CashBalance.java

package sample.model.asset;

import java.math.*;
import java.time.*;
import java.util.Optional;

import javax.persistence.*;

import lombok.*;
import sample.context.orm.*;
import sample.model.constraints.*;
import sample.util.*;

/**
 * 口座残高を表現します。
 */
@Entity
@Data
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(callSuper = false)
public class CashBalance extends OrmActiveRecord<CashBalance> {
    private static final long serialVersionUID = 1L;

    /** ID */
    @Id
    @GeneratedValue
    private Long id;
    /** 口座ID */
    @IdStr
    private String accountId;
    /** 基準日 */
    @ISODate
    private LocalDate baseDay;
    /** 通貨 */
    @Currency
    private String currency;
    /** 金額 */
    @Amount
    private BigDecimal amount;
    /** 更新日 */
    @ISODateTime
    private LocalDateTime updateDate;

    /**
     * 残高へ指定した金額を反映します。
     * low ここではCurrencyを使っていますが、実際の通貨桁数や端数処理定義はDBや設定ファイル等で管理されます。
     */
    public CashBalance add(final OrmRepository rep, BigDecimal addAmount) {
        int scale = java.util.Currency.getInstance(currency).getDefaultFractionDigits();
        RoundingMode mode = RoundingMode.DOWN;
        setAmount(Calculator.of(amount).scale(scale, mode).add(addAmount).decimal());
        return update(rep);
    }

    /**
     * 指定口座の残高を取得します。(存在しない時は繰越保存後に取得します)
     * low: 複数通貨の適切な考慮や細かい審査は本筋でないので割愛。
     */
    public static CashBalance getOrNew(final OrmRepository rep, String accountId, String currency) {
        LocalDate baseDay = rep.dh().time().day();
        Optional<CashBalance> m = rep.tmpl().get(
                "from CashBalance c where c.accountId=?1 and c.currency=?2 and c.baseDay=?3 order by c.baseDay desc",
                accountId, currency, baseDay);
        return m.orElseGet(() -> create(rep, accountId, currency));
    }

    private static CashBalance create(final OrmRepository rep, String accountId, String currency) {
        TimePoint now = rep.dh().time().tp();
        Optional<CashBalance> m = rep.tmpl().get(
                "from CashBalance c where c.accountId=?1 and c.currency=?2 order by c.baseDay desc", accountId,
                currency);
        if (m.isPresent()) { // 残高繰越
            CashBalance prev = m.get();
            return new CashBalance(null, accountId, now.getDay(), currency, prev.getAmount(), now.getDate()).save(rep);
        } else {
            return new CashBalance(null, accountId, now.getDay(), currency, BigDecimal.ZERO, now.getDate()).save(rep);
        }
    }

}