Spring Framework example source code file (GeneratedKeyHolder.java)

This example Spring Framework source code file (GeneratedKeyHolder.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

dataretrievalfailureexception, generatedkeyholder, invaliddataaccessapiusageexception, invaliddataaccessapiusageexception, iterator, list, map, map, number, number, object, the, the, unable, util

The Spring Framework GeneratedKeyHolder.java source code

/*
 * Copyright 2002-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.support;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.springframework.dao.DataRetrievalFailureException;
import org.springframework.dao.InvalidDataAccessApiUsageException;

/**
 * Default implementation of the {@link KeyHolder} interface, to be used for
 * holding auto-generated keys (as potentially returned by JDBC insert statements).
 *
 * <p>Create an instance of this class for each insert operation, and pass
 * it to the corresponding {@link org.springframework.jdbc.core.JdbcTemplate}
 * or {org.springframework.jdbc.object.SqlUpdate} methods.
 *
 * @author Thomas Risberg
 * @author Juergen Hoeller
 * @since 1.1
 */
public class GeneratedKeyHolder implements KeyHolder {

	private final List keyList;


	/**
	 * Create a new GeneratedKeyHolder with a default list.
	 */
	public GeneratedKeyHolder() {
		this.keyList = new LinkedList();
	}

	/**
	 * Create a new GeneratedKeyHolder with a given list.
	 * @param keyList a list to hold maps of keys
	 */
	public GeneratedKeyHolder(List keyList) {
		this.keyList = keyList;
	}


	public Number getKey() throws InvalidDataAccessApiUsageException, DataRetrievalFailureException {
		if (this.keyList.size() == 0) {
			return null;
		}
		if (this.keyList.size() > 1 || ((Map) this.keyList.get(0)).size() > 1) {
			throw new InvalidDataAccessApiUsageException(
					"The getKey method should only be used when a single key is returned.  " +
					"The current key entry contains multiple keys: " + this.keyList);
		}
		Iterator keyIter = ((Map) this.keyList.get(0)).values().iterator();
		if (keyIter.hasNext()) {
			Object key = keyIter.next();
			if (!(key instanceof Number)) {
				throw new DataRetrievalFailureException(
						"The generated key is not of a supported numeric type. " +
						"Unable to cast [" + (key != null ? key.getClass().getName() : null) +
						"] to [" + Number.class.getName() + "]");
			}
			return (Number) key;
		}
		else {
			throw new DataRetrievalFailureException("Unable to retrieve the generated key. " +
					"Check that the table has an identity column enabled.");
		}
	}

	public Map getKeys() throws InvalidDataAccessApiUsageException {
		if (this.keyList.size() == 0) {
			return null;
		}
		if (this.keyList.size() > 1)
			throw new InvalidDataAccessApiUsageException(
					"The getKeys method should only be used when keys for a single row are returned.  " +
					"The current key list contains keys for multiple rows: " + this.keyList);
		return (Map) this.keyList.get(0);
	}

	public List getKeyList() {
		return this.keyList;
	}

}