Java Objects.requireNonNullElse方法代碼示例

import java.util.Objects; //導入方法依賴的package包/類
/**
 * Initializes a new charset with the given canonical name and alias
 * set.
 *
 * @param  canonicalName
 *         The canonical name of this charset
 *
 * @param  aliases
 *         An array of this charset's aliases, or null if it has no aliases
 *
 * @throws IllegalCharsetNameException
 *         If the canonical name or any of the aliases are illegal
 */
protected Charset(String canonicalName, String[] aliases) {
    String[] as = Objects.requireNonNullElse(aliases, zeroAliases);

    // Skip checks for the standard, built-in Charsets we always load
    // during initialization.
    if (canonicalName != "ISO-8859-1"
            && canonicalName != "US-ASCII"
            && canonicalName != "UTF-8") {
        checkName(canonicalName);
        for (int i = 0; i < as.length; i++) {
            checkName(as[i]);
        }
    }
    this.name = canonicalName;
    this.aliases = as;
}
 

import java.util.Objects; //導入方法依賴的package包/類
@Override
public String toString() {
    return "ReducedValue(" + field + "," + minWidth + "," + maxWidth +
            "," + Objects.requireNonNullElse(baseDate, baseValue) + ")";
}
 

import java.util.Objects; //導入方法依賴的package包/類
/**
 * Obtains an instance of {@code ZoneId} using its ID using a map
 * of aliases to supplement the standard zone IDs.
 * <p>
 * Many users of time-zones use short abbreviations, such as PST for
 * 'Pacific Standard Time' and PDT for 'Pacific Daylight Time'.
 * These abbreviations are not unique, and so cannot be used as IDs.
 * This method allows a map of string to time-zone to be setup and reused
 * within an application.
 *
 * @param zoneId  the time-zone ID, not null
 * @param aliasMap  a map of alias zone IDs (typically abbreviations) to real zone IDs, not null
 * @return the zone ID, not null
 * @throws DateTimeException if the zone ID has an invalid format
 * @throws ZoneRulesException if the zone ID is a region ID that cannot be found
 */
public static ZoneId of(String zoneId, Map<String, String> aliasMap) {
    Objects.requireNonNull(zoneId, "zoneId");
    Objects.requireNonNull(aliasMap, "aliasMap");
    String id = Objects.requireNonNullElse(aliasMap.get(zoneId), zoneId);
    return of(id);
}
 

import java.util.Objects; //導入方法依賴的package包/類
/**
 * Obtains an instance of {@code Chronology} from a temporal object.
 * <p>
 * This obtains a chronology based on the specified temporal.
 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
 * which this factory converts to an instance of {@code Chronology}.
 * <p>
 * The conversion will obtain the chronology using {@link TemporalQueries#chronology()}.
 * If the specified temporal object does not have a chronology, {@link IsoChronology} is returned.
 * <p>
 * This method matches the signature of the functional interface {@link TemporalQuery}
 * allowing it to be used as a query via method reference, {@code Chronology::from}.
 *
 * @param temporal  the temporal to convert, not null
 * @return the chronology, not null
 * @throws DateTimeException if unable to convert to a {@code Chronology}
 */
static Chronology from(TemporalAccessor temporal) {
    Objects.requireNonNull(temporal, "temporal");
    Chronology obj = temporal.query(TemporalQueries.chronology());
    return Objects.requireNonNullElse(obj, IsoChronology.INSTANCE);
}