org.objectstyle.cayenne.access.DefaultResultIterator Maven / Gradle / Ivy
/* ====================================================================
*
* The ObjectStyle Group Software License, version 1.1
* ObjectStyle Group - http://objectstyle.org/
*
* Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
* of the software. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if any,
* must include the following acknowlegement:
* "This product includes software developed by independent contributors
* and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
* or promote products derived from this software without prior written
* permission. For written permission, email
* "andrus at objectstyle dot org".
*
* 5. Products derived from this software may not be called "ObjectStyle"
* or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
* names without prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals and hosted on ObjectStyle Group web site. For more
* information on the ObjectStyle Group, please see
* java.sql.ResultSet.
*
* For more information see Cayenne User Guide.
*
* @author Andrei Adamchik
* @deprecated Since 1.2 replaced by JDBCResultIterator.
*/
public class DefaultResultIterator implements ResultIterator {
private static Logger logObj = Logger.getLogger(DefaultResultIterator.class);
// Connection information
protected Connection connection;
protected Statement statement;
protected ResultSet resultSet;
// Result descriptor
protected org.objectstyle.cayenne.access.util.ResultDescriptor descriptor;
protected int mapCapacity;
protected boolean closingConnection;
protected boolean isClosed;
protected boolean nextRow;
protected int fetchedSoFar;
protected int fetchLimit;
/**
* Utility method to read stored procedure out parameters as a map.
* Returns an empty map if no out parameters exist.
*/
public static Map readProcedureOutParameters(
CallableStatement statement,
org.objectstyle.cayenne.access.util.ResultDescriptor resultDescriptor)
throws SQLException, Exception {
int resultWidth = resultDescriptor.getResultWidth();
if (resultWidth > 0) {
Map dataRow = new HashMap(resultWidth * 2, 0.75f);
ExtendedType[] converters = resultDescriptor.getConverters();
int[] jdbcTypes = resultDescriptor.getJdbcTypes();
String[] names = resultDescriptor.getNames();
int[] outParamIndexes = resultDescriptor.getOutParamIndexes();
// process result row columns,
for (int i = 0; i < outParamIndexes.length; i++) {
int index = outParamIndexes[i];
// note: jdbc column indexes start from 1, not 0 unlike everywhere else
Object val =
converters[index].materializeObject(
statement,
index + 1,
jdbcTypes[index]);
dataRow.put(names[index], val);
}
return dataRow;
}
return Collections.EMPTY_MAP;
}
public DefaultResultIterator(
Connection connection,
Statement statement,
ResultSet resultSet,
org.objectstyle.cayenne.access.util.ResultDescriptor descriptor,
int fetchLimit)
throws SQLException, CayenneException {
this.connection = connection;
this.statement = statement;
this.resultSet = resultSet;
this.descriptor = descriptor;
this.fetchLimit = fetchLimit;
this.mapCapacity = (int) Math.ceil((descriptor.getNames().length) / 0.75);
checkNextRow();
}
/**
* Moves internal ResultSet cursor position down one row.
* Checks if the next row is available.
*/
protected void checkNextRow() throws SQLException, CayenneException {
nextRow = false;
if ((fetchLimit <= 0 || fetchedSoFar < fetchLimit) && resultSet.next()) {
nextRow = true;
fetchedSoFar++;
}
}
/**
* Returns true if there is at least one more record
* that can be read from the iterator.
*/
public boolean hasNextRow() {
return nextRow;
}
/**
* Returns the next result row as a Map.
*/
public Map nextDataRow() throws CayenneException {
if (!hasNextRow()) {
throw new CayenneException("An attempt to read uninitialized row or past the end of the iterator.");
}
try {
// read
Map row = readDataRow();
// rewind
checkNextRow();
return row;
}
catch (SQLException sqex) {
throw new CayenneException("Exception reading ResultSet.", sqex);
}
}
/**
* Returns the number of columns in the result row.
*
* @since 1.0.6
*/
public int getDataRowWidth() {
return descriptor.getResultWidth();
}
/**
* Returns all unread data rows from ResultSet, closing
* this iterator if needed.
*/
public List dataRows(boolean close) throws CayenneException {
List list = new ArrayList();
try {
while (this.hasNextRow()) {
list.add(this.nextDataRow());
}
return list;
}
finally {
if (close) {
this.close();
}
}
}
/**
* Reads a row from the internal ResultSet at the current
* cursor position.
*/
protected Map readDataRow() throws SQLException, CayenneException {
try {
Map dataRow = new DataRow(mapCapacity);
ExtendedType[] converters = descriptor.getConverters();
int[] jdbcTypes = descriptor.getJdbcTypes();
String[] names = descriptor.getNames();
int resultWidth = names.length;
// process result row columns,
for (int i = 0; i < resultWidth; i++) {
// note: jdbc column indexes start from 1, not 0 unlike everywhere else
Object val =
converters[i].materializeObject(resultSet, i + 1, jdbcTypes[i]);
dataRow.put(names[i], val);
}
return dataRow;
}
catch (CayenneException cex) {
// rethrow unmodified
throw cex;
}
catch (Exception otherex) {
throw new CayenneException(
"Exception materializing column.",
Util.unwindException(otherex));
}
}
/**
* Reads a row from the internal ResultSet at the current
* cursor position, processing only columns that are part of the ObjectId
* of a target class.
*/
protected Map readIdRow(DbEntity entity) throws SQLException, CayenneException {
try {
Map idRow = new DataRow(2);
ExtendedType[] converters = descriptor.getConverters();
int[] jdbcTypes = descriptor.getJdbcTypes();
String[] names = descriptor.getNames();
int[] idIndex = descriptor.getIdIndexes(entity);
int len = idIndex.length;
for (int i = 0; i < len; i++) {
// dereference column index
int index = idIndex[i];
// note: jdbc column indexes start from 1, not 0 as in arrays
Object val =
converters[index].materializeObject(
resultSet,
index + 1,
jdbcTypes[index]);
idRow.put(names[index], val);
}
return idRow;
}
catch (CayenneException cex) {
// rethrow unmodified
throw cex;
}
catch (Exception otherex) {
logObj.warn("Error", otherex);
throw new CayenneException(
"Exception materializing id column.",
Util.unwindException(otherex));
}
}
/**
* Closes ResultIterator and associated ResultSet. This method must be
* called explicitly when the user is finished processing the records.
* Otherwise unused database resources will not be released properly.
*/
public void close() throws CayenneException {
if (!isClosed) {
nextRow = false;
StringWriter errors = new StringWriter();
PrintWriter out = new PrintWriter(errors);
try {
resultSet.close();
}
catch (SQLException e1) {
out.println("Error closing ResultSet");
e1.printStackTrace(out);
}
if (statement != null) {
try {
statement.close();
}
catch (SQLException e2) {
out.println("Error closing PreparedStatement");
e2.printStackTrace(out);
}
}
// close connection, if this object was explicitly configured to be
// responsible for doing it
if (connection != null && this.isClosingConnection()) {
try {
connection.close();
}
catch (SQLException e3) {
out.println("Error closing Connection");
e3.printStackTrace(out);
}
}
try {
out.close();
errors.close();
}
catch (IOException ioex) {
// this is totally unexpected,
// after all we are writing to the StringBuffer
// in the memory
}
StringBuffer buf = errors.getBuffer();
if (buf.length() > 0) {
throw new CayenneException("Error closing ResultIterator: " + buf);
}
isClosed = true;
}
}
/**
* Returns true if this iterator is responsible
* for closing its connection, otherwise a user of the iterator
* must close the connection after closing the iterator.
*/
public boolean isClosingConnection() {
return closingConnection;
}
/**
* Sets the closingConnection property.
*/
public void setClosingConnection(boolean flag) {
this.closingConnection = flag;
}
/**
* @see org.objectstyle.cayenne.access.ResultIterator#skipDataRow()
*/
public void skipDataRow() throws CayenneException {
if (!hasNextRow()) {
throw new CayenneException("An attempt to read uninitialized row or past the end of the iterator.");
}
try {
checkNextRow();
}
catch (SQLException sqex) {
throw new CayenneException("Exception reading ResultSet.", sqex);
}
}
/**
* Returns a map of ObjectId values from the next result row.
* Primary key columns are determined from the provided DbEntity.
*
* @since 1.1
*/
public Map nextObjectId(DbEntity entity) throws CayenneException {
if (!hasNextRow()) {
throw new CayenneException("An attempt to read uninitialized row or past the end of the iterator.");
}
try {
// read
Map row = readIdRow(entity);
// rewind
checkNextRow();
return row;
}
catch (SQLException sqex) {
throw new CayenneException("Exception reading ResultSet.", sqex);
}
}
}
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