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    • org.apache.calcite.avatica.Meta Maven / Gradle / Ivy

    /*
 * 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.calcite.avatica;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonProperty;

import java.lang.reflect.Field;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * Command handler for getting various metadata. Should be implemented by each
 * driver.
 *
 * 
    Also holds other abstract methods that are not related to metadata
 * that each provider must implement. This is not ideal.
    
 */
public interface Meta {
  String getSqlKeywords();

  String getNumericFunctions();

  String getStringFunctions();

  String getSystemFunctions();

  String getTimeDateFunctions();

  MetaResultSet getTables(String catalog,
      Pat schemaPattern,
      Pat tableNamePattern,
      List typeList);

  MetaResultSet getColumns(String catalog,
      Pat schemaPattern,
      Pat tableNamePattern,
      Pat columnNamePattern);

  MetaResultSet getSchemas(String catalog, Pat schemaPattern);

  MetaResultSet getCatalogs();

  MetaResultSet getTableTypes();

  MetaResultSet getProcedures(String catalog,
      Pat schemaPattern,
      Pat procedureNamePattern);

  MetaResultSet getProcedureColumns(String catalog,
      Pat schemaPattern,
      Pat procedureNamePattern,
      Pat columnNamePattern);

  MetaResultSet getColumnPrivileges(String catalog,
      String schema,
      String table,
      Pat columnNamePattern);

  MetaResultSet getTablePrivileges(String catalog,
      Pat schemaPattern,
      Pat tableNamePattern);

  MetaResultSet getBestRowIdentifier(String catalog,
      String schema,
      String table,
      int scope,
      boolean nullable);

  MetaResultSet getVersionColumns(String catalog, String schema, String table);

  MetaResultSet getPrimaryKeys(String catalog, String schema, String table);

  MetaResultSet getImportedKeys(String catalog, String schema, String table);

  MetaResultSet getExportedKeys(String catalog, String schema, String table);

  MetaResultSet getCrossReference(String parentCatalog,
      String parentSchema,
      String parentTable,
      String foreignCatalog,
      String foreignSchema,
      String foreignTable);

  MetaResultSet getTypeInfo();

  MetaResultSet getIndexInfo(String catalog,
      String schema,
      String table,
      boolean unique,
      boolean approximate);

  MetaResultSet getUDTs(String catalog,
      Pat schemaPattern,
      Pat typeNamePattern,
      int[] types);

  MetaResultSet getSuperTypes(String catalog,
      Pat schemaPattern,
      Pat typeNamePattern);

  MetaResultSet getSuperTables(String catalog,
      Pat schemaPattern,
      Pat tableNamePattern);

  MetaResultSet getAttributes(String catalog,
      Pat schemaPattern,
      Pat typeNamePattern,
      Pat attributeNamePattern);

  MetaResultSet getClientInfoProperties();

  MetaResultSet getFunctions(String catalog,
      Pat schemaPattern,
      Pat functionNamePattern);

  MetaResultSet getFunctionColumns(String catalog,
      Pat schemaPattern,
      Pat functionNamePattern,
      Pat columnNamePattern);

  MetaResultSet getPseudoColumns(String catalog,
      Pat schemaPattern,
      Pat tableNamePattern,
      Pat columnNamePattern);

  /** Creates an iterable for a result set.
   *
   * 
    The default implementation just returns {@code iterable}, which it
   * requires to be not null; derived classes may instead choose to execute the
   * relational expression in {@code signature}. */
  Iterable createIterable(StatementHandle handle, Signature signature,
      Iterable iterable);

  /** Prepares a statement.
   *
   * @param h Statement handle
   * @param sql SQL query
   * @param maxRowCount Negative for no limit (different meaning than JDBC)
   * @return Signature of prepared statement
   */
  Signature prepare(StatementHandle h, String sql, int maxRowCount);

  /** Prepares and executes a statement.
   *
   * @param h Statement handle
   * @param sql SQL query
   * @param maxRowCount Negative for no limit (different meaning than JDBC)
   * @param callback Callback to lock, clear and assign cursor
   * @return Signature of prepared statement
   */
  MetaResultSet prepareAndExecute(StatementHandle h, String sql,
      int maxRowCount, PrepareCallback callback);

  /** Called during the creation of a statement to allocate a new handle.
   *
   * @param ch Connection handle
   */
  StatementHandle createStatement(ConnectionHandle ch);

  /** Factory to create instances of {@link Meta}. */
  interface Factory {
    Meta create(List args);
  }

  /** Wrapper to remind API calls that a parameter is a pattern (allows '%' and
   * '_' wildcards, per the JDBC spec) rather than a string to be matched
   * exactly. */
  class Pat {
    public final String s;

    private Pat(String s) {
      this.s = s;
    }

    @JsonCreator
    public static Pat of(@JsonProperty("s") String name) {
      return new Pat(name);
    }
  }

  /** Meta data from which a result set can be constructed. */
  class MetaResultSet {
    public final int statementId;
    public final boolean ownStatement;
    public final Iterable iterable;
    public final Signature signature;

    public MetaResultSet(int statementId, boolean ownStatement,
        Signature signature, Iterable iterable) {
      this.signature = signature;
      this.statementId = statementId;
      this.ownStatement = ownStatement;
      this.iterable = iterable;
    }
  }

  /** Information necessary to convert an {@link Iterable} into a
   * {@link org.apache.calcite.avatica.util.Cursor}. */
  final class CursorFactory {
    public final Style style;
    public final Class clazz;
    @JsonIgnore
    public final List fields;
    public final List fieldNames;

    private CursorFactory(Style style, Class clazz, List fields,
        List fieldNames) {
      assert (fieldNames != null)
          == (style == Style.RECORD_PROJECTION || style == Style.MAP);
      assert (fields != null) == (style == Style.RECORD_PROJECTION);
      this.style = style;
      this.clazz = clazz;
      this.fields = fields;
      this.fieldNames = fieldNames;
    }

    @JsonCreator
    public static CursorFactory create(@JsonProperty("style") Style style,
        @JsonProperty("clazz") Class clazz,
        @JsonProperty("fieldNames") List fieldNames) {
      switch (style) {
      case OBJECT:
        return OBJECT;
      case ARRAY:
        return ARRAY;
      case LIST:
        return LIST;
      case RECORD:
        return record(clazz);
      case RECORD_PROJECTION:
        return record(clazz, null, fieldNames);
      case MAP:
        return map(fieldNames);
      default:
        throw new AssertionError("unknown style: " + style);
      }
    }

    public static final CursorFactory OBJECT =
        new CursorFactory(Style.OBJECT, null, null, null);

    public static final CursorFactory ARRAY =
        new CursorFactory(Style.ARRAY, null, null, null);

    public static final CursorFactory LIST =
        new CursorFactory(Style.LIST, null, null, null);

    public static CursorFactory record(Class resultClazz) {
      return new CursorFactory(Style.RECORD, resultClazz, null, null);
    }

    public static CursorFactory record(Class resultClass, List fields,
        List fieldNames) {
      if (fields == null) {
        fields = new ArrayList();
        for (String fieldName : fieldNames) {
          try {
            fields.add(resultClass.getField(fieldName));
          } catch (NoSuchFieldException e) {
            throw new RuntimeException(e);
          }
        }
      }
      return new CursorFactory(Style.RECORD_PROJECTION, resultClass, fields,
          fieldNames);
    }

    public static CursorFactory map(List fieldNames) {
      return new CursorFactory(Style.MAP, null, null, fieldNames);
    }

    public static CursorFactory deduce(List columns,
        Class resultClazz) {
      if (columns.size() == 1) {
        return OBJECT;
      } else if (resultClazz != null && !resultClazz.isArray()) {
        return record(resultClazz);
      } else {
        return ARRAY;
      }
    }
  }

  /** How logical fields are represented in the objects returned by the
   * iterator. */
  enum Style {
    OBJECT,
    RECORD,
    RECORD_PROJECTION,
    ARRAY,
    LIST,
    MAP
  }

  /** Result of preparing a statement. */
  class Signature {
    public final List columns;
    public final String sql;
    public final List parameters;
    public final Map internalParameters;
    public final CursorFactory cursorFactory;

    @JsonCreator
    public Signature(@JsonProperty("columns") List columns,
        @JsonProperty("sql") String sql,
        @JsonProperty("parameters") List parameters,
        @JsonProperty("internalParameters") Map
            internalParameters,
        @JsonProperty("cursorFactory") CursorFactory cursorFactory) {
      this.columns = columns;
      this.sql = sql;
      this.parameters = parameters;
      this.internalParameters = internalParameters;
      this.cursorFactory = cursorFactory;
    }

    /** Returns a copy of this Signature, substituting given CursorFactory. */
    public Signature setCursorFactory(CursorFactory cursorFactory) {
      return new Signature(columns, sql, parameters, internalParameters,
          cursorFactory);
    }
  }

  /** Connection handle. */
  class ConnectionHandle {
    public final int id;

    @Override public String toString() {
      return Integer.toString(id);
    }

    @JsonCreator
    public ConnectionHandle(@JsonProperty("id") int id) {
      this.id = id;
    }
  }

  /** Statement handle. */
  class StatementHandle {
    public final int id;

    @Override public String toString() {
      return Integer.toString(id);
    }

    @JsonCreator
    public StatementHandle(@JsonProperty("id") int id) {
      this.id = id;
    }
  }

  /** API to put a result set into a statement, being careful to enforce
   * thread-safety and not to overwrite existing open result sets. */
  interface PrepareCallback {
    Object getMonitor();
    void clear() throws SQLException;
    void assign(Signature signature, Iterable iterable)
        throws SQLException;
    void execute() throws SQLException;
  }
}

// End Meta.java
    
    
    
    

    




    
    
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