我有一个有趣的问题。
我已经创建了一个界面；这个想法是实现这个接口的类也必须实现 TimeRangeBuilder
import java.util.Date;
public interface TimeRange<T> extends Comparable<T> {
public static interface TimeRangeBuilder<T> {
public TimeRangeBuilder<T> startDate(Date startDate);
public TimeRangeBuilder<T> endDate(Date endDate);
public T build();
}
public Date getStartDate();
public Date getEndDate();
}
但不幸的是，这不是它的工作方式。当我在一个具体的类中实现这个接口时；TimeRangeBuilder 的实现是完全可选的。
为了让您了解我的前进方向，这是我的实现类
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import ru.crystals.videoutil.utils.TimeRange;
public class VidArchive implements TimeRange<VidArchive> {
/** date format used to convert Date objects to human-readable form for the toString() function */
private static final DateFormat DATE_FORMAT = new SimpleDateFormat("HH:mm:ss");
private final byte[] bytes;
private final String cam;
private final Date startDate;
private final Date endDate;
private final String fileName;
private final String directory;
public static class Builder implements TimeRangeBuilder<VidArchive> {
private byte[] bytes;
private String cam;
private Date startDate;
private Date endDate;
private String fileName;
private String directory;
public Builder() {}
public Builder bytes(byte[] bytes) { this.bytes = bytes; return this; }
public Builder cam(String cam) { this.cam = cam; return this; }
@Override
public Builder startDate(Date startDate) { this.startDate = startDate; return this; }
@Override
public Builder endDate(Date endDate) { this.endDate = endDate; return this; }
public Builder fileName(String fileName) { this.fileName = fileName; return this; }
public Builder directory(String directory) { this.directory = directory; return this; }
@Override
public VidArchive build() { return new VidArchive(this); }
}
private VidArchive(Builder builder) {
bytes = builder.bytes;
cam = builder.cam;
startDate = builder.startDate;
endDate = builder.endDate;
fileName = builder.fileName;
directory = builder.directory;
}
public byte[] getBytes() { return bytes; }
public String getCam() { return cam; }
@Override
public Date getStartDate() { return startDate; }
@Override
public Date getEndDate() { return endDate; }
public String getFileName() { return fileName; }
public String getDirectory() { return directory; }
@Override
public int compareTo(VidArchive vidArchive) {
return startDate.compareTo(vidArchive.getStartDate());
}
@Override
public String toString() {
return DATE_FORMAT.format(startDate) + " - " + DATE_FORMAT.format(endDate);
}
}
这一切都归结为这一点；我有另一个类不仅应该与 VidArchive 类兼容，而且应该与 TimeRange 接口的所有实现兼容。这是我想要工作的代码
public class TimeBar<E extends TimeRange<E>> extends JProgressBar {
private TreeSet<E> timeRanges;
...
...
public void seekToTime() {
/** create a dummy object (an implementation of the TimeRange interface) with the most recent date set in TimeBarUI, so that it can be compared
* to all the other objects in the set in order to find the closest one by time*/
E archive = new E.Builder().
startDate(((TimeBarUI)ui).getMostRecentDate()).
endDate(((TimeBarUI)ui).getMostRecentDate()).
build();
TimeRange<E> closest = timeRanges.headSet(archive, true).last();
...
}
}
各位先生可以想象；整件事E.Builder()..是的，它不起作用。帮助我让它工作，或者为我的难题找到一个替代解决方案（我愿意接受替代的 Builder 实现，但我非常想保留我的 Builder.
PS也欢迎有关我的代码的任何其他建议。我总是渴望改进。