DRecordInstance.java :  » Database-ORM » SimpleORM » simpleorm » data » Java Open Source

package simpleorm.data;

import org.apache.commons.beanutils.PropertyUtils;

import java.util.Collections;

/**
 * A real instance of a record, eg. an Employee or a Department.
 * Normally specialized for the actual record, eg. Emp extends DRecordInstance.<p>
 *
 * This delegates the actual storage of the record's field to a Commons-beanutils bean.
 * If needed, users can specialize with dyna beans.
 * (Not as elegant as our own hashMap of DFieldInstances, for old values etc., but simpler
 * given main implementation will be simple beans or ddlutils.)
 */
public class DRecordInstance {

     final DRecordMeta recordMeta;

    Object bean; // that stores the acual values.

    public DRecordInstance(DRecordMeta meta) { // SORM no param so can be newInstanced
        this.recordMeta = meta;
    }

    /**
     * Get value as its base object, without any conversion, from the Bean.
     * 
     */
    public Object getObject(DFieldMeta meta) {
        return getObject(meta.getName());
    }


    public Object getObject(String property) {
        try {
            return PropertyUtils.getSimpleProperty(bean, property);
        } catch (Exception ex) {
            throw new DException("Could not access prop " + property, ex);
        }
    }
    public void setObject(DFieldMeta meta, Object value) {
       setObject(meta.name, value);
    }
    public void setObject(String property, Object value) {
        try {
          PropertyUtils.setSimpleProperty(bean, property, value);
        } catch (Exception ex) {
            throw new DException("While " + this + "." + property + " = " + value, ex);
        }
    }
    /** just GetObject.toString */
    public String getString(DFieldMeta meta) {
        Object res = getObject(meta);
        return res == null ? null : res.toString();
    }

    /** Compares primary keys only. */
    public boolean equals(Object other) {
        DRecordInstance otherRec = (DRecordInstance)other;
        for ( DFieldMeta field: recordMeta.getFields() )
            if ( field.isPrimaryKey() ) {
                Object val1 = getObject(field);
                if ( val1 == null )
                    throw new DException("Null Primary Key " + this);
                Object val2 = otherRec.getObject(field);
                if ( ! val1.equals(val2) ) return false;
            }
        return true;
    }

    /** Of the primary keys only. */
    public int hashCode() {
        int hash = 0;
        for ( DFieldMeta field: recordMeta.getFields() ) {
            if ( field.isPrimaryKey() ) {
                Object val1 = getObject(field);
                if ( val1 == null )
                    throw new DException("Null Primary Key " + this);
                hash = (hash<<13) + hash + val1.hashCode(); // Java doesn;t detect int overflow.
            }
        }
        return hash;
    }

    /** Hack, and badly implemented (key could contain "~").  */
    public String hackPrimaryKeyString() {
        String pkey="";
        for ( DFieldMeta field: recordMeta.getFields() )
            if ( field.isPrimaryKey() )
                pkey += getObject(field) + "~"; // hack
        return pkey;
    }

    public String toString(){
        StringBuilder buf = new StringBuilder("{"+ recordMeta.getTableName() + " ");
        for ( DFieldMeta field: recordMeta.getFields() )
            if ( field.isPrimaryKey() ) {
                buf.append(getObject(field)+"");
                buf.append(", ");
            }
        buf.append("}");
        return buf.toString();
    }

    public String toLongString() {
        try {
        StringBuilder buf = new StringBuilder("{ "+ recordMeta.getTableName() + " ");
        for ( Object propName: PropertyUtils.describe(bean).keySet() ) {
            buf.append(getObject((String)propName) + "");
            buf.append(", ");
        }
        buf.append("}");
        return buf.toString();
        } catch (Exception ex) {throw new DException(ex);}
    }

    /** Called whenever the record is updated or inserted, override in subtypes.
     * Mainly used to validate.  Use onPostUpSert to update related tables.
     */
    public void onPreUpSert(DConnection connection, QueryMode mode) {}
    public enum QueryMode {INSERT, UPDATE}

    ///////////////////////////

    public DRecordMeta getRecordMeta() {
        return recordMeta;
    }
}