转载须注明出处：

viewmode=contents，

Listing:挂牌。

比方某仅仅股票在某证券交易所挂牌交易。也就是上市交易。

老规矩，通过源代码学习：

package org.cryptocoinpartners.schema;import java.util.ArrayList;import java.util.List;import javax.persistence.Cacheable;import javax.persistence.Entity;import javax.persistence.Index;import javax.persistence.ManyToOne;import javax.persistence.NamedQueries;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;/** * Represents the possibility to trade one Asset for another */@SuppressWarnings("UnusedDeclaration")@Entity //在数据库创建Listing这个表@Cacheable//可缓存

//命名查询@NamedQueries({ @NamedQuery(name = "Listing.findByQuoteBase", query = "select a from Listing a where base=?1 and quote=?2 and prompt IS NULL"),        @NamedQuery(name = "Listing.findByQuoteBasePrompt", query = "select a from Listing a where base=?1 and quote=?2 and prompt=?3") })@Table(indexes = { @Index(columnList = "base"), @Index(columnList = "quote"), @Index(columnList = "prompt") })//@Table(name = "listing", uniqueConstraints = { @UniqueConstraint(columnNames = { "base", "quote", "prompt" }),//@UniqueConstraint(columnNames = { "base", "quote" }) })public class Listing extends EntityBase {

    protected Asset base;    protected Asset quote;    private Prompt prompt;

@ManyToOne(optional = false)    //@Column(unique = true)    public Asset getBase() {        return base;    }    @PostPersist    private void postPersist() {        //  PersistUtil.clear();        //  PersistUtil.refresh(this);        //PersistUtil.merge(this);        // PersistUtil.close();        //PersistUtil.evict(this);    }    @ManyToOne(optional = false)    //@Column(unique = true)    public Asset getQuote() {        return quote;    }    @ManyToOne(optional = true)    public Prompt getPrompt() {        return prompt;    }    /** will create the listing if it doesn't exist */    public static Listing forPair(Asset base, Asset quote) {        try {            Listing listing = PersistUtil.namedQueryZeroOne(Listing.class, "Listing.findByQuoteBase", base, quote);            if (listing == null) {                listing = new Listing(base, quote);                PersistUtil.insert(listing);            }            return listing;        } catch (NoResultException e) {            final Listing listing = new Listing(base, quote);            PersistUtil.insert(listing);            return listing;        }    }    public static Listing forPair(Asset base, Asset quote, Prompt prompt) {        try {            Listing listing = PersistUtil.namedQueryZeroOne(Listing.class, "Listing.findByQuoteBasePrompt", base, quote, prompt);            if (listing == null) {                listing = new Listing(base, quote, prompt);                PersistUtil.insert(listing);            }            return listing;        } catch (NoResultException e) {            final Listing listing = new Listing(base, quote, prompt);            PersistUtil.insert(listing);            return listing;        }    }    @Override    public String toString() {        return getSymbol();    }    @Transient    public String getSymbol() {        if (prompt != null)            return base.getSymbol() + '.' + quote.getSymbol() + '.' + prompt;        return base.getSymbol() + '.' + quote.getSymbol();    }    @Transient    protected double getMultiplier() {        if (prompt != null)            return prompt.getMultiplier();        return getContractSize() * getTickSize();    }    @Transient    protected double getTickValue() {        if (prompt != null)            return prompt.getTickValue();        return 1;    }    @Transient    protected double getContractSize() {        if (prompt != null)            return prompt.getContractSize();        return 1;    }    @Transient    protected double getTickSize() {        if (prompt != null)            return prompt.getTickSize();        return getPriceBasis();    }    @Transient    protected Amount getMultiplierAsAmount() {        return new DiscreteAmount((long) getMultiplier(), getVolumeBasis());    }    @Transient    protected double getVolumeBasis() {        double volumeBasis = 0;        if (prompt != null)            volumeBasis = prompt.getVolumeBasis();        return volumeBasis == 0 ? getBase().getBasis() : volumeBasis;    }    @Transient    public FeeMethod getMarginMethod() {        FeeMethod marginMethod = null;        if (prompt != null)            marginMethod = prompt.getMarginMethod();        return marginMethod == null ? null : marginMethod;    }    @Transient    public FeeMethod getMarginFeeMethod() {        FeeMethod marginFeeMethod = null;        if (prompt != null)            marginFeeMethod = prompt.getMarginFeeMethod();        return marginFeeMethod == null ? null : marginFeeMethod;    }    @Transient    protected double getPriceBasis() {        double priceBasis = 0;        if (prompt != null)            priceBasis = prompt.getPriceBasis();        return priceBasis == 0 ? getQuote().getBasis() : priceBasis;    }    @Transient    protected Asset getTradedCurrency() {        if (prompt != null && prompt.getTradedCurrency() != null)            return prompt.getTradedCurrency();        return getQuote();    }    @Transient    public FeeMethod getFeeMethod() {        if (prompt != null && prompt.getFeeMethod() != null)            return prompt.getFeeMethod();        return null;    }    @Transient    public double getFeeRate() {        if (prompt != null && prompt.getFeeRate() != 0)            return prompt.getFeeRate();        return 0;    }    @Transient    protected int getMargin() {        if (prompt != null && prompt.getMargin() != 0)            return prompt.getMargin();        return 0;    }    public static List
     
       allSymbols() {        List
      
        result = new ArrayList<>();        List
       
         listings = PersistUtil.queryList(Listing.class, "select x from Listing x");        for (Listing listing : listings)            result.add((listing.getSymbol()));        return result;    }    // JPA    protected Listing() {    }    protected void setBase(Asset base) {        this.base = base;    }    protected void setQuote(Asset quote) {        this.quote = quote;    }    protected void setPrompt(Prompt prompt) {        this.prompt = prompt;    }    public Listing(Asset base, Asset quote) {        this.base = base;        this.quote = quote;    }    public Listing(Asset base, Asset quote, Prompt prompt) {        this.base = base;        this.quote = quote;        this.prompt = prompt;    }    public static Listing forSymbol(String symbol) {        symbol = symbol.toUpperCase();        final int dot = symbol.indexOf('.');        if (dot == -1)            throw new IllegalArgumentException("Invalid Listing symbol: \"" + symbol + "\"");        final String baseSymbol = symbol.substring(0, dot);        Asset base = Asset.forSymbol(baseSymbol);        if (base == null)            throw new IllegalArgumentException("Invalid base symbol: \"" + baseSymbol + "\"");        int len = symbol.substring(dot + 1, symbol.length()).indexOf('.');        len = (len != -1) ? Math.min(symbol.length(), dot + 1 + symbol.substring(dot + 1, symbol.length()).indexOf('.')) : symbol.length();        final String quoteSymbol = symbol.substring(dot + 1, len);        final String promptSymbol = (symbol.length() > len) ? symbol.substring(len + 1, symbol.length()) : null;        Asset quote = Asset.forSymbol(quoteSymbol);        if (quote == null)            throw new IllegalArgumentException("Invalid quote symbol: \"" + quoteSymbol + "\"");        if (promptSymbol == null)            return Listing.forPair(base, quote);        Prompt prompt = Prompt.forSymbol(promptSymbol);        return Listing.forPair(base, quote, prompt);    }    @Override    public boolean equals(Object obj) {        if (obj instanceof Listing) {            Listing listing = (Listing) obj;            if (!listing.getBase().equals(getBase())) {                return false;            }            if (!listing.getQuote().equals(getQuote())) {                return false;            }            if (listing.getPrompt() != null)                if (this.getPrompt() != null) {                    if (!listing.getPrompt().equals(getPrompt()))                        return false;                } else {                    return false;                }            return true;        }        return false;    }    @Override    public int hashCode() {        return getPrompt() != null ? getQuote().hashCode() + getBase().hashCode() + getPrompt().hashCode() : getQuote().hashCode() + getBase().hashCode();    }}
       
      
     

protected Asset base;    protected Asset quote;    private Prompt prompt;