转载需注明出处：http://blog.csdn.net/minimicall，http://cloudtrade.top/
前面一节我们说到了远端事件。其中，市场数据就属于远端事件。市场数据有什么？我们通过代码来回答这个问题：
package org.cryptocoinpartners.schema;
import javax.annotation.Nullable;
import javax.persistence.Entity;
import javax.persistence.ManyToOne;
import org.joda.time.Instant;
/**
* @author Tim Olson
*/
@Entity //实体，在数据库中会创建表格
public abstract class MarketData extends RemoteEvent {
protected MarketData(Instant time, @Nullable String remoteKey, Market market) {
this(time, Instant.now(), remoteKey, market);
}
protected MarketData(Instant time, Instant timeReceived, String remoteKey, Market market) {
super(time, timeReceived, remoteKey);
this.market = market;
}
@ManyToOne(optional = false)
public Market getMarket() {
return market;
}
// JPA
protected MarketData() {
super();
}
protected void setMarket(Market market) {
this.market = market;
}
private Market market;//市场
}
市场数据里面只有一个成员，市场。也即是说市场数据是某一时刻的市场。
我们接下来看看市场又有什么数据，Market。
我们通过注释代码来学习。
package org.cryptocoinpartners.schema;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import javax.persistence.Basic;
import javax.persistence.Cacheable;
import javax.persistence.Entity;
import javax.persistence.Index;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQuery;
import javax.persistence.NoResultException;
import javax.persistence.PostPersist;
import javax.persistence.Table;
import javax.persistence.Transient;
import org.cryptocoinpartners.enumeration.FeeMethod;
import org.cryptocoinpartners.util.PersistUtil;
import org.cryptocoinpartners.util.RemainderHandler;
/**
* Represents the possibility to trade one Asset for another at a specific Exchange.
*
* @author Tim Olson
*/
@Entity //表格
@Cacheable // 缓存
@NamedQuery(name = "Market.findByMarket", query = "select m from Market m where exchange=?1 and listing=?2") // 命名查询
@Table(indexes = { @Index(columnList = "exchange"), @Index(columnList = "listing"), @Index(columnList = "active") }) //编织索引
public class Market extends EntityBase {
public static Collection<Market> findAll() {//查询所有市场数据
return PersistUtil.queryList(Market.class, "select m from Market m");
}
/** adds the Market to the database if it does not already exist */
public static Market findOrCreate(Exchange exchange, Listing listing) {
return findOrCreate(exchange, listing, listing.getPriceBasis(), listing.getVolumeBasis());
}
@PostPersist
private void postPersist() {
//PersistUtil.detach(this);
}
//查询或创建市场数据
public static Market findOrCreate(Exchange exchange, Listing listing, double quoteBasis, double volumeBasis) {
// final String queryStr = "select m from Market m where exchange=?1 and listing=?2";
try {
return PersistUtil.namedQueryOne(Market.class, "Market.findByMarket", exchange, listing);
} catch (NoResultException e) {
final Market ml = new Market(exchange, listing, quoteBasis, volumeBasis);
PersistUtil.insert(ml);
return ml;
}
}
/**
@return active Markets for the given exchange
*/
public static Collection<Market> find(Exchange exchange) {
return PersistUtil.queryList(Market.class, "select s from Market s where exchange=?1 and active=?2", exchange, true);
}
/**
@return active Markets for the given listing
*/
public static Collection<Market> find(Listing listing) {
return PersistUtil.queryList(Market.class, "select s from Market s where listing=?1 and active=?2", listing, true);
}
@ManyToOne(optional = false)
public Exchange getExchange() {
return exchange;
}
@ManyToOne(optional = false)
public Listing getListing() {
return listing;
}
@Basic(optional = false)
public double getPriceBasis() {
return listing.getPriceBasis() == 0 ? priceBasis : listing.getPriceBasis();
}
@Transient
public int getScale() {
int length = (int) (Math.log10(getPriceBasis()));
return length;
}
@Basic(optional = false)
public double getVolumeBasis() {
return listing.getVolumeBasis() == 0 ? volumeBasis : listing.getVolumeBasis();
}
/** @return true iff the Listing is currently traded at the Exchange. The Market could have been retired. */
public boolean isActive() {
return active;
}
@Transient
public Asset getBase() {
return listing.getBase();
}
@Transient
public Asset getQuote() {
return listing.getQuote();
}
@Transient
public int getMargin() {
return listing.getMargin() == 0 ? exchange.getMargin() : listing.getMargin();
}
@Transient
public double getFeeRate() {
return listing.getFeeRate() == 0 ? exchange.getFeeRate() : listing.getFeeRate();
}
@Transient
public FeeMethod getMarginFeeMethod() {
return listing.getMarginFeeMethod() == null ? exchange.getMarginFeeMethod() : listing.getMarginFeeMethod();
}
@Transient
public FeeMethod getFeeMethod() {
return listing.getFeeMethod() == null ? exchange.getFeeMethod() : listing.getFeeMethod();
}
@Transient
public double getMultiplier() {
return listing.getMultiplier();
}
@Transient
public double getTickValue() {
return listing.getTickValue();
}
@Transient
public double getContractSize() {
return listing.getContractSize();
}
@Transient
public double getTickSize() {
return listing.getTickSize();
}
@Transient
public Asset getTradedCurrency() {
return listing.getTradedCurrency();
}
@Transient
public String getSymbol() {
return exchange.toString() + ':' + listing.toString();
}
@Override
public String toString() {
return getSymbol();
}
public static Market forSymbol(String marketSymbol) {
for (Market market : findAll()) {
if (market.getSymbol().equalsIgnoreCase(marketSymbol))
return market;
}
return null;
}
public static List<String> allSymbols() {
List<String> result = new ArrayList<>();
List<Market> markets = PersistUtil.queryList(Market.class, "select m from Market m");
for (Market market : markets)
result.add((market.getSymbol()));
return result;
}
public static class MarketAmountBuilder {
public DiscreteAmount fromPriceCount(long count) {
return priceBuilder.fromCount(count);
}
public DiscreteAmount fromVolumeCount(long count) {
return volumeBuilder.fromCount(count);
}
public DiscreteAmount fromPrice(BigDecimal amount, RemainderHandler remainderHandler) {
return priceBuilder.fromValue(amount, remainderHandler);
}
public DiscreteAmount fromVolume(BigDecimal amount, RemainderHandler remainderHandler) {
return volumeBuilder.fromValue(amount, remainderHandler);
}
public MarketAmountBuilder(double priceBasis, double volumeBasis) {
this.priceBuilder = DiscreteAmount.withBasis(priceBasis);
this.volumeBuilder = DiscreteAmount.withBasis(volumeBasis);
}
private final DiscreteAmount.DiscreteAmountBuilder priceBuilder;
private final DiscreteAmount.DiscreteAmountBuilder volumeBuilder;
}
public MarketAmountBuilder buildAmount() {
if (marketAmountBuilder == null)
marketAmountBuilder = new MarketAmountBuilder(getPriceBasis(), getVolumeBasis());
return marketAmountBuilder;
}
// JPA
protected Market() {
}
protected void setExchange(Exchange exchange) {
this.exchange = exchange;
}
protected void setListing(Listing listing) {
this.listing = listing;
}
protected void setActive(boolean active) {
this.active = active;
}
protected void setPriceBasis(double quoteBasis) {
this.priceBasis = quoteBasis;
}
protected void setVolumeBasis(double volumeBasis) {
this.volumeBasis = volumeBasis;
}
private Market(Exchange exchange, Listing listing, double priceBasis, double volumeBasis) {
this.exchange = exchange;
this.listing = listing;
this.priceBasis = priceBasis;
this.volumeBasis = volumeBasis;
this.active = true;
}
private Exchange exchange;//交易所
private Listing listing;//挂牌清单
private double priceBasis;//基准价格
private double volumeBasis;//基准量
private boolean active;//是否活跃
private MarketAmountBuilder marketAmountBuilder;
}
