Java tutorial
// // Copyright 2010 Cinch Logic Pty Ltd. // // http://www.chililog.com // // 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. // package org.chililog.server.data; import java.text.SimpleDateFormat; import java.util.Date; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.commons.lang.StringUtils; import org.bson.BSONCallback; import com.mongodb.util.JSONCallback; /** * <p> * Parser for JSON objects and converts them into mongoDB DBObjects. * </p> * <p> * Supports all types described at www.json.org, except for numbers with "e" or "E" in them. * </p> * <p> * Modified from https://github.com/mongodb/mongo-java-driver/blob/master/src/main/com/mongodb/util/JSON.java. * </p> * <p> * Modified to support: * <ul> * <li>Long - Number >10 digits or string of digits with L at the end "123412341234L"</li> * <li>Date - Format is as per specified on the constructor.</li> * </p> */ public class MongoJsonParser { private Pattern _datePattern = null; private Pattern _longNumberPattern = null; private SimpleDateFormat _dateFormat = null; String s; int pos = 0; BSONCallback _callback; /** * Create a new parser without parsing strings for dates and time. * * @param s * String to parse */ public MongoJsonParser(String s) { this(s, null); } /** * Create a new parser and parse string values for dates and times as per the specified formats. * * @param s * String to parse * @param datePattern * Regular expression to use to test if a string is a date. Group #1 in the pattern is used. If null, no * date checking is performed. * @param dateFormat * {@link SimpleDateFormat} pattern to use to parse the date. If null, no date parsing is performed. * @param longNumberPattern * Regular expression to use to test if a string is a long number. Group #1 in the pattern is used. If * null, no long number matching is performed. */ public MongoJsonParser(String s, Pattern datePattern, String dateFormat, Pattern longNumberPattern) { this(s, null); _datePattern = datePattern; _dateFormat = StringUtils.isBlank(dateFormat) ? null : new SimpleDateFormat(dateFormat); _longNumberPattern = longNumberPattern; } /** * Create a new parser. */ private MongoJsonParser(String s, BSONCallback callback) { this.s = s; _callback = (callback == null) ? new JSONCallback() : callback; } /** * Parse an unknown type. * * @return Object the next item * @throws JSONParseException * if invalid JSON is found */ public Object parse() { return parse(null); } /** * Parse an unknown type. * * @return Object the next item * @throws JSONParseException * if invalid JSON is found */ protected Object parse(String name) { Object value = null; char current = get(); switch (current) { // null case 'n': read('n'); read('u'); read('l'); read('l'); value = null; break; // true case 't': read('t'); read('r'); read('u'); read('e'); value = true; break; // false case 'f': read('f'); read('a'); read('l'); read('s'); read('e'); value = false; break; // string case '\'': case '\"': String stringValue = parseString(); // Check for long value = stringValue; if (!StringUtils.isBlank(stringValue)) { if (_longNumberPattern != null) { Matcher m = _longNumberPattern.matcher(stringValue); if (m.matches()) { try { value = Long.parseLong(m.group(1)); } catch (Exception ex) { throw new JSONParseException(s, pos); } } } if (_dateFormat != null && _datePattern != null) { Matcher m = _datePattern.matcher(stringValue); if (m.matches()) { try { String dateString = m.group(1); if (dateString.endsWith("Z")) { // Simple date format does not recognise Z time zone so make it GMT dateString = dateString.substring(0, dateString.length() - 1) + "GMT"; } value = _dateFormat.parse(dateString); } catch (Exception ex) { throw new JSONParseException(ex, s, pos); } } } } break; // number case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': case '+': case '-': value = parseNumber(); break; // array case '[': value = parseArray(name); break; // object case '{': value = parseObject(name); break; default: throw new JSONParseException(s, pos); } return value; } /** * Parses an object for the form <i>{}</i> and <i>{ members }</i>. * * @return DBObject the next object * @throws JSONParseException * if invalid JSON is found */ public Object parseObject() { return parseObject(null); } /** * Parses an object for the form <i>{}</i> and <i>{ members }</i>. * * @return DBObject the next object * @throws JSONParseException * if invalid JSON is found */ protected Object parseObject(String name) { if (name != null) { _callback.objectStart(name); } else { _callback.objectStart(); } read('{'); @SuppressWarnings("unused") char current = get(); while (get() != '}') { String key = parseString(); read(':'); Object value = parse(key); doCallback(key, value); if ((current = get()) == ',') { read(','); } else { break; } } read('}'); return _callback.objectDone(); } protected void doCallback(String name, Object value) { if (value == null) { _callback.gotNull(name); } else if (value instanceof String) { _callback.gotString(name, (String) value); } else if (value instanceof Boolean) { _callback.gotBoolean(name, (Boolean) value); } else if (value instanceof Integer) { _callback.gotInt(name, (Integer) value); } else if (value instanceof Long) { _callback.gotLong(name, (Long) value); } else if (value instanceof Double) { _callback.gotDouble(name, (Double) value); } else if (value instanceof Date) { _callback.gotDate(name, ((Date) value).getTime()); } } /** * Read the current character, making sure that it is the expected character. Advances the pointer to the next * character. * * @param ch * the character expected * * @throws JSONParseException * if the current character does not match the given character */ public void read(char ch) { if (!check(ch)) { throw new JSONParseException(s, pos); } pos++; } public char read() { if (pos >= s.length()) throw new IllegalStateException("string done"); return s.charAt(pos++); } /** * Read the current character, making sure that it is a hexidecimal character. * * @throws JSONParseException * if the current character is not a hexidecimal character */ public void readHex() { if (pos < s.length() && ((s.charAt(pos) >= '0' && s.charAt(pos) <= '9') || (s.charAt(pos) >= 'A' && s.charAt(pos) <= 'F') || (s.charAt(pos) >= 'a' && s.charAt(pos) <= 'f'))) { pos++; } else { throw new JSONParseException(s, pos); } } /** * Checks the current character, making sure that it is the expected character. * * @param ch * the character expected * * @throws JSONParseException * if the current character does not match the given character */ public boolean check(char ch) { return get() == ch; } /** * Advances the position in the string past any whitespace. */ public void skipWS() { while (pos < s.length() && Character.isWhitespace(s.charAt(pos))) { pos++; } } /** * Returns the current character. Returns -1 if there are no more characters. * * @return the next character */ public char get() { skipWS(); if (pos < s.length()) return s.charAt(pos); return (char) -1; } /** * Parses a string. * * @return the next string. * @throws JSONParseException * if invalid JSON is found */ public String parseString() { char quot; if (check('\'')) quot = '\''; else if (check('\"')) quot = '\"'; else throw new JSONParseException(s, pos); char current; read(quot); StringBuilder buf = new StringBuilder(); int start = pos; while (pos < s.length() && (current = s.charAt(pos)) != quot) { if (current == '\\') { pos++; char x = get(); char special = 0; switch (x) { case 'u': { // decode unicode buf.append(s.substring(start, pos - 1)); pos++; int tempPos = pos; readHex(); readHex(); readHex(); readHex(); int codePoint = Integer.parseInt(s.substring(tempPos, tempPos + 4), 16); buf.append((char) codePoint); start = pos; continue; } case 'n': special = '\n'; break; case 'r': special = '\r'; break; case 't': special = '\t'; break; case 'b': special = '\b'; break; case '"': special = '\"'; break; case '\\': special = '\\'; break; } buf.append(s.substring(start, pos - 1)); if (special != 0) { pos++; buf.append(special); } start = pos; continue; } pos++; } read(quot); buf.append(s.substring(start, pos - 1)); return buf.toString(); } /** * Parses a number. * * @return the next number (int or double). * @throws JSONParseException * if invalid JSON is found */ public Number parseNumber() { @SuppressWarnings("unused") char current = get(); int start = this.pos; boolean isDouble = false; if (check('-') || check('+')) { pos++; } outer: while (pos < s.length()) { switch (s.charAt(pos)) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': pos++; break; case '.': isDouble = true; parseFraction(); break; case 'e': case 'E': isDouble = true; parseExponent(); break; default: break outer; } } if (isDouble) return Double.valueOf(s.substring(start, pos)); if (pos - start >= 10) return Long.valueOf(s.substring(start, pos)); return Integer.valueOf(s.substring(start, pos)); } /** * Advances the pointed through <i>.digits</i>. */ public void parseFraction() { // get past . pos++; outer: while (pos < s.length()) { switch (s.charAt(pos)) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': pos++; break; case 'e': case 'E': parseExponent(); break; default: break outer; } } } /** * Advances the pointer through the exponent. */ public void parseExponent() { // get past E pos++; if (check('-') || check('+')) { pos++; } outer: while (pos < s.length()) { switch (s.charAt(pos)) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': pos++; break; default: break outer; } } } /** * Parses the next array. * * @return the array * @throws JSONParseException * if invalid JSON is found */ public Object parseArray() { return parseArray(null); } /** * Parses the next array. * * @return the array * @throws JSONParseException * if invalid JSON is found */ protected Object parseArray(String name) { if (name != null) { _callback.arrayStart(name); } else { _callback.arrayStart(); } read('['); int i = 0; char current = get(); while (current != ']') { String elemName = String.valueOf(i++); Object elem = parse(elemName); doCallback(elemName, elem); if ((current = get()) == ',') { read(','); } else if (current == ']') { break; } else { throw new JSONParseException(s, pos); } } read(']'); return _callback.arrayDone(); } /** * Exception throw when invalid JSON is passed to JSONParser. * * This exception creates a message that points to the first offending character in the JSON string: * * <pre> * { "x" : 3, "y" : 4, some invalid json.... } * ^ * </pre> */ static class JSONParseException extends RuntimeException { private static final long serialVersionUID = -4415279469780082174L; String s; int pos; public String getMessage() { StringBuilder sb = new StringBuilder(); sb.append("\n"); sb.append(s); sb.append("\n"); for (int i = 0; i < pos; i++) { sb.append(" "); } sb.append("^"); return sb.toString(); } public JSONParseException(String s, int pos) { this.s = s; this.pos = pos; } public JSONParseException(Throwable ex, String s, int pos) { super(ex); this.s = s; this.pos = pos; } } }