Timestamp (JSimpleDB Raft Key/Value Store 2.4.1 API)

java.lang.Object
- org.jsimpledb.kv.raft.Timestamp

All Implemented Interfaces:

Comparable<Timestamp>
```
public class Timestamp
extends Object
implements Comparable<Timestamp>
```
Represents a relative timestamp in milliseconds.
Values are stored as an unsigned 32 bit integer, which therefore recycles after 2³² milliseconds (about 48 days). Two values to be compared must have been generated within 24 days of each other to be ordered correctly.
This class uses System.nanoTime(), not System.currentTimeMillis(), and so is immune to changes in the system clock. To facilitate debugging, the zero mark is set at class initialization time.
Instances are immutable.

Field Summary

Fields
Modifier and Type Field and Description

static Comparator<Timestamp> NULL_FIRST_SORT
Sorts possibly null Timestamps in chronological order, with null sorting first.

Fields
Modifier and Type	Field and Description
`static Comparator<Timestamp>`	`NULL_FIRST_SORT` Sorts possibly null `Timestamp`s in chronological order, with null sorting first.

Constructor Summary

Constructors
Constructor and Description

Timestamp()
Construtor returning the current time.

Timestamp(int millis)
Constructor.

Constructors
Constructor and Description
`Timestamp()` Construtor returning the current time.
`Timestamp(int millis)` Constructor.

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`compareTo(Timestamp that)` Compare two instances, where "smaller" means earlier in time.
`boolean`	`equals(Object obj)`
`int`	`getMillis()` Get the relative milliseconds value contained by this instance.
`int`	`hashCode()`
`boolean`	`hasOccurred()` Determine whether this timestamp is in the past or the future.
`boolean`	`isRolloverDanger()` Determine whether this timestamp is so far in the past that it is in danger of rolling over to the future as time continues to move forward.
`Timestamp`	`offset(int offset)` Return this timestamp offset by the given amount.
`int`	`offsetFrom(Timestamp base)` Get the number of milliseconds this instance is offset from the given instance.
`int`	`offsetFromNow()` Get the number of milliseconds this instance is offset from the current time.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - NULL_FIRST_SORT
```
public static final Comparator<Timestamp> NULL_FIRST_SORT
```
    Sorts possibly null Timestamps in chronological order, with null sorting first.
    All non-null Timestamps must be contained within a single 2³¹-1 range; otherwise results are undefined.
- Constructor Detail
  - Timestamp
```
public Timestamp()
```
    Construtor returning the current time.
  - Timestamp
```
public Timestamp(int millis)
```
    Constructor.
    
    Parameters:
    millis - relative milliseconds value from getMillis()
- Method Detail
  - getMillis
```
public int getMillis()
```
    Get the relative milliseconds value contained by this instance.
    
    Returns:
    relative millisecond value
  - offsetFromNow
```
public int offsetFromNow()
```
    Get the number of milliseconds this instance is offset from the current time.
    A positive offset means this instance is in the future.
    
    Returns:
    relative millisecond offset
  - offsetFrom
```
public int offsetFrom(Timestamp base)
```
    Get the number of milliseconds this instance is offset from the given instance.
    A positive offset means this instance is after base.
    
    Parameters:
    base - base timestamp
    
    Returns:
    relative millisecond offset
    
    Throws:
    
    IllegalArgumentException - if base is null
  - offset
```
public Timestamp offset(int offset)
```
    Return this timestamp offset by the given amount.
    
    Parameters:
    offset - offset in milliseconds
    
    Returns:
    adjusted timestamp
  - hasOccurred
```
public boolean hasOccurred()
```
    Determine whether this timestamp is in the past or the future.
    
    Returns:
    true if this timestamp is in the past
  - isRolloverDanger
```
public boolean isRolloverDanger()
```
    Determine whether this timestamp is so far in the past that it is in danger of rolling over to the future as time continues to move forward.
    This returns true if this timestamp is within 5% of the roll-over point relative to the current time. This would represent a time approximately 22.8 days in the past.
    
    Returns:
    true if this timestamp's offset is dangerously negative
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - compareTo
```
public int compareTo(Timestamp that)
```
    Compare two instances, where "smaller" means earlier in time.
    Note: because timestamps recycle every 48 days, this method does not totally order instances.
    
    Specified by:
    
    compareTo in interface Comparable<Timestamp>
    
    Parameters:
    that - timestamp to compare with
    
    Throws:
    
    IllegalArgumentException - if this instance and that differ by exactly 2³¹ milliseconds
    
    NullPointerException - if that is null

Class Timestamp

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

NULL_FIRST_SORT

Constructor Detail

Timestamp

Timestamp

Method Detail

getMillis

offsetFromNow

offsetFrom

offset

hasOccurred

isRolloverDanger

equals

hashCode

toString

compareTo