/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.openjpa.trader.domain;
import java.io.Serializable;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import javax.persistence.MappedSuperclass;
import javax.persistence.OneToOne;
import javax.persistence.Version;
/**
* An abstract root for domain objects in OpenTrader designates a {@link Stock financial instrument}
* that can be traded. An abstract state of a tradable entity is immutable by the application.
*
* @author Pinaki Poddar
*
*/
@SuppressWarnings("serial")
@MappedSuperclass
public abstract class Tradable implements Serializable {
/**
* Primary identity of a traded entity.
* Its value is generated by the persistence provider.
* The application must not set or change this value.
* Hence no setter method is provided.
*/
@Id
@GeneratedValue
private Long id;
/**
* The price at which the underlying instrument be traded.
* Must always be positive.
*/
@Column(precision=10,scale=2)
private double price;
/**
* The volume or discreet number of underlying instrument be traded.
* Must always be positive.
*/
private int volume;
/**
* The underlying instrument.
* Must never be null.
*/
@ManyToOne(cascade={CascadeType.MERGE,CascadeType.DETACH,CascadeType.REFRESH},optional=false)
private Stock stock;
@OneToOne(cascade={CascadeType.MERGE,CascadeType.DETACH, CascadeType.REFRESH}, optional=true,
fetch=FetchType.LAZY)
private Trade trade;
/**
* A version identifier.
* Important (and almost mandatory) for any persistent entity to be part of
* simultaneous transaction. The persistence provider uses/updates the
* version to detect concurrent modification of an entity in simultaneous
* transaction.
*/
@Version
private int version;
/**
* A no-arg constructor to comply to both GWT compiler and OpenJPA
* bytecode enhancer.
*/
protected Tradable() {
}
/**
* Real constructor to be used by the concrete derivations.
*
* @param stock the underlying instrument. Must not be null.
* @param price the price. Must be positive.
* @param volume the volume. Must be positive.
*/
protected Tradable(Stock stock, double price, int volume) {
if (stock == null)
throw new IllegalArgumentException("Can not create Tradable with null stock");
if (price <= 0.0)
throw new IllegalArgumentException("Can not create Tradable with non-positive price " + price);
if (volume <= 0)
throw new IllegalArgumentException("Can not create Tradable with non-positive volume " + volume);
this.stock = stock;
this.price = price;
this.volume = volume;
}
/**
* Gets the identifier of this entity.
*
* @return identifier generated by the persistence provider.
*/
public long getId() {
return id;
}
/**
* Gets the underlying instrument.
*
* @return the underlying instrument. Never null.
*/
public Stock getStock() {
return stock;
}
/**
* Gets the price at which the underlying instrument be traded.
*
* @return the price of the underlying instrument for trading. Always greater than zero.
*/
public double getPrice() {
return price;
}
/**
* Gets the volume of the underlying instrument be traded.
*
* @return the volume of the underlying instrument for trading. Always greater than zero.
*/
public int getVolume() {
return volume;
}
public abstract double getGain();
/**
* Affirms if this offer has expired.
*/
public boolean isTraded() {
return trade != null;
}
public void updateStock(Stock updated) {
if (this.stock.equals(updated)) {
this.stock = updated;
} else {
throw new IllegalArgumentException(this + " can not change Stock from " + this.stock
+ " to " + updated);
}
}
public void setTrade(Trade t) {
if (trade != null)
throw new IllegalStateException(this + " has already been traded");
this.trade = t;
}
public Trade getTrade() {
return trade;
}
/**
* The version of the entity. Updated by the persistence provider.
*
* @return the current version of this entity.
*/
public int getVersion() {
return version;
}
/**
* It is important for persistence entity to overwrite the equals()
* method, preferably based only on its primary key attribute(s).
*/
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((id == null) ? 0 : id.hashCode());
return result;
}
/**
* It is important for persistence entity to overwrite the hashCode()
* method, preferably based only on its primary key attribute(s).
*/
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Tradable other = (Tradable) obj;
if (id == null) {
if (other.id != null)
return false;
} else if (!id.equals(other.id))
return false;
return true;
}
public String toString() {
String typeName = getClass().getName();
return typeName.substring(typeName.lastIndexOf('.')+1) + "-" + id;
}
}