org.opentripplanner.model.base.ValueObjectToStringBuilder Maven / Gradle / Ivy
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package org.opentripplanner.model.base;
import java.time.Duration;
import java.util.function.Function;
import org.opentripplanner.util.time.DurationUtils;
import org.opentripplanner.util.time.TimeUtils;
/**
* Use this to-string-builder to build value objects. A
* [ValueObject](http://wiki.c2.com/?ValueObject) is usually a small object/class with
* a few fields. We want the {@code toString()} to be small and easy to read. The
* text should be short and without class and field name prefixes.
*
* Examples:
*
* - Money: "5 kr", "USD 100"
* - Time: "2020-01-15", "3h3m5s", "14:23:59"
* - Coordinate: "(60.23451, 10.345678)"
*
*
* {@code ClassName{field1:value, field2:value, ..., NOT-SET:[fieldX, ...]}}
*
* Use the {@link #of()} factory method to create a instance of this class.
*/
public class ValueObjectToStringBuilder {
private static final String FIELD_SEPARATOR = " ";
private final StringBuilder sb = new StringBuilder();
private final OtpNumberFormat numFormat = new OtpNumberFormat();
boolean skipSep = true;
boolean skipNull = false;
/** Use factory method: {@link #of()}. */
private ValueObjectToStringBuilder() { }
/**
* Create a new toString builder for a [ValueObject](http://wiki.c2.com/?ValueObject) type.
* The builder will NOT include metadata(class and field names) when building the string.
*/
public static ValueObjectToStringBuilder of() {
return new ValueObjectToStringBuilder();
}
/* General purpose formatters */
/**
* {@code null} values are skipped after this method is called.
* This is the default behavior.
*/
public ValueObjectToStringBuilder skipNull() {
this.skipNull = true;
return this;
}
/**
* Use {@link #skipNull()} and {@code skipNull(false)} to turn the skip flag on and off.
* Example:
*
*
* ValueObjectToStringBuilder.of()
* .skipNull().addNum(null).addText("?")
* .includeNull().addNum(null).addText("!")
*
* is "?null!"
*
*/
public ValueObjectToStringBuilder includeNull() {
this.skipNull = false;
return this;
}
public ValueObjectToStringBuilder addNum(Number num) {
return addIt(num, numFormat::formatNumber);
}
public ValueObjectToStringBuilder addNum(Number num, String unit) {
return addIt(num, it -> numFormat.formatNumber(it, unit));
}
public ValueObjectToStringBuilder addBool(Boolean value, String ifTrue, String ifFalse) {
return addIt(value, it -> it ? ifTrue : ifFalse);
}
/** Add a quoted string value */
public ValueObjectToStringBuilder addStr(String value) {
return addIt(value, it -> "'" + it + "'");
}
/**
* Add plain text without quotes or any pending whitespace separator after it. Include
* white space if you need it.
*/
public ValueObjectToStringBuilder addText(String label) {
sb.append(label);
skipSep = true;
return this;
}
public ValueObjectToStringBuilder addEnum(Enum value) {
return addIt(value, Enum::name);
}
public ValueObjectToStringBuilder addObj(Object obj) {
return addIt(obj, Object::toString);
}
/* Special purpose formatters */
/**
* Add a Coordinate location: (longitude, latitude). The coordinate is
* printed with a precision of 5 digits after the period. The precision level used
* in OTP is 7 digits, so 2 coordinates that appear to be equal (by toString) might not be
* exactly equals.
*/
public ValueObjectToStringBuilder addCoordinate(Number lat, Number lon) {
if(skipNull && lat==null && lon==null) { return this; }
return addIt(
"(" + numFormat.formatCoordinate(lat) + ", "
+ numFormat.formatCoordinate(lon) + ")"
);
}
/**
* Add time in seconds since midnight. Format: HH:mm:ss.
*/
public ValueObjectToStringBuilder addServiceTime(int secondsPastMidnight) {
// Use a NOT_SET value which is unlikely to be used
return addServiceTime(secondsPastMidnight, -87_654_321);
}
/**
* Add time in seconds since midnight. Format: HH:mm:ss. Ignore if not set.
*/
public ValueObjectToStringBuilder addServiceTime(int secondsPastMidnight, int notSet) {
return addIt(TimeUtils.timeToStrCompact(secondsPastMidnight, notSet));
}
/**
* Add a duration to the string in format like '3h4m35s'. Each component (hours, minutes, and or
* seconds) is only added if they are not zero {@code 0}. This is the same format as the
* {@link Duration#toString()}, but without the 'PT' prefix.
*/
public ValueObjectToStringBuilder addDuration(Integer durationSeconds) {
return addIt(durationSeconds, DurationUtils::durationToStr);
}
/**
* Add a cost in the format $N.NN or $N (id decimals are zero)
*/
public ValueObjectToStringBuilder addCost(Integer cost) {
return addIt(cost, OtpNumberFormat::formatCost);
}
/**
* Add a cost in the format $N.NNu or $Nu, where 'N' is the number and 'u' is the unit.
*/
public ValueObjectToStringBuilder addCost(Integer cost, String unit) {
return addIt(cost, it -> OtpNumberFormat.formatCost(it, unit));
}
@Override
public String toString() {
return sb.toString();
}
/* private methods */
private ValueObjectToStringBuilder addIt(String value) {
return addIt(value, it -> it);
}
private ValueObjectToStringBuilder addIt(T value, Function mapToString) {
if(skipNull && value == null) { return this; }
if (skipSep) { skipSep = false; }
else { sb.append(FIELD_SEPARATOR); }
sb.append(value == null ? "null" : mapToString.apply(value));
return this;
}
}