私は任務を与えました、そしてそれはそれ自体の最後の日です。ほとんどのことを行いましたが、最後の質問で、compareTo() 関数の作成に問題があります。
これが私たちに求めていることです。
比較する
public int compareTo(java.lang.Object other)
Specified by:
compareTo in interface java.lang.Comparable
これが私がしたことです
public int compareTo(Object obj)
{
Document tmp = (Document)obj;
if(this.text < tmp.text)
{
/* instance lt received */
return -1;
}
else if(this.text > tmp.text)
{
/* instance gt received */
return 1;
}
/* instance == received */
return 0;
}
ここに私のDocument.javaファイル全体があります
クラスドキュメント{プライベート文字列テキスト;
/**
* Default constructor; Initialize amount to zero.
*/
public Document()
{
text = "";
}
/**
* Default constructor; Initialize text to input value
* @param text New text value
*/
public Document(String text)
{
this.text = text;
}
/**
* Returns as a string the contents of the Document.
*/
public String toString()
{
return text;
}
ここにそれ自体のテストファイルがあります。
java.util.Arrays をインポートします。
public class Homework2 extends Document {
/** ======================
* ContainsKeyword
* Returns true if the Document
* object passed in contains keyword as a substring
* of its text property.
* ======================
*/
public static boolean ContainsKeyword(Document docObject, String keyword)
{
if (docObject.toString().indexOf(keyword,0) >= 0)
return true;
return false;
}
public static void main(String[] args){
Email email1= new Email("Programming in Java",
"Larry", "Curly", "Programming");
Email email2 = new Email("Running marathons",
"Speedy", "Gonzales", "races");
System.out.println(email1);
File file1 = new File("Some Java file", "file.txt");
File file2 = new File(
"Boluspor wins against Besiktas. Muahahahaha",
"bolutas.txt");
Document doc = new Document (
"ok?,ok?,ok?,ok?,ok?,ok?,ok?,ok?,ok?,ok?,ok?,ok?");
System.out.println("\n"+file1);
System.out.println("\nWhich contains Java?");
if (ContainsKeyword(email1,"Java")) System.out.println(" Email1");
if (ContainsKeyword(email2,"Java")) System.out.println(" Email2");
if (ContainsKeyword(file1,"Java")) System.out.println(" File1");
if (ContainsKeyword(file2,"Java")) System.out.println(" File2");
Document [] da = new Document [5];
da[0] = email1;
da[1] = email2;
da[2] = file1;
da[3] = file2;
da[4] = doc;
Arrays.sort(da);
System.out.println("\nAfter sort:");
for(Document d : da){
System.out.println(d);
}
}
}
私が聞きたかったのは、 Email.java と File.java のオブジェクトを比較できないことです。ドキュメント [] da で始まる最後の部分以外は何でもできます... その部分はエラーになります。ここで何が間違っていますか？
エラーは次のとおりです。
Exception in thread "main" java.lang.ClassCastException: Email cannot be cast to java.lang.Comparable
at java.util.Arrays.mergeSort(Arrays.java:1144)
at java.util.Arrays.sort(Arrays.java:1079)
at Homework2.main(Homework2.java:53)
アップロード **ここに私の電子メールとファイル クラスがあります..
/**
* First define class for Email, derive from Document
*/
class Email extends Document
{
private String sender;
private String recipient;
private String title;
private String body;
/**
* Constructors
*/
public Email()
{
super();
sender = "";
recipient = "";
title = "";
body = "";
}
public Email(String body, String sender, String recipient, String title)
{
this.sender = sender;
this.recipient = recipient;
this.title = title;
this.body = body;
}
// ======================
// Various accessor and mutator methods
// ======================
public String getSender()
{
return sender;
}
public void setSender(String sender)
{
this.sender = sender;
}
public String getRecipient()
{
return recipient;
}
public void setRecipient(String recipient)
{
this.recipient = recipient;
}
public String getTitle()
{
return title;
}
public void setTitle(String title)
{
this.title = title;
}
public String getBody(){
return body;
}
public void getBody(String body){
this.body = body;
}
/**
* Returns as a string the contents of the text fields concatenated
* together. Uses super.toString to get the parent's text.
*/
public String toString()
{
return "Sender:" + sender + ",Recipient:" + recipient + ",Title:" + title + ",Body:" + body + " " +
super.toString();
}
} // Email
とファイル。
/**
* Next define class for File, derive from Document
* For brevity, short one-line methods are defined here in the
* header.
*/
class File extends Document
{
private String pathname;
/**
* Constructors.
*/
public File()
{
super();
pathname = "";
}
public File(String body, String pathname)
{
super(body);
this.pathname = pathname;
}
// ======================
// Various accessor and mutator methods
// ======================
public void setPathname(String s)
{
pathname = s;
}
public String getPathname()
{
return pathname;
}
/**
* Returns as a string the contents of the text fields concatenated
* together. Uses super.toString to get the parent's text.
*/
public String toString()
{
return "Pathname " + pathname + " Body " + super.toString();
}
} // ファイル