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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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
*
* http://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 com.arakelian.jdbc.handler;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Timestamp;
import com.google.common.base.Preconditions;
/**
* ResultSetHandler implementation that converts one ResultSet column into
* an Object.
*
* @param
* scalar type
*/
public class ScalarHandler implements ResultSetHandler {
private static final int TYPE_UNKNOWN = 0;
private static final int TYPE_OBJECT = 1;
private static final int TYPE_STRING = 2;
private static final int TYPE_INTEGER = 3;
private static final int TYPE_BOOLEAN = 4;
private static final int TYPE_LONG = 5;
private static final int TYPE_DOUBLE = 6;
private static final int TYPE_FLOAT = 7;
private static final int TYPE_SHORT = 8;
private static final int TYPE_BYTE = 9;
private static final int TYPE_TIMESTAMP = 10;
/**
* True if handle returned last record
*/
private boolean eof;
/**
* The column number to retrieve.
*/
private int columnIndex;
/**
* The column name to retrieve. Either columnName or columnIndex will be used but never both.
*/
private String columnName;
/**
* Request type
*/
private final Class type;
/**
* Conversion type
*/
private final int conversionType;
/**
* Creates a new instance of ScalarHandler. The first column will be returned from
* handle().
*
* @param type
* scalar type
*/
public ScalarHandler(final Class type) {
this(1, type);
}
/**
* Creates a new instance of ScalarHandler.
*
* @param columnIndex
* The index of the column to retrieve from the ResultSet (1-based).
* @param type
* scalar type
*/
public ScalarHandler(final int columnIndex, final Class type) {
this.columnIndex = columnIndex;
this.type = Preconditions.checkNotNull(type);
this.conversionType = getConversionType();
if (conversionType == TYPE_UNKNOWN) {
throw new IllegalStateException();
}
}
/**
* Creates a new instance of ScalarHandler.
*
* @param columnName
* The name of the column to retrieve from the ResultSet.
* @param type
* scalar type
*/
public ScalarHandler(final String columnName, final Class type) {
this.columnName = columnName;
this.type = Preconditions.checkNotNull(type);
this.conversionType = getConversionType();
if (conversionType == TYPE_UNKNOWN) {
throw new IllegalStateException();
}
}
public final int getColumnIndex() {
return columnIndex;
}
public final String getColumnName() {
return columnName;
}
public final Class getType() {
return type;
}
/**
* Returns one ResultSet column as an object via the
* ResultSet.getObject() method that performs type conversions.
*
* @param rs
* ResultSet to process.
* @return The column or null if there are no rows in the ResultSet.
*
* @throws SQLException
* if a database access error occurs
*/
@Override
@SuppressWarnings("unchecked")
public T handle(final ResultSet rs, final ResultSetMetaData rsmd) throws SQLException {
if (rs.next()) {
if (columnIndex < 0) {
columnIndex = rs.findColumn(columnName);
}
switch (conversionType) {
case TYPE_OBJECT:
return (T) rs.getObject(columnIndex);
case TYPE_STRING:
return (T) rs.getString(columnIndex);
case TYPE_INTEGER:
final int intValue = rs.getInt(columnIndex);
if (rs.wasNull()) {
return null;
}
return (T) Integer.valueOf(intValue);
case TYPE_BOOLEAN:
final boolean boolVal = rs.getBoolean(columnIndex);
if (rs.wasNull()) {
return null;
}
return (T) Boolean.valueOf(boolVal);
case TYPE_LONG:
final long longVal = rs.getLong(columnIndex);
if (rs.wasNull()) {
return null;
}
return (T) Long.valueOf(longVal);
case TYPE_DOUBLE:
final double doubleVal = rs.getDouble(columnIndex);
if (rs.wasNull()) {
return null;
}
return (T) Double.valueOf(doubleVal);
case TYPE_FLOAT:
final float floatVal = rs.getFloat(columnIndex);
if (rs.wasNull()) {
return null;
}
return (T) Float.valueOf(floatVal);
case TYPE_SHORT:
final short shortVal = rs.getShort(columnIndex);
if (rs.wasNull()) {
return null;
}
return (T) Short.valueOf(shortVal);
case TYPE_BYTE:
final byte byteVal = rs.getByte(columnIndex);
if (rs.wasNull()) {
return null;
}
return (T) Byte.valueOf(byteVal);
case TYPE_TIMESTAMP:
return (T) rs.getTimestamp(columnIndex);
default:
throw new IllegalStateException();
}
} else {
eof = true;
return null;
}
}
public final void setColumnIndex(final int columnIndex) {
this.columnIndex = columnIndex;
}
public final void setColumnName(final String columnName) {
this.columnName = columnName;
}
@Override
public boolean wasLast(final T result) {
return eof;
}
private int getConversionType() {
if (type.equals(String.class)) {
return TYPE_STRING;
} else if (type.equals(Integer.TYPE) || type.equals(Integer.class)) {
return TYPE_INTEGER;
} else if (type.equals(Boolean.TYPE) || type.equals(Boolean.class)) {
return TYPE_BOOLEAN;
} else if (type.equals(Long.TYPE) || type.equals(Long.class)) {
return TYPE_LONG;
} else if (type.equals(Double.TYPE) || type.equals(Double.class)) {
return TYPE_DOUBLE;
} else if (type.equals(Float.TYPE) || type.equals(Float.class)) {
return TYPE_FLOAT;
} else if (type.equals(Short.TYPE) || type.equals(Short.class)) {
return TYPE_SHORT;
} else if (type.equals(Byte.TYPE) || type.equals(Byte.class)) {
return TYPE_BYTE;
} else if (type.equals(Timestamp.class)) {
return TYPE_TIMESTAMP;
} else if (type.equals(Object.class)) {
return TYPE_OBJECT;
} else {
return TYPE_UNKNOWN;
}
}
}
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