/*
Derby - Class org.apache.derby.impl.sql.GenericResultDescription
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 org.apache.derby.impl.sql;
import org.apache.derby.iapi.reference.SQLState;
import org.apache.derby.iapi.sql.ResultColumnDescriptor;
import org.apache.derby.iapi.sql.ResultDescription;
import org.apache.derby.iapi.services.sanity.SanityManager;
import org.apache.derby.iapi.services.io.StoredFormatIds;
import org.apache.derby.iapi.services.io.FormatIdUtil;
import org.apache.derby.iapi.services.io.Formatable;
import org.apache.derby.iapi.util.ReuseFactory;
import org.apache.derby.iapi.util.StringUtil;
import java.io.ObjectOutput;
import java.io.ObjectInput;
import java.io.IOException;
import java.sql.ResultSetMetaData;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* GenericResultDescription: basic implementation of result
* description, used in conjunction with the other
* implementations in this package. This implementation
* of ResultDescription may be used by anyone.
*
*/
public final class GenericResultDescription
implements ResultDescription, Formatable
{
/********************************************************
**
** This class implements Formatable. That means that it
** can write itself to and from a formatted stream. If
** you add more fields to this class, make sure that you
** also write/read them with the writeExternal()/readExternal()
** methods.
**
** If, inbetween releases, you add more fields to this class,
** then you should bump the version number emitted by the getTypeFormatId()
** method.
**
********************************************************/
private ResultColumnDescriptor[] columns;
private String statementType;
/**
* Saved JDBC ResultSetMetaData object.
* @see ResultDescription#setMetaData(java.sql.ResultSetMetaData)
*/
private transient ResultSetMetaData metaData;
/**
* A map which maps a column name to a column number.
* Entries only added when accessing columns with the name.
*/
private transient Map columnNameMap;
/**
* Niladic constructor for Formatable
*/
public GenericResultDescription()
{
}
/**
* Build a GenericResultDescription from columns and type
*
* @param columns an array of col descriptors
* @param statementType the type
*/
public GenericResultDescription(ResultColumnDescriptor[] columns,
String statementType)
{
this.columns = columns;
this.statementType = statementType;
}
//
// ResultDescription interface
//
/**
* @see ResultDescription#getStatementType
*/
public String getStatementType() {
return statementType;
}
/**
* @see ResultDescription#getColumnCount
*/
public int getColumnCount()
{
return (columns == null) ? 0 : columns.length;
}
public ResultColumnDescriptor[] getColumnInfo() {
return columns;
}
/**
* position is 1-based.
* @see ResultDescription#getColumnDescriptor
*/
public ResultColumnDescriptor getColumnDescriptor(int position) {
return columns[position-1];
}
//////////////////////////////////////////////
//
// FORMATABLE
//
//////////////////////////////////////////////
/**
* Write this object out
*
* @param out write bytes here
*
* @exception IOException thrown on error
*/
public void writeExternal(ObjectOutput out) throws IOException
{
int len = (columns == null) ? 0 : columns.length;
out.writeObject(statementType);
out.writeInt(len);
while(len-- > 0)
{
/*
** If we don't have a GenericColumnsDescriptor,
** create one now and use that to write out.
** Do this to avoid writing out query tree
** implementations of ResultColumnDescriptor
*/
if (!(columns[len] instanceof
GenericColumnDescriptor))
{
columns[len] = new GenericColumnDescriptor(columns[len]);
}
out.writeObject(columns[len]);
}
}
/**
* Read this object from a stream of stored objects.
*
* @param in read this.
*
* @exception IOException thrown on error
* @exception ClassNotFoundException thrown on error
*/
public void readExternal(ObjectInput in)
throws IOException, ClassNotFoundException
{
int len;
columns = null;
statementType = (String)in.readObject();
len = in.readInt();
if (len > 0)
{
columns = new GenericColumnDescriptor[len];
while(len-- > 0)
{
columns[len] = (ResultColumnDescriptor)in.readObject();
}
}
}
/**
* Get the formatID which corresponds to this class.
*
* @return the formatID of this class
*/
public int getTypeFormatId() { return StoredFormatIds.GENERIC_RESULT_DESCRIPTION_V01_ID; }
public String toString()
{
if (SanityManager.DEBUG)
{
StringBuffer colStr = new StringBuffer();
for (int i = 0; i < columns.length; i++)
{
colStr.append("column["+i+"]\n");
colStr.append(columns[i].toString());
}
return "GenericResultDescription\n" +
"\tStatementType = "+statementType+"\n" +
"\tCOLUMNS\n" + colStr.toString();
}
else
{
return "";
}
}
/**
* Set the meta data if it has not already been set.
*/
public synchronized void setMetaData(ResultSetMetaData rsmd) {
if (metaData == null)
metaData = rsmd;
}
/**
* Get the saved meta data.
*/
public synchronized ResultSetMetaData getMetaData() {
return metaData;
}
/**
* Find a column name based upon the JDBC rules for
* getXXX and setXXX. Name matching is case-insensitive,
* matching the first name (1-based) if there are multiple
* columns that map to the same name.
*/
public int findColumnInsenstive(String columnName) {
final Map workMap;
synchronized (this) {
if (columnNameMap==null) {
// updateXXX and getXXX methods are case insensitive and the
// first column should be returned. The loop goes backward to
// create a map which preserves this property.
Map map = new HashMap();
for (int i = getColumnCount(); i>=1; i--) {
final String key = StringUtil.
SQLToUpperCase(
getColumnDescriptor(i).getName());
final Integer value = ReuseFactory.getInteger(i);
map.put(key, value);
}
// Ensure this map can never change.
columnNameMap = Collections.unmodifiableMap(map);
}
workMap = columnNameMap;
}
Integer val = (Integer) workMap.get(columnName);
if (val==null) {
val = (Integer) workMap.get(StringUtil.SQLToUpperCase(columnName));
}
if (val==null) {
return -1;
} else {
return val.intValue();
}
}
}
|