k0 = key.substring(0, p); String k1 = key.substring(p + 1); if (choice.has(k0)) { if (k1.equals("length") || k1.equals("size()")) { Object a = choice.get(k0); if (a instanceof String[]) { json.put(c.getValue(), ((String[]) a).length); } else if (a instanceof JSONArray) { json.put(c.getValue(), ((JSONArray) a).length()); } } else { JSONObject o = choice.getJSONObject(k0); if (o.has(k1)) json.put(c.getValue(), o.get(k1)); } } } else if ((p = key.indexOf('[')) > 0) { // array int q = key.indexOf("]", p); if (q > 0) { String k0 = key.substring(0, p); int i = Integer.parseInt(key.substring(p + 1, q)); if (choice.has(k0)) { JSONArray a = choice.getJSONArray(k0); if (i < a.length()) json.put(c.getValue(), a.get(i)); } } } else { // flat if (choice.has(key)) json.put(c.getValue(), choice.get(key)); } } return json; } /** * A conclusion from choices is done by the application of a function on the choice set. * This may be done by i.e. counting the number of choices or extracting a maximum element. * @param choices the given set of json objects from the data object of a SusiThought * @returnan array of json objects which are the extraction of given choices according to the given mapping */ public JSONArray conclude(JSONArray choices) { JSONArray a = new JSONArray(); if (this.selectionMapping != null && this.selectionMapping.size() == 1) { // test if this has an aggregation key: AVG, COUNT, MAX, MIN, SUM final String aggregator = this.selectionMapping.keySet().iterator().next(); final String aggregator_as = this.selectionMapping.get(aggregator); if (aggregator.startsWith("COUNT(") && aggregator.endsWith(")")) { // TODO: there should be a special pattern for this to make it more efficient return a.put(new JSONObject().put(aggregator_as, choices.length())); } if (aggregator.startsWith("MAX(") && aggregator.endsWith(")")) { final AtomicDouble max = new AtomicDouble(Double.MIN_VALUE); String c = aggregator.substring(4, aggregator.length() - 1); choices.forEach(json -> max.set(Math.max(max.get(), ((JSONObject) json).getDouble(c)))); return a.put(new JSONObject().put(aggregator_as, max.get())); } if (aggregator.startsWith("MIN(") && aggregator.endsWith(")")) { final AtomicDouble min = new AtomicDouble(Double.MAX_VALUE); String c = aggregator.substring(4, aggregator.length() - 1); choices.forEach(json -> min.set(Math.min(min.get(), ((JSONObject) json).getDouble(c)))); return a.put(new JSONObject().put(aggregator_as, min.get())); } if (aggregator.startsWith("SUM(") && aggregator.endsWith(")")) { final AtomicDouble sum = new AtomicDouble(0.0d); String c = aggregator.substring(4, aggregator.length() - 1); choices.forEach(json -> sum.addAndGet(((JSONObject) json).getDouble(c))); return a.put(new JSONObject().put(aggregator_as, sum.get())); } if (aggregator.startsWith("AVG(") && aggregator.endsWith(")")) { final AtomicDouble sum = new AtomicDouble(0.0d); String c = aggregator.substring(4, aggregator.length() - 1); choices.forEach(json -> sum.addAndGet(((JSONObject) json).getDouble(c))); return a.put(new JSONObject().put(aggregator_as, sum.get() / choices.length())); } } if (this.selectionMapping != null && this.selectionMapping.size() == 2) { Iterator<String> ci = this.selectionMapping.keySet().iterator(); String aggregator = ci.next(); String column = ci.next(); if (column.indexOf('(') >= 0) { String s = aggregator; aggregator = column; column = s; } final String aggregator_as = this.selectionMapping.get(aggregator); final String column_as = this.selectionMapping.get(column); final String column_final = column; if (aggregator.startsWith("PERCENT(") && aggregator.endsWith(")")) { final AtomicDouble sum = new AtomicDouble(0.0d); String c = aggregator.substring(8, aggregator.length() - 1); choices.forEach(json -> sum.addAndGet(((JSONObject) json).getDouble(c))); choices.forEach(json -> a.put( new JSONObject().put(aggregator_as, 100.0d * ((JSONObject) json).getDouble(c) / sum.get()) .put(column_as, ((JSONObject) json).get(column_final)))); return a; } } // this.selectionMapping == null -> extract everything for (Object json : choices) { JSONObject extraction = this.extract((JSONObject) json); if (extraction.length() > 0) a.put(extraction); } return a; } private static LinkedHashMap<String, String> parse(String mapping) { LinkedHashMap<String, String> columns; String[] column_list = mapping.trim().split(","); if (column_list.length == 1 && column_list[0].equals("*")) { columns = null; } else { columns = new LinkedHashMap<>(); for (String column : column_list) { String c = column.trim(); int p = c.indexOf(" AS "); if (p < 0) { c = trimQuotes(c); columns.put(c, c); } else { columns.put(trimQuotes(c.substring(0, p).trim()), trimQuotes(c.substring(p + 4).trim())); } } } return columns; } private static String trimQuotes(String s) { if (s.length() == 0) return s; if (s.charAt(0) == '\'' || s.charAt(0) == '\"') s = s.substring(1); if (s.charAt(s.length() - 1) == '\'' || s.charAt(s.length() - 1) == '\"') s = s.substring(0, s.length() - 1); return s; } public String toString() { return this.selectionMapping == null ? "NULL" : this.selectionMapping.toString(); } }