Java tutorial
/** * Copyright (C) 2011 University of Washington * * 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.opendatakit.utils; import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.UnsupportedEncodingException; import java.text.DateFormat; import java.text.ParseException; import java.text.ParsePosition; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Locale; import java.util.TimeZone; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; import org.apache.commons.codec.binary.Base64; import org.apache.commons.lang3.CharEncoding; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.javarosa.core.model.utils.DateUtils; import org.opendatakit.constants.BasicConsts; /** * Useful methods for parsing boolean and date values and formatting dates. * * @author mitchellsundt@gmail.com * */ public class WebUtils { static final String IS_FORWARD_CURSOR_VALUE_TAG = "isForwardCursor"; static final String URI_LAST_RETURNED_VALUE_TAG = "uriLastReturnedValue"; static final String ATTRIBUTE_VALUE_TAG = "attributeValue"; static final String ATTRIBUTE_NAME_TAG = "attributeName"; static final String CURSOR_TAG = "cursor"; static final Log logger = LogFactory.getLog(WebUtils.class); /** * Date format pattern used to parse HTTP date headers in RFC 1123 format. * copied from apache.commons.lang.DateUtils */ private static final String PATTERN_RFC1123 = "EEE, dd MMM yyyy HH:mm:ss zzz"; /** * Date format pattern used to parse HTTP date headers in RFC 1036 format. * copied from apache.commons.lang.DateUtils */ private static final String PATTERN_RFC1036 = "EEEE, dd-MMM-yy HH:mm:ss zzz"; /** * Date format pattern used to parse HTTP date headers in ANSI C * <code>asctime()</code> format. copied from apache.commons.lang.DateUtils */ private static final String PATTERN_ASCTIME = "EEE MMM d HH:mm:ss yyyy"; private static final String PATTERN_DATE_TOSTRING = "EEE MMM dd HH:mm:ss zzz yyyy"; private static final String PATTERN_ISO8601 = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"; private static final String PATTERN_ISO8601_WITHOUT_ZONE = "yyyy-MM-dd'T'HH:mm:ss.SSS"; private static final String PATTERN_ISO8601_DATE = "yyyy-MM-ddZ"; private static final String PATTERN_ISO8601_TIME = "HH:mm:ss.SSSZ"; private static final String PATTERN_YYYY_MM_DD_DATE_ONLY_NO_TIME_DASH = "yyyy-MM-dd"; private static final String PATTERN_NO_DATE_TIME_ONLY = "HH:mm:ss.SSS"; private static final String PATTERN_GOOGLE_DOCS = "MM/dd/yyyy HH:mm:ss.SSS"; private static final String PATTERN_GOOGLE_DOCS_DATE_ONLY = "MM/dd/yyyy"; private static final String PURGE_DATE_FORMAT = "yyyy-MM-dd HH:mm:ss"; private WebUtils() { }; /** * Safely encode a string for use as a query parameter. * * @param rawString * @return encoded string */ public static String safeEncode(String rawString) { if (rawString == null || rawString.length() == 0) { return null; } try { ByteArrayOutputStream out = new ByteArrayOutputStream(); GZIPOutputStream gzip = new GZIPOutputStream(out); gzip.write(rawString.getBytes(CharEncoding.UTF_8)); gzip.finish(); gzip.close(); String candidate = Base64.encodeBase64URLSafeString(out.toByteArray()); return candidate; } catch (UnsupportedEncodingException e) { e.printStackTrace(); throw new IllegalArgumentException("Unexpected failure: " + e.toString()); } catch (IOException e) { e.printStackTrace(); throw new IllegalArgumentException("Unexpected failure: " + e.toString()); } } /** * Decode a safeEncode() string. * * @param encodedWebsafeString * @return rawString */ public static String safeDecode(String encodedWebsafeString) { if (encodedWebsafeString == null || encodedWebsafeString.length() == 0) { return encodedWebsafeString; } try { ByteArrayInputStream in = new ByteArrayInputStream( Base64.decodeBase64(encodedWebsafeString.getBytes(CharEncoding.UTF_8))); GZIPInputStream gzip = new GZIPInputStream(in); ByteArrayOutputStream out = new ByteArrayOutputStream(); int ch = gzip.read(); while (ch >= 0) { out.write(ch); ch = gzip.read(); } gzip.close(); out.flush(); out.close(); return new String(out.toByteArray(), CharEncoding.UTF_8); } catch (UnsupportedEncodingException e) { e.printStackTrace(); throw new IllegalArgumentException("Unexpected failure: " + e.toString()); } catch (IOException e) { e.printStackTrace(); throw new IllegalArgumentException("Unexpected failure: " + e.toString()); } } /** * Parse a string into a boolean value. Any of: * <ul> * <li>ok</li> * <li>yes</li> * <li>true</li> * <li>t</li> * <li>y</li> * </ul> * are interpretted as boolean true. * * @param value * @return */ public static final Boolean parseBoolean(String value) { Boolean b = null; if (value != null && value.length() != 0) { b = Boolean.FALSE; if (value.compareToIgnoreCase("ok") == 0) { b = Boolean.TRUE; } else if (value.compareToIgnoreCase("yes") == 0) { b = Boolean.TRUE; } else if (value.compareToIgnoreCase("true") == 0) { b = Boolean.TRUE; } else if (value.compareToIgnoreCase("T") == 0) { b = Boolean.TRUE; } else if (value.compareToIgnoreCase("Y") == 0) { b = Boolean.TRUE; } } return b; } private static final Date parseDateSubset(String value, String[] parsePatterns, Locale l, TimeZone tz) { // borrowed from apache.commons.lang.DateUtils... Date d = null; SimpleDateFormat parser = null; ParsePosition pos = new ParsePosition(0); for (int i = 0; i < parsePatterns.length; i++) { if (i == 0) { if (l == null) { parser = new SimpleDateFormat(parsePatterns[0]); } else { parser = new SimpleDateFormat(parsePatterns[0], l); } } else { parser.applyPattern(parsePatterns[i]); } parser.setTimeZone(tz); // enforce UTC for formats without timezones pos.setIndex(0); d = parser.parse(value, pos); if (d != null && pos.getIndex() == value.length()) { return d; } } return d; } /** * Parse a string into a datetime value. Tries the common Http formats, the * iso8601 format (used by Javarosa), the default formatting from * Date.toString(), and a time-only format. * * @param value * @return */ public static final Date parseDate(String value) { if (value == null || value.length() == 0) return null; String[] iso8601Pattern = new String[] { PATTERN_ISO8601 }; String[] localizedParsePatterns = new String[] { // try the common HTTP date formats that have time zones PATTERN_RFC1123, PATTERN_RFC1036, PATTERN_DATE_TOSTRING }; String[] localizedNoTzParsePatterns = new String[] { // ones without timezones... (will assume UTC) PATTERN_ASCTIME }; String[] tzParsePatterns = new String[] { PATTERN_ISO8601, PATTERN_ISO8601_DATE, PATTERN_ISO8601_TIME }; String[] noTzParsePatterns = new String[] { // ones without timezones... (will assume UTC) PATTERN_ISO8601_WITHOUT_ZONE, PATTERN_NO_DATE_TIME_ONLY, PATTERN_YYYY_MM_DD_DATE_ONLY_NO_TIME_DASH, PATTERN_GOOGLE_DOCS }; Date d = null; // iso8601 parsing is sometimes off-by-one when JR does it... d = parseDateSubset(value, iso8601Pattern, null, TimeZone.getTimeZone("GMT")); if (d != null) return d; // try to parse with the JavaRosa parsers d = DateUtils.parseDateTime(value); if (d != null) return d; d = DateUtils.parseDate(value); if (d != null) return d; d = DateUtils.parseTime(value); if (d != null) return d; // try localized and english text parsers (for Web headers and interactive // filter spec.) d = parseDateSubset(value, localizedParsePatterns, Locale.ENGLISH, TimeZone.getTimeZone("GMT")); if (d != null) return d; d = parseDateSubset(value, localizedParsePatterns, null, TimeZone.getTimeZone("GMT")); if (d != null) return d; d = parseDateSubset(value, localizedNoTzParsePatterns, Locale.ENGLISH, TimeZone.getTimeZone("GMT")); if (d != null) return d; d = parseDateSubset(value, localizedNoTzParsePatterns, null, TimeZone.getTimeZone("GMT")); if (d != null) return d; // try other common patterns that might not quite match JavaRosa parsers d = parseDateSubset(value, tzParsePatterns, null, TimeZone.getTimeZone("GMT")); if (d != null) return d; d = parseDateSubset(value, noTzParsePatterns, null, TimeZone.getTimeZone("GMT")); if (d != null) return d; // try the locale- and timezone- specific parsers { DateFormat formatter = DateFormat.getDateTimeInstance(); ParsePosition pos = new ParsePosition(0); d = formatter.parse(value, pos); if (d != null && pos.getIndex() == value.length()) { return d; } } { DateFormat formatter = DateFormat.getDateInstance(); ParsePosition pos = new ParsePosition(0); d = formatter.parse(value, pos); if (d != null && pos.getIndex() == value.length()) { return d; } } { DateFormat formatter = DateFormat.getTimeInstance(); ParsePosition pos = new ParsePosition(0); d = formatter.parse(value, pos); if (d != null && pos.getIndex() == value.length()) { return d; } } throw new IllegalArgumentException("Unable to parse the date: " + value); } public static final String asSubmissionDateTimeString(Date d) { if (d == null) return null; return DateUtils.formatDateTime(d, DateUtils.FORMAT_ISO8601); } public static final String asSubmissionDateOnlyString(Date d) { if (d == null) return null; return DateUtils.formatDate(d, DateUtils.FORMAT_ISO8601); } public static final String asSubmissionTimeOnlyString(Date d) { if (d == null) return null; return DateUtils.formatTime(d, DateUtils.FORMAT_ISO8601); } /** * Useful static method for constructing a UPPER_CASE persistence layer name * from a camelCase name. This inserts an underscore before a leading capital * letter and toUpper()s the resulting string. The transformation maps * multiple camelCase names to the same UPPER_CASE name so it is not * reversible. * <ul> * <li>thisURL => THIS_URL</li> * <li>thisUrl => THIS_URL</li> * <li>myFirstObject => MY_FIRST_OBJECT</li> * </ul> * * @param name * @return */ public static final String unCamelCase(String name) { StringBuilder b = new StringBuilder(); boolean lastCap = true; for (int i = 0; i < name.length(); ++i) { char ch = name.charAt(i); if (Character.isUpperCase(ch)) { if (!lastCap) { b.append('_'); } lastCap = true; b.append(ch); } else if (Character.isLetterOrDigit(ch)) { lastCap = false; b.append(Character.toUpperCase(ch)); } else { throw new IllegalArgumentException("Argument is not a valid camelCase name: " + name); } } return b.toString(); } /** * Return the GoogleDocs datetime string representation of a datetime. * * @param d * @return */ public static final String googleDocsDateTime(Date d) { if (d == null) return null; SimpleDateFormat asGoogleDoc = new SimpleDateFormat(PATTERN_GOOGLE_DOCS); asGoogleDoc.setTimeZone(TimeZone.getTimeZone("GMT")); return asGoogleDoc.format(d); } /** * Return the GoogleDocs date string representation of a date-only datetime. * * @param d * @return */ public static final String googleDocsDateOnly(Date d) { if (d == null) return null; SimpleDateFormat asGoogleDocDateOnly = new SimpleDateFormat(PATTERN_GOOGLE_DOCS_DATE_ONLY); asGoogleDocDateOnly.setTimeZone(TimeZone.getTimeZone("GMT")); return asGoogleDocDateOnly.format(d); } /** * Return the ISO8601 string representation of a date. * * @param d * @return */ public static final String iso8601Date(Date d) { if (d == null) return null; // SDF is not thread-safe SimpleDateFormat asGMTiso8601 = new SimpleDateFormat(PATTERN_ISO8601); // with // time // zone asGMTiso8601.setTimeZone(TimeZone.getTimeZone("GMT")); return asGMTiso8601.format(d); } /** * Return the RFC1123 string representation of a date. * * @param d * @return */ public static final String rfc1123Date(Date d) { if (d == null) return null; // SDF is not thread-safe SimpleDateFormat asGMTrfc1123 = new SimpleDateFormat(PATTERN_RFC1123); // with // time // zone asGMTrfc1123.setTimeZone(TimeZone.getTimeZone("GMT")); return asGMTrfc1123.format(d); } public static final String purgeDateString(Date d) { if (d == null) return null; // SDF is not thread-safe SimpleDateFormat purgeDateFormat = new SimpleDateFormat(PURGE_DATE_FORMAT); return purgeDateFormat.format(d); } public static final Date parsePurgeDateString(String str) throws ParseException { if (str == null) { return null; } // SDF is not thread-safe SimpleDateFormat purgeDateFormat = new SimpleDateFormat(PURGE_DATE_FORMAT); return purgeDateFormat.parse(str); } /** * Return a string with utf-8 characters replaced with backslash-uxxxx codes. * Useful for debugging. * * @param str * @return printable rendition of non-ASCII utf-8 characters. */ public static final String escapeUTF8String(String str) { StringBuilder b = new StringBuilder(); for (int i = 0; i < str.length(); ++i) { int code = str.codePointAt(i); if (code < 127) { b.append(str.charAt(i)); } else { String val = Integer.toHexString(code); while (val.length() < 4) { val = '0' + val; } b.append("\\u" + val); } } return b.toString(); } public static String readResponse(HttpResponse resp) throws IOException { HttpEntity e = resp.getEntity(); if (e != null) { return WebUtils.readResponseHelper(e.getContent()); } return BasicConsts.EMPTY_STRING; } private static String readResponseHelper(InputStream content) { StringBuffer response = new StringBuffer(); if (content != null) { // TODO: this section of code is possibly causing 'WARNING: Going to // buffer // response body of large or unknown size. Using getResponseBodyAsStream // instead is recommended.' // The WARNING is most likely only happening when running appengine // locally, // but we should investigate to make sure BufferedReader reader = null; InputStreamReader isr = null; try { reader = new BufferedReader(isr = new InputStreamReader(content, BasicConsts.UTF8_ENCODE)); String responseLine; while ((responseLine = reader.readLine()) != null) { response.append(responseLine); } } catch (UnsupportedEncodingException ex) { ex.printStackTrace(); } catch (IllegalStateException ex) { ex.printStackTrace(); } catch (IOException ex) { ex.printStackTrace(); } finally { try { if (reader != null) { reader.close(); } } catch (IOException ex) { // no-op } try { if (isr != null) { isr.close(); } } catch (IOException ex) { // no-op } } } return response.toString(); } }