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.rel.core;
  
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelOptCost;
  import org.apache.calcite.plan.RelOptPlanner;
  import org.apache.calcite.plan.RelOptRule;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.AbstractRelNode;
  import org.apache.calcite.rel.RelInput;
  import org.apache.calcite.rel.RelWriter;
  import org.apache.calcite.rel.hint.Hintable;
  import org.apache.calcite.rel.hint.RelHint;
  import org.apache.calcite.rel.metadata.RelMetadataQuery;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeField;
  import org.apache.calcite.rex.RexDigestIncludeType;
  import org.apache.calcite.rex.RexLiteral;
  import org.apache.calcite.sql.SqlExplainLevel;
  import org.apache.calcite.sql.type.SqlTypeUtil;
  import org.apache.calcite.util.Pair;
  
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.function.Predicate;
  import java.util.stream.Collectors;
  
  /**
   * Relational expression whose value is a sequence of zero or more literal row
   * values.
   */
  public abstract class Values extends AbstractRelNode implements Hintable {
  
    public static final Predicate<? super Values> IS_EMPTY_J = Values::isEmpty;
  
    protected final ImmutableList<RelHint> hints;
  
    @SuppressWarnings("Guava")
    @Deprecated // to be removed before 2.0
    public static final com.google.common.base.Predicate<? super Values>
        IS_EMPTY = Values::isEmpty;
  
    @SuppressWarnings("Guava")
    @Deprecated // to be removed before 2.0
    public static final com.google.common.base.Predicate<? super Values>
        IS_NOT_EMPTY = Values::isNotEmpty;
  
    //~ Instance fields --------------------------------------------------------
  
    public final ImmutableList<ImmutableList<RexLiteral>> tuples;
  
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Creates a new Values.
     *
     * <p>Note that tuples passed in become owned by
     * this rel (without a deep copy), so caller must not modify them after this
     * call, otherwise bad things will happen.
     *
     * @param cluster Cluster that this relational expression belongs to
     * @param hints   Hints for this node
     * @param rowType Row type for tuples produced by this rel
     * @param tuples  2-dimensional array of tuple values to be produced; outer
     *                list contains tuples; each inner list is one tuple; all
     *                tuples must be of same length, conforming to rowType
     */
    @SuppressWarnings("method.invocation.invalid")
    protected Values(
        RelOptCluster cluster,
        List<RelHint> hints,
        RelDataType rowType,
        ImmutableList<ImmutableList<RexLiteral>> tuples,
        RelTraitSet traits) {
      super(cluster, traits);
      this.rowType = rowType;
      this.tuples = tuples;
      this.hints = ImmutableList.copyOf(hints);
      assert assertRowType();
    }
  
    /**
     * Creates a new Values.
     *
     * <p>Note that tuples passed in become owned by
     * this rel (without a deep copy), so caller must not modify them after this
     * call, otherwise bad things will happen.
     *
     * @param cluster Cluster that this relational expression belongs to
     * @param rowType Row type for tuples produced by this rel
     * @param tuples  2-dimensional array of tuple values to be produced; outer
     *                list contains tuples; each inner list is one tuple; all
     *                tuples must be of same length, conforming to rowType
     */
    @SuppressWarnings("method.invocation.invalid")
    protected Values(
        RelOptCluster cluster,
        RelDataType rowType,
        ImmutableList<ImmutableList<RexLiteral>> tuples,
        RelTraitSet traits) {
      this(cluster, Collections.emptyList(), rowType, tuples, traits);
    }
  
    /**
     * Creates a Values by parsing serialized output.
     */
    protected Values(RelInput input) {
      this(input.getCluster(), input.getRowType("type"),
          input.getTuples("tuples"), input.getTraitSet());
    }
  
    //~ Methods ----------------------------------------------------------------
  
    /** Predicate, to be used when defining an operand of a {@link RelOptRule},
     * that returns true if a Values contains zero tuples.
     *
     * <p>This is the conventional way to represent an empty relational
     * expression. There are several rules that recognize empty relational
     * expressions and prune away that section of the tree.
     */
    public static boolean isEmpty(Values values) {
      return values.getTuples().isEmpty();
    }
  
    /** Predicate, to be used when defining an operand of a {@link RelOptRule},
     * that returns true if a Values contains one or more tuples.
     *
     * <p>This is the conventional way to represent an empty relational
     * expression. There are several rules that recognize empty relational
     * expressions and prune away that section of the tree.
     */
    public static boolean isNotEmpty(Values values) {
      return !isEmpty(values);
    }
  
    public static boolean isSingleValue(Values values) {
      return values.tuples.size() == 1;
    }
  
    public ImmutableList<ImmutableList<RexLiteral>> getTuples(RelInput input) {
      return input.getTuples("tuples");
    }
  
    /** Returns the rows of literals represented by this Values relational
     * expression. */
    public ImmutableList<ImmutableList<RexLiteral>> getTuples() {
      return tuples;
    }
  
    /** Returns true if all tuples match rowType; otherwise, assert on
     * mismatch. */
    private boolean assertRowType() {
      RelDataType rowType = getRowType();
      for (List<RexLiteral> tuple : tuples) {
        assert tuple.size() == rowType.getFieldCount();
        for (Pair<RexLiteral, RelDataTypeField> pair
            : Pair.zip(tuple, rowType.getFieldList())) {
          RexLiteral literal = pair.left;
          RelDataType fieldType = pair.right.getType();
  
          // TODO jvs 19-Feb-2006: strengthen this a bit.  For example,
          // overflow, rounding, and padding/truncation must already have
          // been dealt with.
          if (!RexLiteral.isNullLiteral(literal)) {
            assert SqlTypeUtil.canAssignFrom(fieldType, literal.getType())
                : "to " + fieldType + " from " + literal;
          }
        }
      }
      return true;
    }
  
    @Override protected RelDataType deriveRowType() {
      if (rowType == null) {
        throw new AssertionError("rowType must not be null for " + this);
      }
      return rowType;
    }
  
    @Override public @Nullable RelOptCost computeSelfCost(RelOptPlanner planner,
        RelMetadataQuery mq) {
      double dRows = mq.getRowCount(this);
  
      // Assume CPU is negligible since values are precomputed.
      double dCpu = 1;
      double dIo = 0;
      return planner.getCostFactory().makeCost(dRows, dCpu, dIo);
    }
  
    // implement RelNode
    @Override public double estimateRowCount(RelMetadataQuery mq) {
      return tuples.size();
    }
  
    // implement RelNode
    @Override public RelWriter explainTerms(RelWriter pw) {
      // A little adapter just to get the tuples to come out
      // with curly brackets instead of square brackets.  Plus
      // more whitespace for readability.
      RelDataType rowType = getRowType();
      RelWriter relWriter = super.explainTerms(pw)
          // For rel digest, include the row type since a rendered
          // literal may leave the type ambiguous (e.g. "null").
          .itemIf("type", rowType,
              pw.getDetailLevel() == SqlExplainLevel.DIGEST_ATTRIBUTES)
          .itemIf("type", rowType.getFieldList(), pw.nest());
      if (pw.nest()) {
        pw.item("tuples", tuples);
      } else {
        pw.item("tuples",
            tuples.stream()
                .map(row -> row.stream()
                    .map(lit -> lit.computeDigest(RexDigestIncludeType.NO_TYPE))
                    .collect(Collectors.joining(", ", "{ ", " }")))
                .collect(Collectors.joining(", ", "[", "]")));
      }
      return relWriter;
    }
  
    @Override public ImmutableList<RelHint> getHints() {
      return hints;
    }
  }
  