com.discursive.jccook.collections.bag.BagExample.java Source code

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Here is the source code for com.discursive.jccook.collections.bag.BagExample.java

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/* 
 * ========================================================================
 * 
 * Copyright 2005 Tim O'Brien.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * ========================================================================
 */
package com.discursive.jccook.collections.bag;

import java.text.NumberFormat;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;

import org.apache.commons.collections.Bag;
import org.apache.commons.collections.bag.HashBag;
import org.apache.commons.lang.StringUtils;

public class BagExample {

    Bag inventoryBag = new HashBag();

    Album album1 = new Album("Radiohead", "OK Computer");
    Album album2 = new Album("Kraftwerk", "The Man-Machine");
    Album album3 = new Album("Charlie Parker", "Now's the Time");
    Album album4 = new Album("ABBA", "ABBA - Gold: Greatest Hits");

    public static void main(String[] args) {
        BagExample example = new BagExample();
        example.start();
    }

    private void start() {
        // Read our inventory into a Bag
        populateInventory();

        System.out.println("Inventory before Transactions");
        printAlbums(inventoryBag);
        printSeparator();

        // A Customer wants to purchase 400 copies of ABBA and 2 copies of Radiohead
        Bag shoppingCart1 = new HashBag();
        shoppingCart1.add(album4, 500);
        shoppingCart1.add(album3, 150);
        shoppingCart1.add(album1, 2);
        checkout(shoppingCart1, "Customer 1");

        // Another Customer wants to purchase 600 copies of ABBA 
        Bag shoppingCart2 = new HashBag();
        shoppingCart2.add(album4, 600);
        checkout(shoppingCart2, "Customer 2");

        // Another Customer wants to purchase 3 copies of Kraftwerk
        Bag shoppingCart3 = new HashBag();
        shoppingCart3.add(album2, 3);
        checkout(shoppingCart3, "Customer 3");

        System.out.println("Inventory after Transactions");
        printAlbums(inventoryBag);

    }

    private void populateInventory() {
        inventoryBag.add(album1, 200);
        inventoryBag.add(album2, 100);
        inventoryBag.add(album3, 500);
        inventoryBag.add(album4, 900);
    }

    private void printAlbums(Bag albumBag) {
        Set albums = albumBag.uniqueSet();
        Iterator albumIterator = albums.iterator();
        while (albumIterator.hasNext()) {
            Album album = (Album) albumIterator.next();
            NumberFormat format = NumberFormat.getInstance();
            format.setMinimumIntegerDigits(3);
            format.setMaximumFractionDigits(0);
            System.out.println("\t" + format.format(albumBag.getCount(album)) + " - " + album.getBand());
        }
    }

    private void checkout(Bag shoppingCart, String customer) {
        // Check to see if we have the inventory to cover this purchase
        if (inventoryBag.containsAll((Collection) shoppingCart)) {
            // Remove these items from our inventory
            inventoryBag.removeAll((Collection) shoppingCart);
            System.out.println(customer + " purchased the following items:");
            printAlbums(shoppingCart);
        } else {
            System.out.println(customer + ", I'm sorry but we are unable to fill your order.");
        }
        printSeparator();
    }

    private void printSeparator() {
        System.out.println(StringUtils.repeat("*", 65));
    }

}