CustomRewriteJob.java

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package org.apache.doris.nereids.jobs.rewrite;

import org.apache.doris.nereids.CascadesContext;
import org.apache.doris.nereids.PlanProcess;
import org.apache.doris.nereids.jobs.Job;
import org.apache.doris.nereids.jobs.JobContext;
import org.apache.doris.nereids.rules.RuleType;
import org.apache.doris.nereids.trees.plans.Plan;
import org.apache.doris.nereids.trees.plans.visitor.CustomRewriter;

import java.util.BitSet;
import java.util.Objects;
import java.util.function.Supplier;

/**
 * Custom rewrite the plan.
 * Just pass the plan node to the 'CustomRewriter', and the 'CustomRewriter' rule will handle it.
 * The 'CustomRewriter' rule use the 'Visitor' design pattern to implement the rule.
 * You can check the 'CustomRewriter' interface to see which rules use this way to do rewrite.
 */
public class CustomRewriteJob implements RewriteJob {

    private final RuleType ruleType;
    private final Supplier<CustomRewriter> customRewriter;

    /**
     * Constructor.
     */
    public CustomRewriteJob(Supplier<CustomRewriter> rewriter, RuleType ruleType) {
        this.ruleType = Objects.requireNonNull(ruleType, "ruleType cannot be null");
        this.customRewriter = Objects.requireNonNull(rewriter, "customRewriter cannot be null");
    }

    @Override
    public void execute(JobContext context) {
        BitSet disableRules = Job.getDisableRules(context);
        if (disableRules.get(ruleType.type())) {
            return;
        }
        CascadesContext cascadesContext = context.getCascadesContext();
        Plan root = cascadesContext.getRewritePlan();
        // COUNTER_TRACER.log(CounterEvent.of(Memo.get=-StateId(), CounterType.JOB_EXECUTION, group, logicalExpression,
        //         root));
        Plan rewrittenRoot = customRewriter.get().rewriteRoot(root, context);
        if (rewrittenRoot == null) {
            return;
        }

        // don't remove this comment, it can help us to trace some bug when developing.

        if (!root.deepEquals(rewrittenRoot)) {
            if (cascadesContext.showPlanProcess()) {
                PlanProcess planProcess = new PlanProcess(
                        ruleType.name(), root.treeString(), rewrittenRoot.treeString());
                cascadesContext.addPlanProcess(planProcess);
            }
        }
        cascadesContext.setRewritePlan(rewrittenRoot);
    }

    @Override
    public boolean isOnce() {
        return false;
    }

    public RuleType getRuleType() {
        return ruleType;
    }

}