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求助：java 语法问题

jayinseu

发贴: 3

于 2004-09-19 20:50

ShoppingCartItem scitem = (ShoppingCartItem) items.get(bookId);
(ShoppingCartItem) 是什么意思？编译总是通不过
。。。。。。。。。。。。。。。。。。。。。。。。。。。
package mypack;

import java.util.*;

public class ShoppingCart {
HashMap items = null;
int numberOfItems = 0;

public ShoppingCart() {
items = new HashMap();
}

public synchronized void add(String bookId, BookDetails book) {
if(items.containsKey(bookId)) {
ShoppingCartItem scitem = (ShoppingCartItem) items.get(bookId);
scitem.incrementQuantity();
} else {
ShoppingCartItem newItem = new ShoppingCartItem(book);
items.put(bookId, newItem);
}

numberOfItems++;
}

public synchronized void remove(String bookId) {
if(items.containsKey(bookId)) {
ShoppingCartItem scitem = (ShoppingCartItem) items.get(bookId);
scitem.decrementQuantity();

if(scitem.getQuantity() <= 0)
items.remove(bookId);

numberOfItems--;
}
}

public synchronized Collection getItems() {
return items.values();
}

protected void finalize() throws Throwable {
items.clear();
}

public synchronized int getNumberOfItems() {
return numberOfItems;
}
public synchronized double getTotal() {
double amount = 0.0;

for(Iterator i = getItems().iterator(); i.hasNext(); ) {
ShoppingCartItem item = (ShoppingCartItem) i.next();
BookDetails bookDetails = (BookDetails) item.getItem();

amount += item.getQuantity() * bookDetails.getPrice();
}
return roundOff(amount);
}

private double roundOff(double x) {
long val = Math.round(x*100); // cents
return val/100.0;
}

public synchronized void clear() {
items.clear();
numberOfItems = 0;
}
}

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人气	标题	作者	字数	发贴时间
1429	求助：java 语法问题	jayinseu	1822	2004-09-19 20:50
1137	Re:求助：java 语法问题	lfrick	42	2004-09-19 21:40
1069	Re:求助：java 语法问题	xiaoyu216	69	2004-09-24 14:24
1175	Re:求助：java 语法问题	scottding	100	2004-09-29 09:39

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