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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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* http://www.apache.org/licenses/LICENSE-2.0
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* KIND, either express or implied. See the License for the
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package org.apache.cayenne.access.jdbc;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.apache.cayenne.CayenneException;
import org.apache.cayenne.DataRow;
import org.apache.cayenne.access.OperationObserver;
import org.apache.cayenne.access.QueryLogger;
import org.apache.cayenne.access.types.ExtendedTypeMap;
import org.apache.cayenne.dba.DbAdapter;
import org.apache.cayenne.map.EntityResolver;
import org.apache.cayenne.map.ObjAttribute;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.query.SQLAction;
import org.apache.cayenne.query.SQLTemplate;
import org.apache.cayenne.util.Util;
import org.apache.commons.collections.IteratorUtils;
/**
* Implements a strategy for execution of SQLTemplates.
*
* @since 1.2 replaces SQLTemplateExecutionPlan
*/
public class SQLTemplateAction implements SQLAction {
protected DbAdapter adapter;
protected SQLTemplate query;
protected ObjEntity entity;
/**
* @deprecated since 3.0 use a
* {@link #SQLTemplateAction(SQLTemplate, DbAdapter, EntityResolver)}
* constructor.
*/
public SQLTemplateAction(SQLTemplate query, DbAdapter adapter) {
this.query = query;
this.adapter = adapter;
}
/**
* @since 3.0
*/
public SQLTemplateAction(SQLTemplate query, DbAdapter adapter,
EntityResolver entityResolver) {
this.query = query;
this.adapter = adapter;
this.entity = query.getMetaData(entityResolver).getObjEntity();
}
/**
* Returns DbAdapter associated with this execution plan object.
*/
public DbAdapter getAdapter() {
return adapter;
}
/**
* Runs a SQLTemplate query, collecting all results. If a callback expects an iterated
* result, result processing is stopped after the first ResultSet is encountered.
*/
public void performAction(Connection connection, OperationObserver callback)
throws SQLException, Exception {
String template = extractTemplateString();
// sanity check - misconfigured templates
if (template == null) {
throw new CayenneException("No template string configured for adapter "
+ getAdapter().getClass().getName());
}
boolean loggable = QueryLogger.isLoggable();
int size = query.parametersSize();
SQLTemplateProcessor templateProcessor = new SQLTemplateProcessor();
// zero size indicates a one-shot query with no parameters
// so fake a single entry batch...
int batchSize = (size > 0) ? size : 1;
List<Number> counts = new ArrayList<Number>(batchSize);
Iterator<?> it = (size > 0) ? query.parametersIterator() : IteratorUtils
.singletonIterator(Collections.EMPTY_MAP);
for (int i = 0; i < batchSize; i++) {
Map nextParameters = (Map) it.next();
SQLStatement compiled = templateProcessor.processTemplate(
template,
nextParameters);
if (loggable) {
QueryLogger.logQuery(compiled.getSql(), Arrays.asList(compiled
.getBindings()));
}
execute(connection, callback, compiled, counts);
}
// notify of combined counts of all queries inside SQLTemplate multiplied by the
// number of parameter sets...
int[] ints = new int[counts.size()];
for (int i = 0; i < ints.length; i++) {
ints[i] = counts.get(i).intValue();
}
callback.nextBatchCount(query, ints);
}
protected void execute(
Connection connection,
OperationObserver callback,
SQLStatement compiled,
Collection<Number> updateCounts) throws SQLException, Exception {
long t1 = System.currentTimeMillis();
boolean iteratedResult = callback.isIteratedResult();
PreparedStatement statement = connection.prepareStatement(compiled.getSql());
try {
bind(statement, compiled.getBindings());
// process a mix of results
boolean isResultSet = statement.execute();
boolean firstIteration = true;
while (true) {
if (firstIteration) {
firstIteration = false;
}
else {
isResultSet = statement.getMoreResults();
}
if (isResultSet) {
ResultSet resultSet = statement.getResultSet();
if (resultSet != null) {
try {
processSelectResult(
compiled,
connection,
statement,
resultSet,
callback,
t1);
}
finally {
if (!iteratedResult) {
resultSet.close();
}
}
// ignore possible following update counts and bail early on
// iterated results
if (iteratedResult) {
break;
}
}
}
else {
int updateCount = statement.getUpdateCount();
if (updateCount == -1) {
break;
}
updateCounts.add(Integer.valueOf(updateCount));
QueryLogger.logUpdateCount(updateCount);
}
}
}
finally {
if (!iteratedResult) {
statement.close();
}
}
}
protected void processSelectResult(
SQLStatement compiled,
Connection connection,
Statement statement,
ResultSet resultSet,
OperationObserver callback,
long startTime) throws Exception {
boolean iteratedResult = callback.isIteratedResult();
ExtendedTypeMap types = adapter.getExtendedTypes();
RowDescriptorBuilder builder = configureRowDescriptorBuilder(compiled, resultSet);
JDBCResultIterator result = new JDBCResultIterator(
connection,
statement,
resultSet,
builder.getDescriptor(types));
LimitResultIterator it = new LimitResultIterator(result, getFetchOffset(), query.getFetchLimit());
if (!iteratedResult) {
List<DataRow> resultRows = it.dataRows(false);
QueryLogger.logSelectCount(resultRows.size(), System.currentTimeMillis()
- startTime);
callback.nextDataRows(query, resultRows);
}
else {
try {
result.setClosingConnection(true);
callback.nextDataRows(query, it);
}
catch (Exception ex) {
it.close();
throw ex;
}
}
}
/**
* @since 3.0
*/
protected RowDescriptorBuilder configureRowDescriptorBuilder(
SQLStatement compiled,
ResultSet resultSet) throws SQLException {
RowDescriptorBuilder builder = new RowDescriptorBuilder();
// SQLTemplate #result columns take precedence over other ways to determine the
// type
if (compiled.getResultColumns().length > 0) {
builder.setColumns(compiled.getResultColumns());
}
else {
builder.setResultSet(resultSet);
if (entity != null) {
// TODO: andrus 2008/03/28 support flattened attributes with aliases...
for (ObjAttribute attribute : entity.getAttributes()) {
String column = attribute.getDbAttributePath();
if (column == null || column.indexOf('.') > 0) {
continue;
}
builder.overrideColumnType(column, attribute.getType());
// note that some DB's (Oracle) also add default JDBC overrides for
// DbAttributes that have no ObjAttributes (very common for PK's). If
// we find that there is more than one such DB, we can make that a
// default policy.
}
}
}
if (query.getColumnNamesCapitalization() != null) {
if (SQLTemplate.LOWERCASE_COLUMN_NAMES.equals(query
.getColumnNamesCapitalization())) {
builder.useLowercaseColumnNames();
}
else if (SQLTemplate.UPPERCASE_COLUMN_NAMES.equals(query
.getColumnNamesCapitalization())) {
builder.useUppercaseColumnNames();
}
}
return builder;
}
/**
* Extracts a template string from a SQLTemplate query. Exists mainly for the benefit
* of subclasses that can customize returned template.
*
* @since 1.2
*/
protected String extractTemplateString() {
String sql = query.getTemplate(getAdapter().getClass().getName());
// note that we MUST convert line breaks to spaces. On some databases (DB2)
// queries with breaks simply won't run; the rest are affected by CAY-726.
return Util.stripLineBreaks(sql, " ");
}
/**
* Binds parameters to the PreparedStatement.
*/
protected void bind(PreparedStatement preparedStatement, ParameterBinding[] bindings)
throws SQLException, Exception {
// bind parameters
if (bindings.length > 0) {
int len = bindings.length;
for (int i = 0; i < len; i++) {
adapter.bindParameter(
preparedStatement,
bindings[i].getValue(),
i + 1,
bindings[i].getJdbcType(),
bindings[i].getPrecision());
}
}
}
/**
* Always returns true.
*
* @deprecated since 3.0
*/
public boolean isRemovingLineBreaks() {
return true;
}
/**
* @deprecated since 3.0 - does nothing
*/
public void setRemovingLineBreaks(boolean removingLineBreaks) {
}
/**
* Returns a SQLTemplate for this action.
*/
public SQLTemplate getQuery() {
return query;
}
/**
* @since 3.0
*/
protected int getFetchOffset() {
return query.getFetchOffset();
}
}