www.pudn.com > chap8.rar > Mailbox.java

package chap8; 
 
import java.util.*; 
 
/** 
 * A mailbox consists of a collection of mail folders for a 
 * particular user. 
 */ 
public class Mailbox { 
    private String username; 
    private Map folders; 
 
    // a standard folder name 
    public static final String INBOX = "Inbox"; 
 
    /** 
     * @param username the owner of this mailbox. 
     * @param folders a Map that contains folder names as keys, 
     * and MailFolder objects as values. 
     */ 
    public Mailbox(String username, Map folders) { 
        this.username = username; 
        this.folders = folders; 
 
        if (!this.folders.containsKey(INBOX)) { 
            this.folders.put(INBOX, new ArrayList()); 
        } 
    } 
 
    /** 
     * @return the owner of this mailbox. 
     */ 
    public String getUsername() { 
        return this.username; 
    } 
 
    /** 
     * @return true if the specified folder is in this mailbox. 
     */ 
    public boolean containsFolder(String folderName) { 
        return this.folders.containsKey(folderName); 
    } 
 
    /** 
     * @return an Iterator of String folder names. 
     */ 
    public Iterator getFolderNames() { 
        return this.folders.keySet().iterator(); 
    } 
 
    /** 
     * @return a specific folder, or null if folderName is invalid. 
     */ 
    public MailFolder getFolder(String folderName) { 
        return (MailFolder) this.folders.get(folderName); 
    } 
}