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Base algos, data structures and utilities
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/*
* Copyright (c) 2018 Vikash Madhow
*/
package ma.vi.base.util;
import ma.vi.base.string.Escape;
import ma.vi.base.tuple.T2;
import java.text.DateFormat;
import java.text.DecimalFormat;
import java.text.Format;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import static java.lang.Integer.parseInt;
/**
* Utilities for converting values for one type to another.
*
* @author [email protected]
*/
public class Convert {
/**
* Returns true if the text could be a regular expression. This
* is approximate as it only tests for common characters which appears
* commonly in regular expressions (such as *).
*/
public static boolean couldBeRegex(String text) {
return text.indexOf('*') != -1 || text.indexOf('+') != -1 ||
text.indexOf('|') != -1 || text.indexOf('?') != -1 ||
text.indexOf('[') != -1 || text.indexOf(']') != -1 ||
text.indexOf('\\') != -1 || text.indexOf('$') != -1 ||
text.indexOf('^') != -1;
}
/**
* Converts a value to string, applying a default format.
*/
public static String defaultFormat(Object value) {
if (value == null) {
return null;
} else {
Format formatter = defaultFormatter(value.getClass());
if (formatter != null) {
return formatter.format(value);
} else {
return value.toString();
}
}
}
/**
* Returns a format object for the specified target type. Returns null if no appropriate
* formatter found.
*/
public static Format defaultFormatter(Class type) {
if (Date.class.isAssignableFrom(type)) {
return DATE_FORMATTER;
} else if (Number.class.isAssignableFrom(type)) {
if (Numbers.isIntegral(type)) {
return INTEGER_FORMATTER;
} else {
return DECIMAL_FORMATTER;
}
}
return null;
}
public static Object convert(Object value, Class type) {
if (value == null) {
return null;
} else if (type.isAssignableFrom(value.getClass())) {
return value;
} else {
return convert(String.valueOf(value), type);
}
}
/**
* Utility method to convert a string to an object.
*/
public static Object convert(String text, Class type) {
try {
if (Number.class.isAssignableFrom(type)) {
if (Numbers.isIntegral(type)) {
// remove fractional part which will be ignored
int pos = text.indexOf('.');
if (pos != -1) {
text = text.substring(0, pos);
if (text.length() == 0) {
text = "0";
}
}
}
return type.getConstructor(String.class).newInstance(text);
} else if (Boolean.class.isAssignableFrom(type)) {
return type.getConstructor(String.class).newInstance(text);
} else if (String.class.isAssignableFrom(type)) {
return text;
} else if (Character.class.isAssignableFrom(type)) {
return text.charAt(0);
} else if (Date.class.isAssignableFrom(type)) {
return convertDate(text);
}
} catch (Exception e) {
throw e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e);
}
throw new RuntimeException(type + " is not supported");
}
/**
* Converts text value to the specified Esql type.
*/
public static Object toType(Object value, String type) {
if (type == null || type.equals("variable")) {
return value;
} else if (type.equals("bool")) {
if (value == null) {
return null;
} else if (value instanceof String) {
String v = ((String) value).trim().toLowerCase();
return v.startsWith("t") || v.startsWith("y");
} else if (value instanceof Number) {
return ((Number) value).intValue() != 0;
} else {
return true;
}
} else if (value instanceof String) {
if (type.equals("byte")
|| type.equals("short")
|| type.equals("int")
|| type.equals("long")
|| type.equals("float")
|| type.equals("double")) {
return Numbers.convert((String) value);
} else if (type.startsWith("date")) {
return convertDate((String) value);
} else {
return value;
}
} else if (type.equals("string")) {
if (value == null) {
return null;
} else {
return value.toString();
}
} else {
return value;
}
}
/**
* Converts the value into a form that can be concatenated into a SQL statement.
*/
public static String sqlParameter(Object value) {
if (value == null) {
return "NULL";
} else if (value instanceof Boolean) {
boolean v = (Boolean) value;
return v ? "TRUE" : "FALSE";
} else if (value instanceof Date) {
return Dates.toSqlDateLiteral((Date) value);
} else if (value instanceof Number) {
return value.toString();
} else if (value instanceof Character) {
return "'" + value + "'";
} else if (value instanceof String) {
return "'" + Escape.escapeSqlString((String) value) + "'";
} else {
throw new IllegalArgumentException(value.getClass() + " cannot be converted to a form supported by SQL");
}
}
/**
* Attempts to convert the value using most common formats.
*
* @param date The value to convert.
* @return The converted value or null if the value was null.
* @throws IllegalArgumentException If the value could not be converted to a date.
*/
public static Date convertDate(String date) throws IllegalArgumentException {
T2 converted = convertInternal(date);
if (converted.b) {
return converted.a;
} else {
throw new IllegalArgumentException("'" + date + "' could not be converted to a date");
}
}
/**
* Returns true if the provided date in string format can be converted to a valid date.
*/
public static boolean canConvert(String date) {
if (date == null) {
return true;
} else {
return convertInternal(date).b;
}
}
/**
* Converts the string value to a date. Return a pair, where the first value is
* the converted date if successfully converted (or null otherwise), and the second
* value is true when the conversion is successful, or false otherwise.
*/
private static T2 convertInternal(String value) {
if (value != null) {
// remove all unnecessary characters prior to conversion
boolean yearFound = false;
boolean monthFound = false;
boolean dayFound = false;
int probableMonthStart = -1;
int probableMonthEnd = -1;
StringBuilder compressed = new StringBuilder();
Matcher matcher = WORDS_NUMBERS.matcher(value);
while (matcher.find()) {
String token = value.substring(matcher.start(), matcher.end());
if (YEAR_PATTERN.matcher(token).matches()) {
yearFound = true;
compressed.insert(0, token + " ");
// push probable month position correspondingly
if (probableMonthStart != -1) {
probableMonthStart += token.length() + 1;
probableMonthEnd += token.length() + 1;
}
} else {
if (MONTH_PATTERN.matcher(token).matches()) {
monthFound = true;
} else if (DAY_OR_MONTH_PATTERN.matcher(token).matches()) {
// if we have already seen a month
if (monthFound) {
dayFound = true;
} else {
int number = parseInt(token);
if ((dayFound || yearFound) && probableMonthStart == -1 && number > 0 && number <= 12) {
// since we have already seen the year, this is a probable month
probableMonthStart = compressed.length();
probableMonthEnd = probableMonthStart + token.length();
} else {
dayFound = true;
}
}
}
compressed.append(token).append(' ');
}
}
if (!monthFound && probableMonthStart != -1) {
int month = parseInt(compressed.substring(probableMonthStart, probableMonthEnd));
compressed.delete(probableMonthStart, probableMonthEnd);
compressed.insert(probableMonthStart, Month.get(month).name);
}
String reformatted = compressed.toString().trim();
DateFormat[] formats = yearFound ? DATE_FORMATS_WITH_FOUR_DIGITS_YEAR : DATE_FORMATS_WITH_TWO_DIGITS_YEAR;
for (DateFormat formatter : formats) {
try {
Date date = formatter.parse(reformatted);
return new T2<>(date, Boolean.TRUE);
} catch (Exception ignore) {
}
}
if (reformatted.length() == 8) {
try {
int year = parseInt(reformatted.substring(0, 4));
int month = parseInt(reformatted.substring(4, 6));
DateFormat formatter;
if (year >= 1900 && year <= 2100 && month >= 1 && month <= 12) {
formatter = yyyyMMdd;
} else {
formatter = ddMMyyyy;
}
Date date = formatter.parse(reformatted);
return new T2<>(date, Boolean.TRUE);
} catch (Exception ignore) {
}
}
return new T2<>(null, Boolean.FALSE);
}
return new T2<>(null, Boolean.TRUE);
}
private static final DateFormat yyyyMMdd = new SimpleDateFormat("yyyyMMdd");
private static final DateFormat ddMMyyyy = new SimpleDateFormat("ddMMyyyy");
/**
* Common date formats used for 4-digit years.
*/
public static final DateFormat[] DATE_FORMATS_WITH_FOUR_DIGITS_YEAR = {
// date and time in 24-hour with seconds and time zone
new SimpleDateFormat("yyyy MMM d HH mm ss z"),
new SimpleDateFormat("yyyy d MMM HH mm ss z"),
// date and time in 12-hour (am, pm) with seconds
new SimpleDateFormat("yyyy MMM d KK mm ss a"),
new SimpleDateFormat("yyyy d MMM KK mm ss a"),
// date and time in 24-hour with seconds
new SimpleDateFormat("yyyy MMM d HH mm ss"),
new SimpleDateFormat("yyyy d MMM HH mm ss"),
// date and time in 12-hour (am, pm) without seconds
new SimpleDateFormat("yyyy MMM d KK mm a"),
new SimpleDateFormat("yyyy d MMM KK mm a"),
// date and time in 24-hour without seconds with timezone
new SimpleDateFormat("yyyy MMM d HH mm z"),
new SimpleDateFormat("yyyy d MMM HH mm z"),
// date and time in 24-hour without seconds
new SimpleDateFormat("yyyy MMM d HH mm"),
new SimpleDateFormat("yyyy d MMM HH mm"),
// date only, no time
new SimpleDateFormat("yyyy MMM d"),
new SimpleDateFormat("yyyy d MMM"),
};
/**
* Common date formats used for 2-digits years.
*/
public static final DateFormat[] DATE_FORMATS_WITH_TWO_DIGITS_YEAR =
{
// date and time in 24-hour with seconds and time zone
new SimpleDateFormat("d MMM yy HH mm ss z"),
new SimpleDateFormat("MMM d yy HH mm ss z"),
// date and time in 12-hour (am, pm) with seconds
new SimpleDateFormat("d MMM yy KK mm ss a"),
new SimpleDateFormat("MMM d yy KK mm ss a"),
// date and time in 24-hour with seconds
new SimpleDateFormat("d MMM yy HH mm ss"),
new SimpleDateFormat("MMM d yy HH mm ss"),
// date and time in 12-hour (am, pm) without seconds
new SimpleDateFormat("d MMM yy KK mm a"),
new SimpleDateFormat("MMM d yy KK mm a"),
// date and time in 24-hour without seconds with timezone
new SimpleDateFormat("d MMM yy HH mm z"),
new SimpleDateFormat("MMM d yy HH mm z"),
// date and time in 24-hour without seconds
new SimpleDateFormat("d MMM yy HH mm"),
new SimpleDateFormat("MMM d yy HH mm"),
// date only, no time
new SimpleDateFormat("d MMM yy"),
new SimpleDateFormat("MMM d yy"),
};
public static final Pattern WORDS_NUMBERS = Pattern.compile("(?i)[a-z]+|[0-9]+");
/**
* A formatter for printing the month and year of a date.
*/
public static final SimpleDateFormat MONTH_YEAR = new SimpleDateFormat("MMMM, yyyy");
/**
* A pattern for matching years.
*/
public static final Pattern YEAR_PATTERN = Pattern.compile("\\d{4}");
/**
* A numeric day or month.
*/
public static final Pattern DAY_OR_MONTH_PATTERN = Pattern.compile("\\d{1,2}");
/**
* A pattern for matching with the name of a month.
*/
public static final Pattern MONTH_PATTERN = Pattern.compile(
"(?i)j[a-z]*|f[a-z]*|m[a-z]*|a[a-z]*|s[a-z]*|o[a-z]*|n[a-z]*|d[a-z]*");
/**
* Default date format with unbreakable hyphens characters (\u2011)
* separating the date components.
*/
public static final String DATE_FORMAT = "dd-MMM-yyyy"; // "dd\u2011MMM\u2011yy";
public static final String ISO_DATE_FORMAT = "yyyy-MM-dd";
/**
* Format for time.
*/
public static final String TIME_FORMAT = "HH:mm";
/**
* Format for timestamps.
*/
public static final String TIMESTAMP_FORMAT = DATE_FORMAT + " " + TIME_FORMAT;
/**
* Integer format.
*/
public static final String INTEGER_FORMAT = "############################,##0";
/**
* Decimal format.
*/
public static final String DECIMAL_FORMAT = "############################,##0.00";
/**
* Integer formatter.
*/
public static final DecimalFormat INTEGER_FORMATTER = new DecimalFormat(INTEGER_FORMAT);
/**
* Decimal formatter.
*/
public static final DecimalFormat DECIMAL_FORMATTER = new DecimalFormat(DECIMAL_FORMAT);
/**
* Default date formatter.
*/
public static final SimpleDateFormat DATE_FORMATTER = new SimpleDateFormat(DATE_FORMAT);
public static final SimpleDateFormat ISO_DATE_FORMATTER = new SimpleDateFormat(ISO_DATE_FORMAT);
/**
* Default date formatter.
*/
public static final SimpleDateFormat TIME_FORMATTER = new SimpleDateFormat(TIME_FORMAT);
public static final SimpleDateFormat TIMESTAMP_FORMATTER = new SimpleDateFormat(TIMESTAMP_FORMAT);
}
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