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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.cassandra.cql3;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import com.google.common.base.Objects;
import org.apache.cassandra.serializers.MarshalException;
import static org.apache.cassandra.cql3.statements.RequestValidations.checkTrue;
import static org.apache.cassandra.cql3.statements.RequestValidations.invalidRequest;
/**
* Represents a duration. A durations store separately months, days, and seconds due to the fact that
* the number of days in a month varies, and a day can have 23 or 25 hours if a daylight saving is involved.
*/
public final class Duration
{
public static final long NANOS_PER_MICRO = 1000L;
public static final long NANOS_PER_MILLI = 1000 * NANOS_PER_MICRO;
public static final long NANOS_PER_SECOND = 1000 * NANOS_PER_MILLI;
public static final long NANOS_PER_MINUTE = 60 * NANOS_PER_SECOND;
public static final long NANOS_PER_HOUR = 60 * NANOS_PER_MINUTE;
public static final int DAYS_PER_WEEK = 7;
public static final int MONTHS_PER_YEAR = 12;
/**
* The Regexp used to parse the duration provided as String.
*/
private static final Pattern STANDARD_PATTERN =
Pattern.compile("\\G(\\d+)(y|Y|mo|MO|mO|Mo|w|W|d|D|h|H|s|S|ms|MS|mS|Ms|us|US|uS|Us|µs|µS|ns|NS|nS|Ns|m|M)");
/**
* The Regexp used to parse the duration when provided in the ISO 8601 format with designators.
*/
private static final Pattern ISO8601_PATTERN =
Pattern.compile("P((\\d+)Y)?((\\d+)M)?((\\d+)D)?(T((\\d+)H)?((\\d+)M)?((\\d+)S)?)?");
/**
* The Regexp used to parse the duration when provided in the ISO 8601 format with designators.
*/
private static final Pattern ISO8601_WEEK_PATTERN = Pattern.compile("P(\\d+)W");
/**
* The Regexp used to parse the duration when provided in the ISO 8601 alternative format.
*/
private static final Pattern ISO8601_ALTERNATIVE_PATTERN =
Pattern.compile("P(\\d{4})-(\\d{2})-(\\d{2})T(\\d{2}):(\\d{2}):(\\d{2})");
/**
* The number of months.
*/
private final int months;
/**
* The number of days.
*/
private final int days;
/**
* The number of nanoseconds.
*/
private final long nanoseconds;
/**
* Creates a duration. A duration can be negative.
* In this case all the non zero values must be negatives.
*
* @param months the number of months
* @param days the number of days
* @param nanoseconds the number of nanoseconds
*/
private Duration(int months, int days, long nanoseconds)
{
// Makes sure that all the values are negatives if one of them is
assert (months >= 0 && days >= 0 && nanoseconds >= 0)
|| ((months <= 0 && days <=0 && nanoseconds <=0));
this.months = months;
this.days = days;
this.nanoseconds = nanoseconds;
}
public static Duration newInstance(int months, int days, long nanoseconds)
{
return new Duration(months, days, nanoseconds);
}
/**
* Converts a String into a duration.
* The accepted formats are:
*
* - multiple digits followed by a time unit like: 12h30m where the time unit can be:
*
* - {@code y}: years
* - {@code m}: months
* - {@code w}: weeks
* - {@code d}: days
* - {@code h}: hours
* - {@code m}: minutes
* - {@code s}: seconds
* - {@code ms}: milliseconds
* - {@code us} or {@code µs}: microseconds
* - {@code ns}: nanoseconds
*
*
* - ISO 8601 format: P[n]Y[n]M[n]DT[n]H[n]M[n]S or P[n]W
* - ISO 8601 alternative format: P[YYYY]-[MM]-[DD]T[hh]:[mm]:[ss]
*
*
* @param input the String to convert
* @return a number of nanoseconds
*/
public static Duration from(String input)
{
boolean isNegative = input.startsWith("-");
String source = isNegative ? input.substring(1) : input;
if (source.startsWith("P"))
{
if (source.endsWith("W"))
return parseIso8601WeekFormat(isNegative, source);
if (source.contains("-"))
return parseIso8601AlternativeFormat(isNegative, source);
return parseIso8601Format(isNegative, source);
}
return parseStandardFormat(isNegative, source);
}
private static Duration parseIso8601Format(boolean isNegative, String source)
{
Matcher matcher = ISO8601_PATTERN.matcher(source);
if (!matcher.matches())
throw invalidRequest("Unable to convert '%s' to a duration", source);
Builder builder = new Builder(isNegative);
if (matcher.group(1) != null)
builder.addYears(groupAsLong(matcher, 2));
if (matcher.group(3) != null)
builder.addMonths(groupAsLong(matcher, 4));
if (matcher.group(5) != null)
builder.addDays(groupAsLong(matcher, 6));
// Checks if the String contains time information
if (matcher.group(7) != null)
{
if (matcher.group(8) != null)
builder.addHours(groupAsLong(matcher, 9));
if (matcher.group(10) != null)
builder.addMinutes(groupAsLong(matcher, 11));
if (matcher.group(12) != null)
builder.addSeconds(groupAsLong(matcher, 13));
}
return builder.build();
}
private static Duration parseIso8601AlternativeFormat(boolean isNegative, String source)
{
Matcher matcher = ISO8601_ALTERNATIVE_PATTERN.matcher(source);
if (!matcher.matches())
throw invalidRequest("Unable to convert '%s' to a duration", source);
return new Builder(isNegative).addYears(groupAsLong(matcher, 1))
.addMonths(groupAsLong(matcher, 2))
.addDays(groupAsLong(matcher, 3))
.addHours(groupAsLong(matcher, 4))
.addMinutes(groupAsLong(matcher, 5))
.addSeconds(groupAsLong(matcher, 6))
.build();
}
private static Duration parseIso8601WeekFormat(boolean isNegative, String source)
{
Matcher matcher = ISO8601_WEEK_PATTERN.matcher(source);
if (!matcher.matches())
throw invalidRequest("Unable to convert '%s' to a duration", source);
return new Builder(isNegative).addWeeks(groupAsLong(matcher, 1))
.build();
}
private static Duration parseStandardFormat(boolean isNegative, String source)
{
Matcher matcher = STANDARD_PATTERN.matcher(source);
if (!matcher.find())
throw invalidRequest("Unable to convert '%s' to a duration", source);
Builder builder = new Builder(isNegative);
boolean done = false;
do
{
long number = groupAsLong(matcher, 1);
String symbol = matcher.group(2);
add(builder, number, symbol);
done = matcher.end() == source.length();
}
while (matcher.find());
if (!done)
throw invalidRequest("Unable to convert '%s' to a duration", source);
return builder.build();
}
private static long groupAsLong(Matcher matcher, int group)
{
return Long.parseLong(matcher.group(group));
}
private static Builder add(Builder builder, long number, String symbol)
{
switch (symbol.toLowerCase())
{
case "y": return builder.addYears(number);
case "mo": return builder.addMonths(number);
case "w": return builder.addWeeks(number);
case "d": return builder.addDays(number);
case "h": return builder.addHours(number);
case "m": return builder.addMinutes(number);
case "s": return builder.addSeconds(number);
case "ms": return builder.addMillis(number);
case "us":
case "µs": return builder.addMicros(number);
case "ns": return builder.addNanos(number);
}
throw new MarshalException(String.format("Unknown duration symbol '%s'", symbol));
}
public int getMonths()
{
return months;
}
public int getDays()
{
return days;
}
public long getNanoseconds()
{
return nanoseconds;
}
@Override
public int hashCode()
{
return Objects.hashCode(days, months, nanoseconds);
}
@Override
public boolean equals(Object obj)
{
if (!(obj instanceof Duration))
return false;
Duration other = (Duration) obj;
return days == other.days
&& months == other.months
&& nanoseconds == other.nanoseconds;
}
@Override
public String toString()
{
StringBuilder builder = new StringBuilder();
if (months < 0 || days < 0 || nanoseconds < 0)
builder.append('-');
long remainder = append(builder, Math.abs(months), MONTHS_PER_YEAR, "y");
append(builder, remainder, 1, "mo");
append(builder, Math.abs(days), 1, "d");
if (nanoseconds != 0)
{
remainder = append(builder, Math.abs(nanoseconds), NANOS_PER_HOUR, "h");
remainder = append(builder, remainder, NANOS_PER_MINUTE, "m");
remainder = append(builder, remainder, NANOS_PER_SECOND, "s");
remainder = append(builder, remainder, NANOS_PER_MILLI, "ms");
remainder = append(builder, remainder, NANOS_PER_MICRO, "us");
append(builder, remainder, 1, "ns");
}
return builder.toString();
}
/**
* Appends the result of the division to the specified builder if the dividend is not zero.
*
* @param builder the builder to append to
* @param dividend the dividend
* @param divisor the divisor
* @param unit the time unit to append after the result of the division
* @return the remainder of the division
*/
private static long append(StringBuilder builder, long dividend, long divisor, String unit)
{
if (dividend == 0 || dividend < divisor)
return dividend;
builder.append(dividend / divisor).append(unit);
return dividend % divisor;
}
private static class Builder
{
/**
* {@code true} if the duration is a negative one, {@code false} otherwise.
*/
private final boolean isNegative;
/**
* The number of months.
*/
private int months;
/**
* The number of days.
*/
private int days;
/**
* The number of nanoseconds.
*/
private long nanoseconds;
/**
* We need to make sure that the values for each units are provided in order.
*/
private int currentUnitIndex;
public Builder(boolean isNegative)
{
this.isNegative = isNegative;
}
/**
* Adds the specified amount of years.
*
* @param numberOfYears the number of years to add.
* @return this {@code Builder}
*/
public Builder addYears(long numberOfYears)
{
validateOrder(1);
validateMonths(numberOfYears, MONTHS_PER_YEAR);
months += numberOfYears * MONTHS_PER_YEAR;
return this;
}
/**
* Adds the specified amount of months.
*
* @param numberOfMonths the number of months to add.
* @return this {@code Builder}
*/
public Builder addMonths(long numberOfMonths)
{
validateOrder(2);
validateMonths(numberOfMonths, 1);
months += numberOfMonths;
return this;
}
/**
* Adds the specified amount of weeks.
*
* @param numberOfWeeks the number of weeks to add.
* @return this {@code Builder}
*/
public Builder addWeeks(long numberOfWeeks)
{
validateOrder(3);
validateDays(numberOfWeeks, DAYS_PER_WEEK);
days += numberOfWeeks * DAYS_PER_WEEK;
return this;
}
/**
* Adds the specified amount of days.
*
* @param numberOfDays the number of days to add.
* @return this {@code Builder}
*/
public Builder addDays(long numberOfDays)
{
validateOrder(4);
validateDays(numberOfDays, 1);
days += numberOfDays;
return this;
}
/**
* Adds the specified amount of hours.
*
* @param numberOfHours the number of hours to add.
* @return this {@code Builder}
*/
public Builder addHours(long numberOfHours)
{
validateOrder(5);
validateNanos(numberOfHours, NANOS_PER_HOUR);
nanoseconds += numberOfHours * NANOS_PER_HOUR;
return this;
}
/**
* Adds the specified amount of minutes.
*
* @param numberOfMinutes the number of minutes to add.
* @return this {@code Builder}
*/
public Builder addMinutes(long numberOfMinutes)
{
validateOrder(6);
validateNanos(numberOfMinutes, NANOS_PER_MINUTE);
nanoseconds += numberOfMinutes * NANOS_PER_MINUTE;
return this;
}
/**
* Adds the specified amount of seconds.
*
* @param numberOfSeconds the number of seconds to add.
* @return this {@code Builder}
*/
public Builder addSeconds(long numberOfSeconds)
{
validateOrder(7);
validateNanos(numberOfSeconds, NANOS_PER_SECOND);
nanoseconds += numberOfSeconds * NANOS_PER_SECOND;
return this;
}
/**
* Adds the specified amount of milliseconds.
*
* @param numberOfMillis the number of milliseconds to add.
* @return this {@code Builder}
*/
public Builder addMillis(long numberOfMillis)
{
validateOrder(8);
validateNanos(numberOfMillis, NANOS_PER_MILLI);
nanoseconds += numberOfMillis * NANOS_PER_MILLI;
return this;
}
/**
* Adds the specified amount of microseconds.
*
* @param numberOfMicros the number of microseconds to add.
* @return this {@code Builder}
*/
public Builder addMicros(long numberOfMicros)
{
validateOrder(9);
validateNanos(numberOfMicros, NANOS_PER_MICRO);
nanoseconds += numberOfMicros * NANOS_PER_MICRO;
return this;
}
/**
* Adds the specified amount of nanoseconds.
*
* @param numberOfNanos the number of nanoseconds to add.
* @return this {@code Builder}
*/
public Builder addNanos(long numberOfNanos)
{
validateOrder(10);
validateNanos(numberOfNanos, 1);
nanoseconds += numberOfNanos;
return this;
}
/**
* Validates that the total number of months can be stored.
* @param units the number of units that need to be added
* @param monthsPerUnit the number of days per unit
*/
private void validateMonths(long units, int monthsPerUnit)
{
validate(units, (Integer.MAX_VALUE - months) / monthsPerUnit, "months");
}
/**
* Validates that the total number of days can be stored.
* @param units the number of units that need to be added
* @param daysPerUnit the number of days per unit
*/
private void validateDays(long units, int daysPerUnit)
{
validate(units, (Integer.MAX_VALUE - days) / daysPerUnit, "days");
}
/**
* Validates that the total number of nanoseconds can be stored.
* @param units the number of units that need to be added
* @param nanosPerUnit the number of nanoseconds per unit
*/
private void validateNanos(long units, long nanosPerUnit)
{
validate(units, (Long.MAX_VALUE - nanoseconds) / nanosPerUnit, "nanoseconds");
}
/**
* Validates that the specified amount is less than the limit.
* @param units the number of units to check
* @param limit the limit on the number of units
* @param unitName the unit name
*/
private void validate(long units, long limit, String unitName)
{
checkTrue(units <= limit,
"Invalid duration. The total number of %s must be less or equal to %s",
unitName,
Integer.MAX_VALUE);
}
/**
* Validates that the duration values are added in the proper order.
* @param unitIndex the unit index (e.g. years=1, months=2, ...)
*/
private void validateOrder(int unitIndex)
{
if (unitIndex == currentUnitIndex)
throw invalidRequest("Invalid duration. The %s are specified multiple times", getUnitName(unitIndex));
if (unitIndex <= currentUnitIndex)
throw invalidRequest("Invalid duration. The %s should be after %s",
getUnitName(currentUnitIndex),
getUnitName(unitIndex));
currentUnitIndex = unitIndex;
}
/**
* Returns the name of the unit corresponding to the specified index.
* @param unitIndex the unit index
* @return the name of the unit corresponding to the specified index.
*/
private String getUnitName(int unitIndex)
{
switch (unitIndex)
{
case 1: return "years";
case 2: return "months";
case 3: return "weeks";
case 4: return "days";
case 5: return "hours";
case 6: return "minutes";
case 7: return "seconds";
case 8: return "milliseconds";
case 9: return "microseconds";
case 10: return "nanoseconds";
default: throw new AssertionError("unknown unit index: " + unitIndex);
}
}
public Duration build()
{
return isNegative ? new Duration(-months, -days, -nanoseconds) : new Duration(months, days, nanoseconds);
}
}
}
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