How to use

isTrivial

method

in

org.apache.calcite.rel.rules.ProjectRemoveRule

    project.getRowType());
if (ProjectRemoveRule.isTrivial(newProj) &&

/**
 * Returns the child of a project if the project is trivial, otherwise
 * the project itself.
 */
public static RelNode strip(Project project) {
 return isTrivial(project) ? project.getInput() : project;
}

/**
 * Returns the child of a project if the project is trivial, otherwise
 * the project itself.
 */
public static RelNode strip(Project project) {
 return isTrivial(project) ? project.getInput() : project;
}

public static boolean isTrivialProject(Project project, boolean useNamesInIdentityProjCalc) {
 if (!useNamesInIdentityProjCalc) {
  return ProjectRemoveRule.isTrivial(project);
 }  else {
  return containIdentity(project.getProjects(), project.getRowType(), project.getInput().getRowType());
 }
}

public static boolean isTrivialProject(Project project, boolean useNamesInIdentityProjCalc) {
 if (!useNamesInIdentityProjCalc) {
  return ProjectRemoveRule.isTrivial(project);
 }  else {
  return containIdentity(project.getProjects(), project.getRowType(), project.getInput().getRowType());
 }
}

        proj.getRowType());
if (ProjectRemoveRule.isTrivial(newProj)) {
 call.transformTo(newScan);
} else {

public void onMatch(RelOptRuleCall call) {
 Project project = call.rel(0);
 assert isTrivial(project);
 RelNode stripped = project.getInput();
 if (stripped instanceof Project) {
  // Rename columns of child projection if desired field names are given.
  Project childProject = (Project) stripped;
  stripped = childProject.copy(childProject.getTraitSet(),
    childProject.getInput(), childProject.getProjects(),
    project.getRowType());
 }
 RelNode child = call.getPlanner().register(stripped, project);
 call.transformTo(child);
}

public void onMatch(RelOptRuleCall call) {
 Project project = call.rel(0);
 assert isTrivial(project);
 RelNode stripped = project.getInput();
 if (stripped instanceof Project) {
  // Rename columns of child projection if desired field names are given.
  Project childProject = (Project) stripped;
  stripped = childProject.copy(childProject.getTraitSet(),
    childProject.getInput(), childProject.getProjects(),
    project.getRowType());
 }
 RelNode child = call.getPlanner().register(stripped, project);
 call.transformTo(child);
}

if (ProjectRemoveRule.isTrivial(newProj)) {
 return (Prel) child;
} else {

@Override
public void onMatch(RelOptRuleCall call) {
 final Project proj = call.rel(0);
 final ScanCrel scan = call.rel(1);
 ProjectPushInfo columnInfo = PrelUtil.getColumns(scan.getRowType(), proj.getProjects());
 // get TableBase, either wrapped in RelOptTable, or TranslatableTable. TableBase table = scan.getTable().unwrap(TableBase.class);
 if (columnInfo == null || columnInfo.isStarQuery()) {
  return;
 }
 ScanCrel newScan = scan.cloneWithProject(columnInfo.columns);
 List<RexNode> newProjects = Lists.newArrayList();
 for (RexNode n : proj.getChildExps()) {
  newProjects.add(n.accept(columnInfo.getInputRewriter()));
 }
 final RelBuilder relBuilder = relBuilderFactory.create(proj.getCluster(), null);
 relBuilder.push(newScan);
 relBuilder.project(newProjects, proj.getRowType().getFieldNames());
 final RelNode newProj = relBuilder.build();
 if (newProj instanceof Project
   && ProjectRemoveRule.isTrivial((Project) newProj)
   && newScan.getRowType().getFullTypeString().equals(newProj.getRowType().getFullTypeString())) {
   call.transformTo(newScan);
 } else {
  if(newScan.getProjectedColumns().equals(scan.getProjectedColumns())) {
   // no point in doing a pushdown that doesn't change anything.
   return;
  }
  call.transformTo(newProj);
 }
}

  projectRel.getRowType());
if (ProjectRemoveRule.isTrivial(newProject)) {
 call.transformTo(newScan);
} else {

if (ProjectRemoveRule.isTrivial(newProj)) {
 return (Prel) child;
} else {

  project.getRowType());
if (ProjectRemoveRule.isTrivial(newTopProj)) {
 call.transformTo(newLogicalWindow);
} else {

  project.getRowType());
if (ProjectRemoveRule.isTrivial(newTopProj)) {
 call.transformTo(newLogicalWindow);
} else {

    project.getRowType());
if (ProjectRemoveRule.isTrivial(newProject)) {
 call.transformTo(newScan);
} else {

    project.getRowType());
if (ProjectRemoveRule.isTrivial(newProj) &&