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sualehsualeh
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Add empty catalog, so the server can come up even with bad or missing connection information
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4 files changed

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4 files changed

+302
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‎schemacrawler-ai-mcpserver/src/main/java/schemacrawler/tools/ai/mcpserver/EmptyCatalog.java‎

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package schemacrawler.tools.ai.mcpserver;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.Map;
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import java.util.Optional;
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import schemacrawler.schema.Catalog;
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import schemacrawler.schema.Column;
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import schemacrawler.schema.ColumnDataType;
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import schemacrawler.schema.CrawlInfo;
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import schemacrawler.schema.DatabaseInfo;
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import schemacrawler.schema.DatabaseUser;
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import schemacrawler.schema.JdbcDriverInfo;
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import schemacrawler.schema.NamedObject;
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import schemacrawler.schema.NamedObjectKey;
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import schemacrawler.schema.Reducer;
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import schemacrawler.schema.Routine;
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import schemacrawler.schema.Schema;
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import schemacrawler.schema.Sequence;
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import schemacrawler.schema.Synonym;
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import schemacrawler.schema.Table;
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public class EmptyCatalog implements Catalog {
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private static final long serialVersionUID = -8018517276190501450L;
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@Override
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public int compareTo(final NamedObject o) {
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return -1;
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}
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@Override
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public <T> T getAttribute(final String name) {
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return null;
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}
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@Override
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public <T> T getAttribute(final String name, final T defaultValue) throws ClassCastException {
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return null;
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}
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@Override
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public Map<String, Object> getAttributes() {
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return Collections.emptyMap();
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}
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@Override
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public Collection<ColumnDataType> getColumnDataTypes() {
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return Collections.emptyList();
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}
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@Override
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public Collection<ColumnDataType> getColumnDataTypes(final Schema schema) {
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return Collections.emptyList();
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}
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@Override
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public CrawlInfo getCrawlInfo() {
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throw new UnsupportedOperationException("No supported in an empty catalog");
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}
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@Override
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public DatabaseInfo getDatabaseInfo() {
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throw new UnsupportedOperationException("No supported in an empty catalog");
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}
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@Override
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public Collection<DatabaseUser> getDatabaseUsers() {
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return Collections.emptyList();
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}
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@Override
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public String getFullName() {
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return getName();
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}
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@Override
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public JdbcDriverInfo getJdbcDriverInfo() {
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throw new UnsupportedOperationException("No supported in an empty catalog");
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}
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@Override
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public String getName() {
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return "empty-catalog";
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}
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@Override
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public String getRemarks() {
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return getName();
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}
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@Override
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public Collection<Routine> getRoutines() {
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return Collections.emptyList();
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}
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@Override
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public Collection<Routine> getRoutines(final Schema schema) {
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return Collections.emptyList();
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}
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@Override
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public Collection<Routine> getRoutines(final Schema schema, final String routineName) {
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return Collections.emptyList();
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}
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@Override
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public Collection<Schema> getSchemas() {
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return Collections.emptyList();
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}
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@Override
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public Collection<Sequence> getSequences() {
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return Collections.emptyList();
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}
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@Override
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public Collection<Sequence> getSequences(final Schema schema) {
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return Collections.emptyList();
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}
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@Override
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public Collection<Synonym> getSynonyms() {
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return Collections.emptyList();
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}
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@Override
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public Collection<Synonym> getSynonyms(final Schema schema) {
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return Collections.emptyList();
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}
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@Override
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public Collection<ColumnDataType> getSystemColumnDataTypes() {
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return Collections.emptyList();
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}
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@Override
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public Collection<Table> getTables() {
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return Collections.emptyList();
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}
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@Override
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public Collection<Table> getTables(final Schema schema) {
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return Collections.emptyList();
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}
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@Override
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public boolean hasAttribute(final String name) {
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return false;
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}
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@Override
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public boolean hasRemarks() {
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return false;
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}
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@Override
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public NamedObjectKey key() {
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return new NamedObjectKey((String) null);
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}
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@Override
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public <T> Optional<T> lookupAttribute(final String name) {
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return Optional.empty();
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}
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@Override
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public Optional<Column> lookupColumn(
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final Schema schema, final String tableName, final String name) {
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return Optional.empty();
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}
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@Override
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public <C extends ColumnDataType> Optional<C> lookupColumnDataType(
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final Schema schema, final String dataTypeName) {
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return Optional.empty();
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}
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@Override
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public <S extends Schema> Optional<S> lookupSchema(final String name) {
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return Optional.empty();
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}
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@Override
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public <S extends Sequence> Optional<S> lookupSequence(
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final Schema schema, final String sequenceName) {
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return Optional.empty();
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}
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@Override
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public <S extends Synonym> Optional<S> lookupSynonym(
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final Schema schema, final String synonymName) {
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return Optional.empty();
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}
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@Override
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public <C extends ColumnDataType> Optional<C> lookupSystemColumnDataType(final String name) {
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return Optional.empty();
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}
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@Override
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public <T extends Table> Optional<T> lookupTable(final Schema schema, final String tableName) {
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return Optional.empty();
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}
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@Override
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public <N extends NamedObject> void reduce(final Class<N> clazz, final Reducer<N> reducer) {
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// No-op
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}
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@Override
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public void removeAttribute(final String name) {
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// No-op
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}
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@Override
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public <T> void setAttribute(final String name, final T value) {
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// No-op
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}
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@Override
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public void setRemarks(final String remarks) {
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// No-op
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}
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@Override
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public <N extends NamedObject> void undo(final Class<N> clazz, final Reducer<N> reducer) {
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// No-op
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}
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}

‎schemacrawler-ai-mcpserver/src/main/java/schemacrawler/tools/ai/mcpserver/EmptyDatabaseConnectionSource.java‎

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package schemacrawler.tools.ai.mcpserver;
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import java.sql.Connection;
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import java.sql.DriverManager;
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import java.sql.SQLException;
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import java.util.function.Consumer;
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import java.util.logging.Level;
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import java.util.logging.Logger;
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import schemacrawler.schemacrawler.exceptions.DatabaseAccessException;
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import us.fatehi.utility.datasource.DatabaseConnectionSource;
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public class EmptyDatabaseConnectionSource implements DatabaseConnectionSource {
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private static final Logger LOGGER =
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Logger.getLogger(EmptyDatabaseConnectionSource.class.getName());
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@Override
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public void close() throws Exception {
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// No-op
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}
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/** Get a connection to an empty SQLite in memory database. */
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@Override
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public Connection get() {
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try {
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final Connection connection = DriverManager.getConnection("jdbc:sqlite::memory:");
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return connection;
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} catch (final SQLException e) {
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final String message = "Could not create an empty connection";
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LOGGER.log(Level.WARNING, message, e);
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throw new DatabaseAccessException(message, e);
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}
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}
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@Override
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public boolean releaseConnection(final Connection connection) {
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return false;
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}
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@Override
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public void setFirstConnectionInitializer(final Consumer<Connection> connectionInitializer) {
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// No-op
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}
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}

‎schemacrawler-ai-mcpserver/src/main/java/schemacrawler/tools/ai/mcpserver/McpServerMain.java‎

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import static schemacrawler.tools.ai.mcpserver.McpServerUtility.startMcpServer;
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import java.util.logging.Level;
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import java.util.logging.Logger;
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import schemacrawler.schema.Catalog;
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import schemacrawler.schemacrawler.SchemaCrawlerOptions;
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import schemacrawler.tools.ai.mcpserver.server.ConfigurationManager;
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*/
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public class McpServerMain {
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private static final Logger LOGGER = Logger.getLogger(McpServerMain.class.getName());
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/**
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* Main method that reads environment variables, constructs arguments, and runs SchemaCrawler MCP
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* Server.
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public static void main(final String[] args) throws Exception {
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// Read options from environmental variable
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final McpServerContext context = new McpServerContext();
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final SchemaCrawlerOptions schemaCrawlerOptions = context.getSchemaCrawlerOptions();
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final DatabaseConnectionSource connectionSource =
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context.buildCatalogDatabaseConnectionSource();
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// Obtain the database catalog
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final Catalog catalog = SchemaCrawlerUtility.getCatalog(connectionSource, schemaCrawlerOptions);
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ConnectionService.instantiate(connectionSource);
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final Catalog catalog = getCatalog(context);
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ConfigurationManager.instantiate(catalog);
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// Start the MCP server
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startMcpServer(context.mcpTransport());
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}
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private static Catalog getCatalog(final McpServerContext context) {
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try {
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final SchemaCrawlerOptions schemaCrawlerOptions = context.getSchemaCrawlerOptions();
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final DatabaseConnectionSource connectionSource =
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context.buildCatalogDatabaseConnectionSource();
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// Obtain the database catalog
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final Catalog catalog =
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SchemaCrawlerUtility.getCatalog(connectionSource, schemaCrawlerOptions);
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ConnectionService.instantiate(connectionSource);
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return catalog;
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} catch (final Exception e) {
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LOGGER.log(Level.SEVERE, "Could not load catalog", e);
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if (!ConnectionService.isInstantiated()) {
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ConnectionService.instantiate(new EmptyDatabaseConnectionSource());
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}
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return new EmptyCatalog();
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}
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}
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}

‎schemacrawler-ai-mcpserver/src/main/java/schemacrawler/tools/ai/mcpserver/server/ConnectionService.java‎

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}
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}
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public static boolean isInstantiated() {
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return instance != null;
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}
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private static DatabaseConnectionSource newDatabaseConnectionSource(final Connection connection) {
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DatabaseConnectionSource dbConnectionSource = null;
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