我有一个 IndexEntry 的 ArrayList，它是一个简单的类，带有一个字符串、两个整数和一个compareTo()如下所示的方法。我的问题是，当我Collections.sort()大多数时候调用 ArrayList 时，一切都会正确排序，但有时永远不会比较两个元素，从而导致列表排序错误。
一些代码供参考：
//Get a list of the values
ArrayList<IndexEntry<T>> cleanEntries = new ArrayList<IndexEntry<T>>(matches.get(query).values());
//Sort Files/URLS
Collections.sort(cleanEntries);
public int compareTo(IndexEntry<T> other) {
if(this.occurrenceCount < other.getOccurrenceCount()){
return 1;
}
else if(this.occurrenceCount > other.getOccurrenceCount()){
return -1;
}
else{//Need to compare Initial Positions
if(this.firstOccurrence == other.getFirstOccurrence()){
return this.getLocationName().compareTo(other.getLocationName());
}
else if(this.firstOccurrence > other.getFirstOccurrence()){
return 1;
}
else{
return -1;
}
}
}
以下是字母“C”的所有 IndexEntry 的一些示例输出：
c
"index.html", 6, 2
"chickadee.html", 3, 2
"cuckoo.html", 3, 2
"crow.html", 3, 2
"crane.html", 3, 2
"cardinal.html", 3, 2
"quail.html", 2, 2
"robin.html", 2, 2
"finch.html", 2, 2
"kingfisher.html", 2, 2
"swan.html", 2, 2
"turkey.html", 2, 2
"ibis.html", 2, 2
"falcon.html", 2, 2
"albatross.html", 2, 2
"tern.html", 2, 2
"dove.html", 2, 2
"mockingbird.html", 2, 2
"owl.html", 2, 2
"sparrow.html", 2, 2
"hawk.html", 2, 2
"magpie.html", 2, 2
"nighthawk.html", 2, 2
"gull.html", 2, 2
"bluebird.html", 2, 2
"raven.html", 2, 2
"blackbird.html", 2, 2
"sandpiper.html", 2, 2
"pheasant.html", 2, 2
"roadrunner.html", 2, 2
"duck.html", 2, 2
"vulture.html", 2, 2
"pigeon.html", 2, 2
"heron.html", 2, 2
"stork.html", 2, 2
"warbler.html", 2, 2
"woodpecker.html", 2, 2
"hummingbird.html", 2, 2
"mallard.html", 2, 2
"osprey.html", 2, 2
"swallow.html", 2, 2
"wren.html", 2, 2
"goose.html", 2, 2
"meadowlark.html", 2, 2
"pelican.html", 2, 2
"starling.html", 2, 2
"loon.html", 2, 2
"eagle.html", 2, 2
"puffin.html", 2, 2
"egret.html", 2, 2
请注意，在确定出现次数和初始出现次数相同后，它会停止排序。正确的输出是：
c
"index.html", 6, 2
"cardinal.html", 3, 2
"chickadee.html", 3, 2
"crane.html", 3, 2
"crow.html", 3, 2
"cuckoo.html", 3, 2
"albatross.html", 2, 2
"blackbird.html", 2, 2
"bluebird.html", 2, 2
"dove.html", 2, 2
"duck.html", 2, 2
"eagle.html", 2, 2
"egret.html", 2, 2
"falcon.html", 2, 2
"finch.html", 2, 2
"goose.html", 2, 2
"gull.html", 2, 2
"hawk.html", 2, 2
"heron.html", 2, 2
"hummingbird.html", 2, 2
"ibis.html", 2, 2
"kingfisher.html", 2, 2
"loon.html", 2, 2
"magpie.html", 2, 2
"mallard.html", 2, 2
"meadowlark.html", 2, 2
"mockingbird.html", 2, 2
"nighthawk.html", 2, 2
"osprey.html", 2, 2
"owl.html", 2, 2
"pelican.html", 2, 2
"pheasant.html", 2, 2
"pigeon.html", 2, 2
"puffin.html", 2, 2
"quail.html", 2, 2
"raven.html", 2, 2
"roadrunner.html", 2, 2
"robin.html", 2, 2
"sandpiper.html", 2, 2
"sparrow.html", 2, 2
"starling.html", 2, 2
"stork.html", 2, 2
"swallow.html", 2, 2
"swan.html", 2, 2
"tern.html", 2, 2
"turkey.html", 2, 2
"vulture.html", 2, 2
"warbler.html", 2, 2
"woodpecker.html", 2, 2
"wren.html", 2, 2
无论如何，就像我说的那样，我必须省略很多信息，但如果有任何想法，我会非常感激。事实上，“匹配”数据结构在创建 ArrayList 后不会被修改。
编辑：嘿，我仍在阅读您的回复。非常感谢您的快速帮助！这是整个 IndexEntry 类，因为你们中的一些人问过：
class IndexEntry<extends Comparable<T>> implements Comparable<IndexEntry<T>>{
private T theLocation;
private Integer occurrenceCount;
private Integer firstOccurrence;
public IndexEntry(T location, Integer firstOcc, Integer occCount){
theLocation = location;
occurrenceCount = occCount;
firstOccurrence = firstOcc;
}
public int compareTo(IndexEntry<T> other) {
if(this.occurrenceCount < other.getOccurrenceCount()){
return 1;
}
else if(this.occurrenceCount > other.getOccurrenceCount()){
return -1;
}
else{//Need to compare Initial Positions
if(this.firstOccurrence == other.getFirstOccurrence()){
return this.getLocationName().compareTo(other.getLocationName());
}
else if(this.firstOccurrence > other.getFirstOccurrence()){
return 1;
}
else{
return -1;
}
}
}
public String getLocationName(){
if(theLocation instanceof File){
return ((File) theLocation).getAbsolutePath();
}
else{
return theLocation.toString();
}
}
public Integer getFirstOccurrence(){
return firstOccurrence;
}
public Integer getOccurrenceCount(){
return this.occurrenceCount;
}
public void addToOccurrenceCount(Integer toAdd){
occurrenceCount += toAdd;
}
public void setFirstOccurrence(Integer firstOcc){
firstOccurrence = new Integer(firstOcc);
}
}