com.avaje.ebeaninternal.server.persist.dml.DeleteMeta Maven / Gradle / Ivy

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/**
 * Copyright (C) 2006  Robin Bygrave
 * 
 * This file is part of Ebean.
 * 
 * Ebean is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *  
 * Ebean is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with Ebean; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA  
 */
package com.avaje.ebeaninternal.server.persist.dml;

import java.sql.SQLException;
import java.util.Set;

import com.avaje.ebeaninternal.server.core.ConcurrencyMode;
import com.avaje.ebeaninternal.server.core.PersistRequestBean;
import com.avaje.ebeaninternal.server.deploy.BeanDescriptor;
import com.avaje.ebeaninternal.server.persist.dmlbind.Bindable;

/**
 * Meta data for delete handler. The meta data is for a particular bean type. It
 * is considered immutable and is thread safe.
 */
public final class DeleteMeta {

	private final String sqlVersion;

	private final String sqlNone;

	private final Bindable id;

	private final Bindable version;

	private final Bindable all;

	private final String tableName;

	private final boolean emptyStringAsNull;
	
	public DeleteMeta(boolean emptyStringAsNull, BeanDescriptor desc, Bindable id, Bindable version, Bindable all) {
		this.emptyStringAsNull = emptyStringAsNull;
	    this.tableName = desc.getBaseTable();
		this.id = id;
		this.version = version;
		this.all = all;

		sqlNone = genSql(ConcurrencyMode.NONE);
		sqlVersion = genSql(ConcurrencyMode.VERSION);
	}
	
	public boolean isEmptyStringAsNull() {
        return emptyStringAsNull;
    }

    /**
	 * Return the table name.
	 */
	public String getTableName() {
		return tableName;
	}

	/**
	 * Bind the request based on the concurrency mode.
	 */
	public void bind(PersistRequestBean persist, DmlHandler bind)
			throws SQLException {

		Object bean = persist.getBean();

		id.dmlBind(bind, false, bean);

		switch (persist.getConcurrencyMode()) {
		case VERSION:
			version.dmlBind(bind, false, bean);
			break;

		case ALL:
			Object oldBean = persist.getOldValues();
			all.dmlBindWhere(bind, true, oldBean);
			break;

		default:
			break;
		}
	}

	/**
	 * get or generate the sql based on the concurrency mode.
	 */
	public String getSql(PersistRequestBean request) throws SQLException {

		
		switch (request.determineConcurrencyMode()) {
		case NONE:
			return sqlNone;
		
		case VERSION:
			return sqlVersion;
			
		case ALL:
			return genDynamicWhere(request.getLoadedProperties(), request.getOldValues());

		default:
			throw new RuntimeException("Invalid mode " + request.determineConcurrencyMode());
		}
	}

	private String genSql(ConcurrencyMode conMode) {

		// delete ... where bcol=? and bc1=? and bc2 is null and ...

		GenerateDmlRequest request = new GenerateDmlRequest(emptyStringAsNull);
				
		request.append("delete from ").append(tableName);
		request.append(" where ");

		request.setWhereIdMode();
		id.dmlAppend(request, false);

		if (ConcurrencyMode.VERSION.equals(conMode)) {
			if (version == null) {
				return null;
			}
			version.dmlAppend(request, false);

		} else if (ConcurrencyMode.ALL.equals(conMode)) {
			throw new RuntimeException("Never called for ConcurrencyMode.ALL");
		}

		return request.toString();
	}

	/**
	 * Generate the sql dynamically for where using IS NULL for binding null
	 * values.
	 */
	private String genDynamicWhere(Set includedProps, Object oldBean) throws SQLException {

		// always has a preceding id property(s) so the first
		// option is always ' and ' and not blank.
		
		GenerateDmlRequest request = new GenerateDmlRequest(emptyStringAsNull, includedProps, oldBean);

		request.append(sqlNone);

		request.setWhereMode();
		all.dmlWhere(request, true, oldBean);

		return request.toString();
	}

}