org.apache.tajo.engine.codegen.CaseWhenSwitchGenerator.java Source code

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Here is the source code for org.apache.tajo.engine.codegen.CaseWhenSwitchGenerator.java

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/*
 * 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.tajo.engine.codegen;

import com.google.common.collect.Maps;
import org.apache.tajo.org.objectweb.asm.Label;
import org.apache.tajo.plan.expr.EvalNode;

import java.util.NavigableMap;
import java.util.Stack;

class CaseWhenSwitchGenerator implements TajoGeneratorAdapter.SwitchCaseGenerator {
    final private EvalCodeGenerator generator;
    final private EvalCodeGenContext context;
    final private Stack<EvalNode> stack;

    final NavigableMap<Integer, TajoGeneratorAdapter.SwitchCase> casesMap;
    final EvalNode defaultEval;

    public CaseWhenSwitchGenerator(EvalCodeGenerator generator, EvalCodeGenContext context, Stack<EvalNode> stack,
            TajoGeneratorAdapter.SwitchCase[] cases, EvalNode defaultEval) {
        this.generator = generator;
        this.context = context;
        this.stack = stack;
        this.casesMap = Maps.newTreeMap();
        for (TajoGeneratorAdapter.SwitchCase switchCase : cases) {
            this.casesMap.put(switchCase.key(), switchCase);
        }
        this.defaultEval = defaultEval;
    }

    @Override
    public int size() {
        return casesMap.size();
    }

    @Override
    public int min() {
        return casesMap.firstEntry().getKey();
    }

    @Override
    public int max() {
        return casesMap.lastEntry().getKey();
    }

    @Override
    public int key(int index) {
        return casesMap.get(index).key();
    }

    @Override
    public void generateCase(int key, Label end) {
        generator.visit(context, casesMap.get(key).result(), stack);
        context.gotoLabel(end);
    }

    public int[] keys() {
        int[] keys = new int[casesMap.size()];

        int idx = 0;
        for (int key : casesMap.keySet()) {
            keys[idx++] = key;
        }
        return keys;
    }

    public void generateDefault() {
        if (defaultEval != null) {
            generator.visit(context, defaultEval, stack);
        } else {
            context.pushNullOfThreeValuedLogic();
            context.pushNullFlag(false);
        }
    }
}