JdbcMapper/beehive-jdbc-mapper/src/main/java/com/moparisthebest/jdbc/CachingRowToObjectMapper.java

92 lines
2.6 KiB
Java

package com.moparisthebest.jdbc;
import java.lang.reflect.AccessibleObject;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Map;
public class CachingRowToObjectMapper<T> extends RowToObjectMapper<T> {
protected final Map<ResultSetKey, FieldMapping> cache;
protected final ResultSetKey keys;
public CachingRowToObjectMapper(final Map<ResultSetKey, FieldMapping> cache, ResultSet resultSet, Class<T> returnTypeClass, Calendar cal, Class<?> mapValType) {
super(resultSet, returnTypeClass, cal, mapValType);
this.cache = cache;
try {
keys = new ResultSetKey(super.getKeysFromResultSet(), _returnTypeClass);
//System.out.printf("keys: %s\n", keys);
} catch (SQLException e) {
throw new MapperException("CachingRowToObjectMapper: SQLException: " + e.getMessage(), e);
}
}
@Override
protected String[] getKeysFromResultSet() throws SQLException {
return keys.keys;
}
@Override
protected void getFieldMappings() throws SQLException {
FieldMapping fm = cache.get(keys);
if (fm == null) {
//System.out.printf("cache miss, keys: %s\n", keys);
// generate and put into cache
super.getFieldMappings();
cache.put(keys, new FieldMapping(_fields, _fieldTypes));
} else {
//System.out.printf("cache hit, keys: %s\n", keys);
// load from cache
_fields = fm._fields;
_fieldTypes = fm._fieldTypes;
}
}
public static class ResultSetKey {
protected final String[] keys;
protected final Class<?> returnTypeClass;
public ResultSetKey(final String[] keys, final Class<?> returnTypeClass) {
this.keys = keys;
this.returnTypeClass = returnTypeClass;
}
@Override
public boolean equals(final Object o) {
if (this == o) return true;
if (!(o instanceof ResultSetKey)) return false;
final ResultSetKey that = (ResultSetKey) o;
return Arrays.equals(keys, that.keys) && (returnTypeClass != null ? returnTypeClass.equals(that.returnTypeClass) : that.returnTypeClass == null);
}
@Override
public int hashCode() {
int result = Arrays.hashCode(keys);
result = 31 * result + (returnTypeClass != null ? returnTypeClass.hashCode() : 0);
return result;
}
@Override
public String toString() {
return "ResultSetKey{" +
"keys=" + Arrays.toString(keys) +
", returnTypeClass=" + returnTypeClass +
'}';
}
}
static class FieldMapping {
public final AccessibleObject[] _fields;
public final int[] _fieldTypes;
private FieldMapping(AccessibleObject[] _fields, int[] _fieldTypes) {
this._fields = _fields;
this._fieldTypes = _fieldTypes;
}
}
}