Printing and parsing of dates and times

[yegor256]

To be honest, I'm sick of date parsing and printing in Java 8 Date and Time API. How about we create our own object-oriented one at org.cactoos.time? Here is how it should work, I believe.

Printing:

String text = new DateAsText(new Date(), "%Y-%m-%d").asString();
String text = new DateAsText(System.currentTimeMillis(), "%Y-%m-%d").asString();
String text = new DateAsText(ZonedDateTime.now()).asString(); // ISO 8601 is the default one

Parsing:

Date date = new DateOf("2017-10-17", "%Y-%m-%d").value();
Date date = new DateOf("October 16, 2017", DateTimeFormatter.ISO_LOCAL_DATE).value();

With time zones:

String text = new DateAsText(new Date(), "%Y-%m-%d", "PST").asString();
Date date = new DateOf("2017-01-01", "%Y-%m-%d", ZoneOffset.UTC).value();

That's it.

Later, we can create, for example:

Date date = new Shifted(date, 5, "month").value();

[Timmeey]

Date date = new Shifted(date, 5, "month").value();

Please don't use "String" (month) as identifier for the unit. Noone can ever get the naming right. Was ist capitalized? Does ms exists as a uni? or was it even ms not MilliSecond?

Also i'm always struggling with date formatting since i can NEVER remember what character means what. Was MM minute or Month, or was it the month number or month name?

Maybe we could do something with enums here? At least the SHIFTING unit can definitely be done with an enum. Not so sure about the formatting yet.

[yegor256]

@Timmeey we can use java.time.temporal.ChronoUnit enum: https://docs.oracle.com/javase/8/docs/api/java/time/temporal/ChronoUnit.html

[svendiedrichsen]

@yegor256 I would like to contribute to this.

[yegor256]

@svendiedrichsen please, go ahead, but slowly. Don't make big pull requests, since they may get stuck in reviews.

[svendiedrichsen]

@yegor256 Sorry for this. But I didn't think of 2 classes and 2 tests being such a big PR.

[svendiedrichsen]

@yegor256 Can this be closed now?

[yegor256]

@svendiedrichsen yes, many thanks!