/*
 * 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.type.descriptor.sql;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.sql.Blob;
import java.sql.Clob;
import java.sql.NClob;
import java.sql.Ref;
import java.sql.RowId;
import java.sql.SQLXML;
import java.sql.Struct;
import java.sql.Time;
import java.sql.Timestamp;
import java.sql.Types;
import java.util.Calendar;
import java.util.concurrent.ConcurrentHashMap;

import org.hibernate.mapping.Array;

import org.jboss.logging.Logger;

Maintains the JDBC recommended mappings for JDBC type-code to/from Java Class as defined in _Appendix B : Data Type Conversion Tables_ of the _JDBC 4.0 Specification_ Eventually, the plan is to have Dialect and DatabaseMetaData.getTypeInfo() contribute this information. 
Author:
Steve Ebersole/**
 * Maintains the JDBC recommended mappings for JDBC type-code to/from Java Class
 * as defined in _Appendix B : Data Type Conversion Tables_ of the _JDBC 4.0 Specification_
 *
 * Eventually, the plan is to have {@link org.hibernate.dialect.Dialect} and
 * {@link java.sql.DatabaseMetaData#getTypeInfo()} contribute this information.
 *
 * @author Steve Ebersole
 */
@SuppressWarnings("WeakerAccess")
public class JdbcTypeJavaClassMappings {
	private static final Logger log = Logger.getLogger( JdbcTypeJavaClassMappings.class );

	public static final JdbcTypeJavaClassMappings INSTANCE = new JdbcTypeJavaClassMappings();

	private final ConcurrentHashMap<Class, Integer> javaClassToJdbcTypeCodeMap;
	private final ConcurrentHashMap<Integer, Class> jdbcTypeCodeToJavaClassMap;

	private JdbcTypeJavaClassMappings() {
		javaClassToJdbcTypeCodeMap = buildJavaClassToJdbcTypeCodeMappings();
		jdbcTypeCodeToJavaClassMap = buildJdbcTypeCodeToJavaClassMappings();
	}

	
For the given Java type, determine the JDBC recommended JDBC type.
This includes the mappings defined in TABLE B-2 - Java Types Mapped to JDBC Types
as well as some additional "common sense" mappings for things like BigDecimal, BigInteger,
etc.
/**
	 * For the given Java type, determine the JDBC recommended JDBC type.
	 *
	 * This includes the mappings defined in <i>TABLE B-2 - Java Types Mapped to JDBC Types</i>
	 * as well as some additional "common sense" mappings for things like BigDecimal, BigInteger,
	 * etc.
	 */
	public int determineJdbcTypeCodeForJavaClass(Class cls) {
		Integer typeCode = javaClassToJdbcTypeCodeMap.get( cls );
		if ( typeCode != null ) {
			return typeCode;
		}

		int specialCode = cls.hashCode();
		log.debug(
				"JDBC type code mapping not known for class [" + cls.getName() + "]; using custom code [" + specialCode + "]"
		);
		return specialCode;
	}

	
For the given JDBC type, determine the JDBC recommended Java type.  These mappings
are defined by TABLE B-1 - JDBC Types Mapped to Java Types
/**
	 * For the given JDBC type, determine the JDBC recommended Java type.  These mappings
	 * are defined by <i>TABLE B-1 - JDBC Types Mapped to Java Types</i>
	 */
	public Class determineJavaClassForJdbcTypeCode(Integer typeCode) {
		Class cls = jdbcTypeCodeToJavaClassMap.get( typeCode );
		if ( cls != null ) {
			return cls;
		}

		log.debugf(
				"Java Class mapping not known for JDBC type code [%s]; using java.lang.Object",
				typeCode
		);
		return Object.class;
	}

	
See Also:
determineJavaClassForJdbcTypeCode(Integer)/**
	 * @see #determineJavaClassForJdbcTypeCode(Integer)
	 */
	public Class determineJavaClassForJdbcTypeCode(int typeCode) {
		return determineJavaClassForJdbcTypeCode( Integer.valueOf( typeCode ) );
	}


	// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	private static ConcurrentHashMap<Class, Integer> buildJavaClassToJdbcTypeCodeMappings() {
		final ConcurrentHashMap<Class, Integer> workMap = new ConcurrentHashMap<>();

		// these mappings are the ones outlined specifically in the spec
		workMap.put( String.class, Types.VARCHAR );
		workMap.put( BigDecimal.class, Types.NUMERIC );
		workMap.put( BigInteger.class, Types.NUMERIC );
		workMap.put( Boolean.class, Types.BIT );
		workMap.put( Short.class, Types.SMALLINT );
		workMap.put( Integer.class, Types.INTEGER );
		workMap.put( Long.class, Types.BIGINT );
		workMap.put( Float.class, Types.REAL );
		workMap.put( Double.class, Types.DOUBLE );
		workMap.put( byte[].class, Types.LONGVARBINARY );
		workMap.put( java.sql.Date.class, Types.DATE );
		workMap.put( Time.class, Types.TIME );
		workMap.put( Timestamp.class, Types.TIMESTAMP );
		workMap.put( Blob.class, Types.BLOB );
		workMap.put( Clob.class, Types.CLOB );
		workMap.put( Array.class, Types.ARRAY );
		workMap.put( Struct.class, Types.STRUCT );
		workMap.put( Ref.class, Types.REF );
		workMap.put( Class.class, Types.JAVA_OBJECT );
		workMap.put( RowId.class, Types.ROWID );
		workMap.put( SQLXML.class, Types.SQLXML );


		// additional "common sense" registrations
		workMap.put( Character.class, Types.CHAR );
		workMap.put( char[].class, Types.VARCHAR );
		workMap.put( Character[].class, Types.VARCHAR );
		workMap.put( Byte[].class, Types.LONGVARBINARY );
		workMap.put( java.util.Date.class, Types.TIMESTAMP );
		workMap.put( Calendar.class, Types.TIMESTAMP );

		return workMap;
	}

	private static ConcurrentHashMap<Integer, Class> buildJdbcTypeCodeToJavaClassMappings() {
		final ConcurrentHashMap<Integer, Class> workMap = new ConcurrentHashMap<>();

		workMap.put( Types.CHAR, String.class );
		workMap.put( Types.VARCHAR, String.class );
		workMap.put( Types.LONGVARCHAR, String.class );
		workMap.put( Types.NCHAR, String.class );
		workMap.put( Types.NVARCHAR, String.class );
		workMap.put( Types.LONGNVARCHAR, String.class );
		workMap.put( Types.NUMERIC, BigDecimal.class );
		workMap.put( Types.DECIMAL, BigDecimal.class );
		workMap.put( Types.BIT, Boolean.class );
		workMap.put( Types.BOOLEAN, Boolean.class );
		workMap.put( Types.TINYINT, Byte.class );
		workMap.put( Types.SMALLINT, Short.class );
		workMap.put( Types.INTEGER, Integer.class );
		workMap.put( Types.BIGINT, Long.class );
		workMap.put( Types.REAL, Float.class );
		workMap.put( Types.DOUBLE, Double.class );
		workMap.put( Types.FLOAT, Double.class );
		workMap.put( Types.BINARY, byte[].class );
		workMap.put( Types.VARBINARY, byte[].class );
		workMap.put( Types.LONGVARBINARY, byte[].class );
		workMap.put( Types.DATE, java.sql.Date.class );
		workMap.put( Types.TIME, Time.class );
		workMap.put( Types.TIMESTAMP, Timestamp.class );
		workMap.put( Types.BLOB, Blob.class );
		workMap.put( Types.CLOB, Clob.class );
		workMap.put( Types.NCLOB, NClob.class );
		workMap.put( Types.ARRAY, Array.class );
		workMap.put( Types.STRUCT, Struct.class );
		workMap.put( Types.REF, Ref.class );
		workMap.put( Types.JAVA_OBJECT, Class.class );
		workMap.put( Types.ROWID, RowId.class );
		workMap.put( Types.SQLXML, SQLXML.class );

		return workMap;
	}
}