java TreeSet

import java.util.Comparator;
import java.util.Iterator;
import java.util.TreeSet;

public class TestArchiveMetaTreeSet {
  public static void main(String[] args) {
    Comparator<ArchiveMeta> comparator = new Comparator<ArchiveMeta>() {
      @Override
      public int compare(ArchiveMeta o1, ArchiveMeta o2) {
        return Long.compare(o1.getOffset(), o2.getOffset());
      }
    };
    TreeSet<ArchiveMeta> set = new TreeSet<>(comparator);

    ArchiveMeta entry1 = new ArchiveMeta(5, 1);
    set.add(entry1);
    ArchiveMeta entry2 = new ArchiveMeta(1, 3);
    set.add(entry2);
    set.add(new ArchiveMeta(3, 7));
    set.add(new ArchiveMeta(2, 4));
    Iterator<ArchiveMeta> iter = set.iterator();
    while (iter.hasNext()) {
      ArchiveMeta item = iter.next();
      System.out.println("offset: " + item.getOffset() + " id: " + item.getArchiveId());
    }
//    boolean res = set.remove(entry1);
    ArchiveMeta entry3 = new ArchiveMeta(10, 3); //因为定义了比较器，删除时只比较offset，不比较对象，所以这样也是成功的。
    boolean res = set.remove(entry3);
    System.out.println("res : " + res);
    iter = set.iterator();
    while (iter.hasNext()) {
      ArchiveMeta item = iter.next();
      System.out.println("offset: " + item.getOffset() + " id: " + item.getArchiveId());
    }

//    res = set.remove(entry2);
    ArchiveMeta entry4 = new ArchiveMeta(25, 1);
    res = set.remove(entry4);
    System.out.println("res : " + res);
    iter = set.iterator();
    while (iter.hasNext()) {
      ArchiveMeta item = iter.next();
      System.out.println("offset: " + item.getOffset() + " id: " + item.getArchiveId());
    }
  }
}

public class ArchiveMeta {
  public long archiveId;
  public long offset;

  public long getArchiveId() {
    return archiveId;
  }

  public long getOffset() {
    return offset;
  }

  public ArchiveMeta(long archiveId, long offset) {
    this.archiveId = archiveId;
    this.offset = offset;
  }
}