org.springframework.jdbc.support.GeneratedKeyHolder.java Source code

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Here is the source code for org.springframework.jdbc.support.GeneratedKeyHolder.java

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/*
 * Copyright 2002-2018 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
 *
 *      https://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;
import org.springframework.lang.Nullable;

/**
 * The standard 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
 * {@link org.springframework.jdbc.object.SqlUpdate} methods.
 *
 * @author Thomas Risberg
 * @author Juergen Hoeller
 * @since 1.1
 */
public class GeneratedKeyHolder implements KeyHolder {

    private final List<Map<String, Object>> 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<Map<String, Object>> keyList) {
        this.keyList = keyList;
    }

    @Override
    @Nullable
    public Number getKey() throws InvalidDataAccessApiUsageException, DataRetrievalFailureException {
        if (this.keyList.isEmpty()) {
            return null;
        }
        if (this.keyList.size() > 1 || 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<Object> keyIter = 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.");
        }
    }

    @Override
    @Nullable
    public Map<String, Object> getKeys() throws InvalidDataAccessApiUsageException {
        if (this.keyList.isEmpty()) {
            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 this.keyList.get(0);
    }

    @Override
    public List<Map<String, Object>> getKeyList() {
        return this.keyList;
    }

}