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我一直在试图制作一些方法，它们将通过至少4种不同方式对链接列表进行排序。不过，我不断收到编译器错误Java - 尝试使用自定义比较器对LinkedList进行排序，无法找到符号类型
MyBikeList.java:80: cannot find symbol
symbol : method sort(java.util.List<Bike>,Comparator<Bike>)
location: class java.util.Collections
Collections.sort(bikeInventory, byYear);
我的代码如下（这不是完整的）
public class MyBikeList implements BikeList
{
List<Bike> bikeInventory = new LinkedList();
public static Comparator<Bike> byPrice = new PriceComparator();
public static Comparator<Bike> byYear = new YearComparator();
public static Comparator<Bike> byModel = new ModelComparator();
public static Comparator<Bike> byReg = new RegComparator();
public boolean add(Bike bike)
{
{
}
public boolean remove(Bike bike)
{
}
public Bike find(String regNo)
{
ListNode itr = header.next;
while(itr != null && !itr.element.equals(Bike.bikeRegNO))
{
itr = itr.next;
}
return new LinkedListIterator(itr);
}
public int sortByRegNo()
{
Collections.sort(bikeInventory, byReg);
return byReg.getCount();
}
public int sortByPrice()
{
Collections.sort(bikeInventory, byPrice);
return byPrice.getCount();
}
public int sortByModel()
{
Collections.sort(bikeInventory, byModel);
return byModel.getCount();
}
public int sortByYear()
{
Collections.sort(bikeInventory, byYear);
return byYear.getCount();
}
public void clear()
{
bikeInventory.clear();
}
public int size()
{
int s = bikeInventory.size();
return s;
}
}
import java.util.*;
public interface Comparator<T>
{
int compare(T o1, T o2);
int getCount();
}
import java.util.*;
public class PriceComparator implements Comparator<Bike>
{
private int count;
public int compare(Bike b1, Bike b2)
{
int b1Pr = b1.getPrice();
int b2Pr = b2.getPrice();
if(b1Pr > b2Pr)
{
count++;
return 1;
}
if(b1Pr == b2Pr)
{
return 0;
}
return -1;
}
public int getCount()
{
return count;
}
}
import java.util.*;
public class YearComparator implements Comparator<Bike>
{
private int count = 0;
public int compare(Bike b1, Bike b2)
{
int b1Yr = b1.getYear();
int b2Yr = b2.getYear();
if(b1Yr > b2Yr)
{
count++;
return 1;
}
else
if(b1Yr == b2Yr)
{
return 0;
}
return -1;
}
public int getCount()
{
return count;
}
}
import java.util.*;
public class RegComparator implements Comparator<Bike>
{
private int count;
public int compare(Bike b1, Bike b2)
{
String b1Reg = b1.getRegNo();
String b2Reg = b2.getRegNo();
int result = b1Reg.compareTo(b2Reg);
if(result > 0)
{
count++;
return 1;
}
if(result == 0)
{
return 0;
}
return -1;
}
public int getCount()
{
return count;
}
}
import java.util.*;
public class ModelComparator implements Comparator<Bike>
{
private int count;
public int compare(Bike b1, Bike b2)
{
String b1Model = b1.getModel();
String b2Model = b2.getModel();
int result = b1Model.compareTo(b2Model);
if(result > 0)
{
count++;
return 1;
}
if(result == 0)
{
return 0;
}
return -1;
}
public int getCount()
{
return count;
}
}
public class MyBike implements Bike
{
private String bikeModel;
private String bikeRegNo;
private String bikeYear;
private String bikePrice;
private int counter;
public MyBike (String model, String regNo, String year, String price)
{
bikeModel = model;
bikeRegNo = regNo;
bikeYear = year;
bikePrice = price;
counter = 0;
}
public String getModel()
{
return bikeModel;
}
public String getRegNo()
{
return bikeRegNo;
}
public int getYear()
{
int aYear = toInt(bikeYear);
return aYear;
}
public int getPrice()
{
int aPrice = toInt(bikePrice);
return aPrice;
}
public void setPrice(int newPrice)
{
bikePrice = "" + newPrice;
}
public int getCompCount()
{
int tempInt = counter;
counter = 0;
return tempInt;
}
public boolean match(String model, int year, int price)
{
boolean nearMatch = false;
int pricePercent = getPrice() /10;
if(model != null)
{
nearMatch = true;
}
if((year > 0) && (year >= getYear() -1) && (year <= getYear() + 1))
{
nearMatch = true;
}
if((price > 0) && (price >= getPrice() - pricePercent) && (price <= getPrice() + pricePercent))
{
nearMatch = true;
}
if(nearMatch == true)
{
counter++;
}
return nearMatch;
}
public String toString()
{
String aString = ("" + getPrice() + " " + getYear()
+ " " + getRegNo() + " " +
getModel());
return aString;
}
public int toInt(String s)
{
int anInt = Integer.parseInt(s);
return anInt;
}
public int compareTo(Bike b)
{
int result = getRegNo().compareTo(b.getRegNo());
if (result < 0)
{
return -1;
}
if (result == 0)
{
return 0;
}
return 1;
}
public void compare(Bike b)
{
}
}
public interface Bike extends Comparable<Bike>
{
/**
* Get the bike's model description
* @return the model
*/
public String getModel();
/**
* Get the bike's registration number
* @return the regNo
*/
public String getRegNo();
/**
* Get the bike's year of registration
* @return the year
*/
public int getYear();
/**
* Get the bike's price
* @return the price
*/
public int getPrice();
/**
* Set the bike's price
* @param price the price
*/
public void setPrice(int price);
/**
* Get & reset the comparison counter value
* @return the count (before resetting to zero)
*/
public int getCompCount();
/**
* Check for "near match" (see assignment brief for details)
* @param model ignore if null/empty, else match as substring,
* if substring is engine size e.g. "800cc", remove number substring
* and convert to a number and match to within 50
* @param year ignore if <= 0, else match to within 1 yr
* @param price ignore if <= 0, else match to within 10%
* @return true if "near match" as above, else false
*/
public boolean match(String model, int year, int price);
/**
* Create a string with price, year, regNo & model description
* concatenated in that order, separated by single tabs
* @return a printable string as above
*/
public String toString();
}
public interface BikeList
{
/**
* Add a given bike object to the list
* @param bike the bike object to add
* @return true if successful, else false
*/
public boolean add(Bike bike);
/**
* Remove a bike object from the list
* @param bike the bike object to remove
* @return true if successful, else false
*/
public boolean remove(Bike bike);
/**
* Find a bike given its registration number
* @param regNo the registration number
* @return the bike object, or null if not found
*/
public Bike find(String regNo);
/**
* Sort by registration number
* @return the number of comparisons
*/
public int sortByRegNo();
/**
* Sort by registration year
* @return the number of comparisons
*/
public int sortByYear();
/**
* Sort by price
* @return the number of comparisons
*/
public int sortByPrice();
/**
* Sort by model description
* @return the number of comparisons
*/
public int sortByModel();
/**
* Clear the list
*/
public void clear();
/**
* Get the size of the list (= number of bikes)
* @return the list size
*/
public int size();
/**
* Convert list to single string with \n after each record
* @return the string as above
*/
public String toString();
/**
* Get an iterator object to traverse the bike list
* @return a java.util.Iterator<Bike> object
*/
public java.util.Iterator<Bike> iterator();
}
预先感谢您，遗憾的长度，我不知道有多少是重要的。
谢谢！
你为什么要重新定义Comparator接口？ – 2011-03-28 01:11:08