Examples with UnionHolder org.apache.drill.exec.expr.holders.UnionHolder used on opensource projects

Example 1 with UnionHolder

use of org.apache.drill.exec.expr.holders.UnionHolder in project drill by apache.

the class DrillFuncHolder method convertReaderToHolder.

/**
 * Convert an input value holder (in the generated code) into a value
 * holder as declared on the input parameter.
 */
private void convertReaderToHolder(JCodeModel model, JBlock jBlock, HoldingContainer inputVariable, int currentIndex, ValueReference parameter) {
    JVar inputHolder = inputVariable.getHolder();
    MajorType inputSqlType = inputVariable.getMajorType();
    if (Types.isComplex(parameter.getType())) {
        // For complex data-types (repeated maps/lists/dicts) the input to the
        // aggregate will be a FieldReader. However, aggregate
        // functions like ANY_VALUE, will assume the input to be a
        // RepeatedMapHolder etc. Generate boilerplate code, to map
        // from FieldReader to respective Holder.
        // FooHolder param = new FooHolder();
        // param.reader = inputVar;
        JType holderClass = getParamClass(model, parameter, inputHolder.type());
        JAssignmentTarget holderVar = declare(jBlock, parameter, holderClass, JExpr._new(holderClass), currentIndex);
        jBlock.assign(holderVar.ref("reader"), inputHolder);
    } else if (Types.isUnion(inputSqlType)) {
        // Normally unions are generated as a UnionHolder. However, if a parameter
        // is a FieldReader, then we must generate the union as a UnionReader.
        // Then, if there is another function that use a holder, we can convert
        // from the UnionReader to a UnionHolder.
        // 
        // UnionHolder param = new UnionHolder();
        // inputVar.read(param);
        JType holderClass = model._ref(UnionHolder.class);
        JAssignmentTarget paramVar = jBlock.decl(holderClass, parameter.getName(), JExpr._new(holderClass));
        JInvocation readCall = inputHolder.invoke("read");
        readCall.arg(paramVar);
        jBlock.add(readCall);
    } else {
        throw new UnsupportedOperationException(String.format("Cannot convert values of type %s from a reader to a holder", inputSqlType.getMinorType().name()));
    }
}