content: /*
   * 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.schema.impl;
  
  import org.apache.calcite.adapter.java.JavaTypeFactory;
  import org.apache.calcite.jdbc.CalciteConnection;
  import org.apache.calcite.jdbc.CalcitePrepare;
  import org.apache.calcite.jdbc.CalciteSchema;
  import org.apache.calcite.rel.type.RelDataTypeImpl;
  import org.apache.calcite.schema.FunctionParameter;
  import org.apache.calcite.schema.Schemas;
  import org.apache.calcite.schema.TableMacro;
  import org.apache.calcite.schema.TranslatableTable;
  
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.lang.reflect.Type;
  import java.util.Collections;
  import java.util.List;
  
  import static java.util.Objects.requireNonNull;
  
  /** Table function that implements a view. It returns the operator
   * tree of the view's SQL query. */
  public class ViewTableMacro implements TableMacro {
    protected final String viewSql;
    protected final CalciteSchema schema;
    private final @Nullable Boolean modifiable;
    /** Typically null. If specified, overrides the path of the schema as the
     * context for validating {@code viewSql}. */
    protected final @Nullable List<String> schemaPath;
    protected final @Nullable List<String> viewPath;
  
    /**
     * Creates a ViewTableMacro.
     *
     * @param schema     Root schema
     * @param viewSql    SQL defining the view
     * @param schemaPath Schema path relative to the root schema
     * @param viewPath   View path relative to the schema path
     * @param modifiable Request that a view is modifiable (dependent on analysis
     *                   of {@code viewSql})
     */
    public ViewTableMacro(CalciteSchema schema, String viewSql,
        @Nullable List<String> schemaPath, @Nullable List<String> viewPath,
        @Nullable Boolean modifiable) {
      this.viewSql = viewSql;
      this.schema = schema;
      this.viewPath = viewPath == null ? null : ImmutableList.copyOf(viewPath);
      this.modifiable = modifiable;
      this.schemaPath =
          schemaPath == null ? null : ImmutableList.copyOf(schemaPath);
    }
  
    @Override public List<FunctionParameter> getParameters() {
      return Collections.emptyList();
    }
  
    @Override public TranslatableTable apply(List<? extends @Nullable Object> arguments) {
      final CalciteConnection connection =
          MaterializedViewTable.MATERIALIZATION_CONNECTION;
      CalcitePrepare.AnalyzeViewResult parsed =
          Schemas.analyzeView(connection, schema, schemaPath, viewSql, viewPath,
              modifiable != null && modifiable);
      final List<String> schemaPath1 =
          schemaPath != null ? schemaPath : schema.path(null);
      if ((modifiable == null || modifiable)
          && parsed.modifiable
          && parsed.table != null) {
        return modifiableViewTable(parsed, viewSql, schemaPath1, viewPath, schema);
      } else {
        return viewTable(parsed, viewSql, schemaPath1, viewPath);
      }
    }
  
    /** Allows a sub-class to return an extension of {@link ModifiableViewTable}
     * by overriding this method. */
    protected ModifiableViewTable modifiableViewTable(CalcitePrepare.AnalyzeViewResult parsed,
        String viewSql, List<String> schemaPath, @Nullable List<String> viewPath,
        CalciteSchema schema) {
      final JavaTypeFactory typeFactory = (JavaTypeFactory) parsed.typeFactory;
      final Type elementType = typeFactory.getJavaClass(parsed.rowType);
      return new ModifiableViewTable(elementType,
          RelDataTypeImpl.proto(parsed.rowType), viewSql, schemaPath, viewPath,
          requireNonNull(parsed.table, "parsed.table"),
          Schemas.path(schema.root(), requireNonNull(parsed.tablePath, "parsed.tablePath")),
          requireNonNull(parsed.constraint, "parsed.constraint"),
          requireNonNull(parsed.columnMapping, "parsed.columnMapping"));
    }
  
    /** Allows a sub-class to return an extension of {@link ViewTable} by
     * overriding this method. */
    protected ViewTable viewTable(CalcitePrepare.AnalyzeViewResult parsed,
        String viewSql, List<String> schemaPath, @Nullable List<String> viewPath) {
      final JavaTypeFactory typeFactory = (JavaTypeFactory) parsed.typeFactory;
      final Type elementType = typeFactory.getJavaClass(parsed.rowType);
      return new ViewTable(elementType,
          RelDataTypeImpl.proto(parsed.rowType), viewSql, schemaPath, viewPath);
    }
  }
  