org.hibernate.id.IdentityGenerator.java Source code

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Here is the source code for org.hibernate.id.IdentityGenerator.java

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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.id;

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.hibernate.AssertionFailure;
import org.hibernate.HibernateException;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.id.insert.AbstractReturningDelegate;
import org.hibernate.id.insert.AbstractSelectingDelegate;
import org.hibernate.id.insert.IdentifierGeneratingInsert;
import org.hibernate.id.insert.InsertGeneratedIdentifierDelegate;
import org.hibernate.id.insert.InsertSelectIdentityInsert;

/**
 * A generator for use with ANSI-SQL IDENTITY columns used as the primary key.
 * The IdentityGenerator for autoincrement/identity key generation.
 * <br><br>
 * Indicates to the <tt>Session</tt> that identity (ie. identity/autoincrement
 * column) key generation should be used.
 *
 * @author Christoph Sturm
 */
public class IdentityGenerator extends AbstractPostInsertGenerator {

    @Override
    public InsertGeneratedIdentifierDelegate getInsertGeneratedIdentifierDelegate(
            PostInsertIdentityPersister persister, Dialect dialect, boolean isGetGeneratedKeysEnabled)
            throws HibernateException {
        if (isGetGeneratedKeysEnabled) {
            return dialect.getIdentityColumnSupport().buildGetGeneratedKeysDelegate(persister, dialect);
        } else if (dialect.getIdentityColumnSupport().supportsInsertSelectIdentity()) {
            return new InsertSelectDelegate(persister, dialect);
        } else {
            return new BasicDelegate(persister, dialect);
        }
    }

    /**
     * Delegate for dealing with IDENTITY columns where the dialect supports returning
     * the generated IDENTITY value directly from the insert statement.
     */
    public static class InsertSelectDelegate extends AbstractReturningDelegate
            implements InsertGeneratedIdentifierDelegate {
        private final PostInsertIdentityPersister persister;
        private final Dialect dialect;

        public InsertSelectDelegate(PostInsertIdentityPersister persister, Dialect dialect) {
            super(persister);
            this.persister = persister;
            this.dialect = dialect;
        }

        @Override
        public IdentifierGeneratingInsert prepareIdentifierGeneratingInsert() {
            InsertSelectIdentityInsert insert = new InsertSelectIdentityInsert(dialect);
            insert.addIdentityColumn(persister.getRootTableKeyColumnNames()[0]);
            return insert;
        }

        @Override
        protected PreparedStatement prepare(String insertSQL, SharedSessionContractImplementor session)
                throws SQLException {
            return session.getJdbcCoordinator().getStatementPreparer().prepareStatement(insertSQL,
                    PreparedStatement.NO_GENERATED_KEYS);
        }

        @Override
        public Serializable executeAndExtract(PreparedStatement insert, SharedSessionContractImplementor session)
                throws SQLException {
            ResultSet rs = session.getJdbcCoordinator().getResultSetReturn().execute(insert);
            try {
                return IdentifierGeneratorHelper.getGeneratedIdentity(rs, persister.getRootTableKeyColumnNames()[0],
                        persister.getIdentifierType(), session.getJdbcServices().getJdbcEnvironment().getDialect());
            } finally {
                session.getJdbcCoordinator().getLogicalConnection().getResourceRegistry().release(rs, insert);
            }
        }

        public Serializable determineGeneratedIdentifier(SharedSessionContractImplementor session, Object entity) {
            throw new AssertionFailure("insert statement returns generated value");
        }
    }

    /**
     * Delegate for dealing with IDENTITY columns where the dialect requires an
     * additional command execution to retrieve the generated IDENTITY value
     */
    public static class BasicDelegate extends AbstractSelectingDelegate
            implements InsertGeneratedIdentifierDelegate {
        private final PostInsertIdentityPersister persister;
        private final Dialect dialect;

        public BasicDelegate(PostInsertIdentityPersister persister, Dialect dialect) {
            super(persister);
            this.persister = persister;
            this.dialect = dialect;
        }

        @Override
        public IdentifierGeneratingInsert prepareIdentifierGeneratingInsert() {
            IdentifierGeneratingInsert insert = new IdentifierGeneratingInsert(dialect);
            insert.addIdentityColumn(persister.getRootTableKeyColumnNames()[0]);
            return insert;
        }

        @Override
        protected String getSelectSQL() {
            return persister.getIdentitySelectString();
        }

        @Override
        protected Serializable getResult(SharedSessionContractImplementor session, ResultSet rs, Object object)
                throws SQLException {
            return IdentifierGeneratorHelper.getGeneratedIdentity(rs, persister.getRootTableKeyColumnNames()[0],
                    persister.getIdentifierType(), session.getJdbcServices().getJdbcEnvironment().getDialect());
        }
    }

}