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/*
* Copyright 2019-2023 Google LLC
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
package com.google.cloud.spanner.hibernate;
import com.google.cloud.spanner.hibernate.BitReversedSequenceStyleGenerator.ReplaceInitCommand;
import com.google.cloud.spanner.hibernate.schema.RunBatchDdl;
import com.google.cloud.spanner.hibernate.schema.SpannerDatabaseInfo;
import com.google.cloud.spanner.hibernate.schema.SpannerTableStatements;
import com.google.cloud.spanner.hibernate.schema.TableDependencyTracker;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;
import org.hibernate.boot.Metadata;
import org.hibernate.boot.model.relational.InitCommand;
import org.hibernate.boot.model.relational.SqlStringGenerationContext;
import org.hibernate.mapping.Column;
import org.hibernate.mapping.Constraint;
import org.hibernate.mapping.Table;
import org.hibernate.mapping.UniqueKey;
import org.hibernate.tool.schema.Action;
import org.hibernate.tool.schema.spi.Exporter;
/**
* The exporter for Cloud Spanner CREATE and DROP table statements.
*
* @author Chengyuan Zhao
*/
public class SpannerTableExporter implements Exporter
{
private final SpannerTableStatements spannerTableStatements;
private final TableDependencyTracker tableDependencyTracker;
/**
* Constructor.
*
* @param spannerDialect a Cloud Spanner dialect.
*/
public SpannerTableExporter(SpannerDialect spannerDialect) {
this.spannerTableStatements = new SpannerTableStatements(spannerDialect);
this.tableDependencyTracker = new TableDependencyTracker();
}
@Override
public String[] getSqlCreateStrings(
Table currentTable, Metadata metadata, SqlStringGenerationContext context) {
initializeUniqueConstraints(currentTable);
List sqlStrings = buildSqlStrings(currentTable, metadata, Action.CREATE);
applyInitCommands(currentTable, metadata, context);
return sqlStrings.toArray(new String[0]);
}
protected void applyInitCommands(
Table table, Metadata metadata, SqlStringGenerationContext context) {
List initCommands = table.getInitCommands(context);
// Use only the replaced commands if the list contains both normal InitCommands and
// ReplaceInitCommands.
if (initCommands.stream().anyMatch(ReplaceInitCommand.class::isInstance)
&& initCommands.stream().anyMatch(cmd -> !ReplaceInitCommand.class.isInstance(cmd))) {
initCommands =
initCommands.stream()
.filter(ReplaceInitCommand.class::isInstance)
.collect(Collectors.toList());
} else if (initCommands.stream().anyMatch(ReplaceInitCommand.class::isInstance)) {
// Only ReplaceInitCommands, but there is nothing to replace, so we return early.
return;
}
for (InitCommand initCommand : initCommands) {
addStatementAfterDdlBatch(metadata, initCommand.getInitCommands());
}
}
@Override
public String[] getSqlDropStrings(
Table currentTable, Metadata metadata, SqlStringGenerationContext context) {
initializeUniqueConstraints(currentTable);
return buildSqlStrings(currentTable, metadata, Action.DROP).toArray(new String[0]);
}
/**
* Initializes the table exporter for if a new create-table or drop-table sequence is starting.
*/
public void init(
Metadata metadata, SpannerDatabaseInfo spannerDatabaseInfo, Action schemaAction) {
tableDependencyTracker.initializeDependencies(metadata, schemaAction);
spannerTableStatements.initializeSpannerDatabaseInfo(spannerDatabaseInfo);
}
private List buildSqlStrings(Table currentTable, Metadata metadata, Action schemaAction) {
Collection
tablesToProcess = tableDependencyTracker.getDependentTables(currentTable);
return tablesToProcess.stream()
.flatMap(
table -> {
if (schemaAction == Action.CREATE) {
return spannerTableStatements.createTable(table, metadata).stream();
} else {
return spannerTableStatements.dropTable(table).stream();
}
})
.collect(Collectors.toList());
}
static void addStatementAfterDdlBatch(Metadata metadata, String[] statements) {
// Find the RunBatchDdl auxiliary object which can run statements after the DDL batch.
Optional runBatchDdl =
metadata.getDatabase().getAuxiliaryDatabaseObjects().stream()
.filter(RunBatchDdl.class::isInstance)
.map(obj -> (RunBatchDdl) obj)
.findFirst();
if (runBatchDdl.isPresent()) {
for (String statement : statements) {
runBatchDdl.get().addAfterDdlStatement(statement);
}
} else {
throw new IllegalStateException(
"Failed to generate statement to execute after DDL batch. "
+ "The Spanner dialect did not create auxiliary database objects correctly. "
+ "Please post a question to "
+ "https://github.com/GoogleCloudPlatform/google-cloud-spanner-hibernate/issues");
}
}
/**
* Processes the columns of the table and creates Unique Constraints for columns annotated
* with @Column(unique = true).
*/
private static void initializeUniqueConstraints(Table table) {
Iterator colIterator = table.getColumns().iterator();
while (colIterator.hasNext()) {
Column col = colIterator.next();
if (col.isUnique()) {
String name = Constraint.generateName("UK_", table, col);
UniqueKey uk = table.getOrCreateUniqueKey(name);
uk.addColumn(col);
}
}
}
}
