转换实现 Comparator 和 Comparable to Scala 的 Java 类的简单惯用方法？

Question

我有一个现有的JFreeChart插件类，它不会转换为Scala v2.11，它比看起来更棘手。 Java是：

package x;
import org.apache.commons.lang.NotImplementedException;
import org.jfree.data.time.RegularTimePeriod;
import java.io.Serializable;
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
import java.util.Calendar;
import java.util.Comparator;
import java.util.Date;
public final class IntervalJFreeChart extends RegularTimePeriod implements  Comparator, Comparable, Serializable {
final int width;
final long seqNo;
final long firstMilli;
final long lastMilli;
public IntervalJFreeChart(Date time, int w) {
    MathContext mc = new MathContext(16, RoundingMode.FLOOR);
    width = w;
    BigDecimal wbd =  new java.math.BigDecimal(""+w);
    wbd.setScale(120, RoundingMode.FLOOR);
    BigDecimal bd = new java.math.BigDecimal(time.getTime());
    bd.setScale(120, RoundingMode.FLOOR);
    seqNo = bd.divide(wbd, mc).longValue();
    BigDecimal seqBd = new java.math.BigDecimal(seqNo);
    seqBd.setScale(120, RoundingMode.FLOOR);
    firstMilli = seqBd.multiply(wbd).longValue();
    lastMilli = firstMilli + w -1;
}
@Override
public IntervalJFreeChart previous() {
    return new IntervalJFreeChart(new Date(firstMilli - width), width); 
}
@Override
public IntervalJFreeChart next() {
    return new IntervalJFreeChart(new Date(lastMilli + width), width); 
}
@Override
public long getSerialIndex() {
    return this.seqNo;
}
@Override
public void peg(Calendar calendar) {
    throw new NotImplementedException("peg()");
}
@Override
public long getFirstMillisecond() {
    return firstMilli;
}
@Override
public long getFirstMillisecond(Calendar calendar) {
    calendar.setTimeInMillis(firstMilli);
    return firstMilli;
}
@Override
public long getLastMillisecond() {
    return lastMilli;
}
@Override
public long getLastMillisecond(Calendar calendar) {
    calendar.setTimeInMillis(lastMilli);
    return lastMilli;
}
@Override
public int compareTo(Object o) {
    return compare(this, o);
}
@Override
public int compare(Object o1, Object o2) {
    if (o2 instanceof IntervalJFreeChart) {
        final IntervalJFreeChart m1 = (IntervalJFreeChart)o1;
        final IntervalJFreeChart m2 = (IntervalJFreeChart)o2;
        final int diff = Long.valueOf(m1.seqNo).compareTo(m2.seqNo);
        if (diff > 0) return 1;
        if (diff < 0) return -1;
        return 0;
    }
    throw new RuntimeException("MilliInterval: compare error : "); 
}
}

我看到的问题是：抽象类 RegularTimePeriod 实现了 java 的 Comparable 接口，而没有为其指定类型参数。因此，Scala 实现需要两者：具体的比较器和可比的。

非常感谢建议。

Answer 1

由于类实际上只能与IntervalJFreeChart相比，只需使用 Comparable[IntervalJFreeChart] 即可。