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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.
use datafusion::logical_expr::conditional_expressions::CaseBuilder;
use datafusion::prelude::Expr;
use pyo3::prelude::*;
use crate::errors::PyDataFusionResult;
use crate::expr::PyExpr;
// TODO(tsaucer) replace this all with CaseBuilder after it implements Clone
#[derive(Clone, Debug)]
#[pyclass(
from_py_object,
name = "CaseBuilder",
module = "datafusion.expr",
subclass,
frozen
)]
pub struct PyCaseBuilder {
expr: Option<Expr>,
when: Vec<Expr>,
then: Vec<Expr>,
}
#[pymethods]
impl PyCaseBuilder {
#[new]
pub fn new(expr: Option<PyExpr>) -> Self {
Self {
expr: expr.map(Into::into),
when: vec![],
then: vec![],
}
}
pub fn when(&self, when: PyExpr, then: PyExpr) -> PyCaseBuilder {
let mut case_builder = self.clone();
case_builder.when.push(when.into());
case_builder.then.push(then.into());
case_builder
}
fn otherwise(&self, else_expr: PyExpr) -> PyDataFusionResult<PyExpr> {
let case_builder = CaseBuilder::new(
self.expr.clone().map(Box::new),
self.when.clone(),
self.then.clone(),
Some(Box::new(else_expr.into())),
);
let expr = case_builder.end()?;
Ok(expr.into())
}
fn end(&self) -> PyDataFusionResult<PyExpr> {
let case_builder = CaseBuilder::new(
self.expr.clone().map(Box::new),
self.when.clone(),
self.then.clone(),
None,
);
let expr = case_builder.end()?;
Ok(expr.into())
}
}