com.ibm.fhir.persistence.jdbc.derby.DerbyCodeSystemDAO Maven / Gradle / Ivy
/*
* (C) Copyright IBM Corp. 2019, 2020
*
* SPDX-License-Identifier: Apache-2.0
*/
package com.ibm.fhir.persistence.jdbc.derby;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.ibm.fhir.persistence.jdbc.dao.api.FhirRefSequenceDAO;
import com.ibm.fhir.persistence.jdbc.dao.impl.CodeSystemDAOImpl;
import com.ibm.fhir.persistence.jdbc.exception.FHIRPersistenceDataAccessException;
/**
* Derby variant DAO used to manage code_systems records. Uses
* plain old JDBC statements instead of a stored procedure.
*
*/
public class DerbyCodeSystemDAO extends CodeSystemDAOImpl {
private final FhirRefSequenceDAO fhirRefSequenceDAO;
/**
* Public constructor
* @param c
* @param schemaName
*/
public DerbyCodeSystemDAO(Connection c, String schemaName) {
super(c, schemaName);
this.fhirRefSequenceDAO = new FhirRefSequenceDAOImpl(c);
}
@Override
public int readOrAddCodeSystem(String codeSystem) throws FHIRPersistenceDataAccessException {
// As the system is concurrent, we have to handle cases where another thread
// might create the entry after we selected and found nothing
Integer result = getCodeSystemId(codeSystem);
// Create the resource if we don't have it already (set by the continue handler)
if (result == null) {
try {
result = fhirRefSequenceDAO.nextValue();
String INS = "INSERT INTO code_systems (code_system_id, code_system_name) VALUES (?, ?)";
try (PreparedStatement stmt = getConnection().prepareStatement(INS)) {
// bind parameters
stmt.setInt(1, result);
stmt.setString(2, codeSystem);
stmt.executeUpdate();
}
} catch (SQLException e) {
if ("23505".equals(e.getSQLState())) {
// another thread snuck in and created the record, so we need to fetch the correct id
result = getCodeSystemId(codeSystem);
if (result == null) {
// This would be truly weird, but we protect against it anyway
throw new IllegalStateException("No code system returned after duplicate found!");
}
} else {
throw new FHIRPersistenceDataAccessException("codeSystem=" + codeSystem, e);
}
}
}
// There's no way result can be null here, so we're OK returning an int
return result;
}
/**
* Read the id for the named type
* @param codeSystem
* @return the database id, or null if the named record is not found
* @throws FHIRPersistenceDataAccessException
*/
protected Integer getCodeSystemId(String codeSystem) throws FHIRPersistenceDataAccessException {
Integer result;
String sql1 = "SELECT code_system_id FROM code_systems WHERE code_system_name = ?";
try (PreparedStatement stmt = getConnection().prepareStatement(sql1)) {
stmt.setString(1, codeSystem);
ResultSet rs = stmt.executeQuery();
if (rs.next()) {
result = rs.getInt(1);
} else {
result = null;
}
} catch (SQLException e) {
throw new FHIRPersistenceDataAccessException("codeSystem=" + codeSystem, e);
}
return result;
}
}