cn.bjfu.springdao.jpa.domain.order.LineItem.java Source code

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Here is the source code for cn.bjfu.springdao.jpa.domain.order.LineItem.java

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/*
 * Copyright 2012 the original author or authors.
 *
 * 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 cn.bjfu.springdao.jpa.domain.order;

import java.math.BigDecimal;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.ManyToOne;

import org.springframework.util.Assert;

import cn.bjfu.springdao.jpa.domain.AbstractEntity;
import cn.bjfu.springdao.jpa.domain.Product;

/**
 * A line item.
 * 
 * @author Oliver Gierke
 */
@Entity
public class LineItem extends AbstractEntity {

    @ManyToOne
    private Product product;

    @Column(nullable = false)
    private BigDecimal price;
    private int amount;

    /**
     * Creates a new {@link LineItem} for the given {@link Product}.
     * 
     * @param product must not be {@literal null}.
     */
    public LineItem(Product product) {
        this(product, 1);
    }

    /**
     * Creates a new {@link LineItem} for the given {@link Product} and amount.
     * 
     * @param product must not be {@literal null}.
     * @param amount
     */
    public LineItem(Product product, int amount) {

        Assert.notNull(product, "The given Product must not be null!");
        Assert.isTrue(amount > 0, "The amount of Products to be bought must be greater than 0!");

        this.product = product;
        this.amount = amount;
        this.price = product.getPrice();
    }

    public LineItem() {

    }

    /**
     * Returns the {@link Product} the {@link LineItem} refers to.
     * 
     * @return
     */
    public Product getProduct() {
        return product;
    }

    /**
     * Returns the amount of {@link Product}s to be ordered.
     * 
     * @return
     */
    public int getAmount() {
        return amount;
    }

    /**
     * Returns the price a single unit of the {@link LineItem}'s product.
     * 
     * @return the price
     */
    public BigDecimal getUnitPrice() {
        return price;
    }

    /**
     * Returns the total for the {@link LineItem}.
     * 
     * @return
     */
    public BigDecimal getTotal() {
        return price.multiply(BigDecimal.valueOf(amount));
    }
}