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katcharovkatcharov
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Implement switch expression
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8 files changed

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‎driver-core/src/main/com/mongodb/client/model/expressions/Branches.java

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/*
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* Copyright 2008-present MongoDB, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.mongodb.client.model.expressions;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.function.Function;
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public final class Branches {
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Branches() {
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// package-private
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}
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private <T extends Expression, R extends Expression> BranchesIntermediary<T, R> with(final Function<T, SwitchCase<R>> switchCase) {
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List<Function<T, SwitchCase<R>>> v = new ArrayList<>();
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v.add(switchCase);
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return new BranchesIntermediary<>(v);
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}
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private static <T extends Expression> MqlExpression<?> mqlEx(final T value) {
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return (MqlExpression<?>) value;
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}
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// is fn
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> is(final Function<T, BooleanExpression> o, final Function<T, R> r) {
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return this.with(value -> new SwitchCase<>(o.apply(value), r.apply(value)));
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}
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// eq lt lte
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> eq(final T v, final Function<T, R> r) {
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return this.with(value -> new SwitchCase<>(value.eq(v), r.apply(value)));
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}
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> lt(final T v, final Function<T, R> r) {
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return this.with(value -> new SwitchCase<>(value.lt(v), r.apply(value)));
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}
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> lte(final T v, final Function<T, R> r) {
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return this.with(value -> new SwitchCase<>(value.lte(v), r.apply(value)));
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}
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// is type
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> isBoolean(final Function<BooleanExpression, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isBoolean(), r.apply((BooleanExpression) value)));
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}
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> isNumber(final Function<NumberExpression, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isNumber(), r.apply((NumberExpression) value)));
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}
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> isString(final Function<StringExpression, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isString(), r.apply((StringExpression) value)));
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}
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> isDate(final Function<DateExpression, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isDate(), r.apply((DateExpression) value)));
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}
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public <T extends Expression, R extends Expression, Q extends Expression> BranchesIntermediary<T, R> isArray(final Function<ArrayExpression<Q>, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isArray(), r.apply((ArrayExpression<Q>) value)));
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}
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> isDocument(final Function<DocumentExpression, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isDocument(), r.apply((DocumentExpression) value)));
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}
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public <T extends Expression, R extends Expression, Q extends Expression> BranchesIntermediary<T, R> isMap(final Function<MapExpression<Q>, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isDocument(), r.apply((MapExpression<Q>) value)));
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}
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public <T extends Expression, R extends Expression> BranchesIntermediary<T, R> isNull(final Function<Expression, R> isNull) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isNull(), isNull.apply(value)));
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}
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}

‎driver-core/src/main/com/mongodb/client/model/expressions/BranchesIntermediary.java

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/*
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* Copyright 2008-present MongoDB, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.mongodb.client.model.expressions;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.function.Function;
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public final class BranchesIntermediary<T extends Expression, R extends Expression> extends BranchesTerminal<T, R> {
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BranchesIntermediary(final List<Function<T, SwitchCase<R>>> branches) {
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super(branches, null);
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}
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private BranchesIntermediary<T, R> with(final Function<T, SwitchCase<R>> switchCase) {
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List<Function<T, SwitchCase<R>>> v = new ArrayList<>(this.getBranches());
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v.add(switchCase);
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return new BranchesIntermediary<>(v);
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}
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private static <T extends Expression> MqlExpression<?> mqlEx(final T value) {
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return (MqlExpression<?>) value;
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}
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// is fn
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public BranchesIntermediary<T, R> is(final Function<T, BooleanExpression> o, final Function<T, R> r) {
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return this.with(value -> new SwitchCase<>(o.apply(value), r.apply(value)));
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}
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// eq lt lte
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public BranchesIntermediary<T, R> eq(final T v, final Function<T, R> r) {
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return this.with(value -> new SwitchCase<>(value.eq(v), r.apply(value)));
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}
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public BranchesIntermediary<T, R> lt(final T v, final Function<T, R> r) {
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return this.with(value -> new SwitchCase<>(value.lt(v), r.apply(value)));
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}
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public BranchesIntermediary<T, R> lte(final T v, final Function<T, R> r) {
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return this.with(value -> new SwitchCase<>(value.lte(v), r.apply(value)));
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}
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// is type
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public BranchesIntermediary<T, R> isBoolean(final Function<BooleanExpression, R> r) {
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return this.with(v -> new SwitchCase<>(mqlEx(v).isBoolean(), r.apply((BooleanExpression) v)));
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}
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public BranchesIntermediary<T, R> isNumber(final Function<NumberExpression, R> r) {
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return this.with(v -> new SwitchCase<>(mqlEx(v).isNumber(), r.apply((NumberExpression) v)));
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}
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public BranchesIntermediary<T, R> isString(final Function<StringExpression, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isString(), r.apply((StringExpression) value)));
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}
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public BranchesIntermediary<T, R> isDate(final Function<DateExpression, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isDate(), r.apply((DateExpression) value)));
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}
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public <Q extends Expression> BranchesIntermediary<T, R> isArray(final Function<ArrayExpression<Q>, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isArray(), r.apply((ArrayExpression<Q>) value)));
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}
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public BranchesIntermediary<T, R> isDocument(final Function<DocumentExpression, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isDocument(), r.apply((DocumentExpression) value)));
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}
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public <Q extends Expression> BranchesIntermediary<T, R> isMap(final Function<MapExpression<Q>, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isDocument(), r.apply((MapExpression<Q>) value)));
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}
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public BranchesIntermediary<T, R> isNull(final Function<Expression, R> r) {
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return this.with(value -> new SwitchCase<>(mqlEx(value).isNull(), r.apply(value)));
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}
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public BranchesTerminal<T, R> defaults(final Function<T, R> r) {
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return this.withDefault(value -> r.apply(value));
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}
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}

‎driver-core/src/main/com/mongodb/client/model/expressions/BranchesTerminal.java

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/*
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* Copyright 2008-present MongoDB, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
11+
* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
14+
* limitations under the License.
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*/
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package com.mongodb.client.model.expressions;
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import com.mongodb.lang.Nullable;
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import java.util.List;
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import java.util.function.Function;
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public class BranchesTerminal<T extends Expression, R extends Expression> {
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private final List<Function<T, SwitchCase<R>>> branches;
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private final Function<T, R> defaults;
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BranchesTerminal(final List<Function<T, SwitchCase<R>>> branches, @Nullable final Function<T, R> defaults) {
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this.branches = branches;
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this.defaults = defaults;
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}
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protected BranchesTerminal<T, R> withDefault(final Function<T, R> defaults) {
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return new BranchesTerminal<>(branches, defaults);
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}
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protected List<Function<T, SwitchCase<R>>> getBranches() {
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return branches;
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}
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@Nullable
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protected Function<T, R> getDefaults() {
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return defaults;
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}
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}

‎driver-core/src/main/com/mongodb/client/model/expressions/Expression.java

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@@ -18,6 +18,8 @@
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import com.mongodb.annotations.Evolving;
2020

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import java.util.function.Function;
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/**
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* Expressions express values that may be represented in (or computations that
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* may be performed within) a MongoDB server. Each expression evaluates to some
@@ -114,4 +116,17 @@ public interface Expression {
114116
<T extends Expression> MapExpression<T> isMapOr(MapExpression<T> other);
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116118
StringExpression asString();
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/**
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* Applies the given function to this argument. Note that "apply" usually
122+
* applies functions to arguments; here, the parameters are reversed.
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*
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* @param f
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* @return
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* @param <T>
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* @param <R>
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*/
129+
<T extends Expression, R extends Expression> R apply(Function<T, R> f);
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<T0 extends Expression, R0 extends Expression> R0 switchMap(Function<Branches, BranchesTerminal<T0, R0>> switchMap);
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}

‎driver-core/src/main/com/mongodb/client/model/expressions/MqlExpression.java

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@@ -28,6 +28,7 @@
2828
import java.util.function.Function;
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3030
import static com.mongodb.client.model.expressions.Expressions.of;
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import static com.mongodb.client.model.expressions.Expressions.ofNull;
3132
import static com.mongodb.client.model.expressions.Expressions.ofStringArray;
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3334
final class MqlExpression<T extends Expression>
@@ -284,6 +285,11 @@ public DocumentExpression unsetField(final String fieldName) {
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285286
/** @see Expression */
286287

288+
@Override
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public <Q extends Expression, R extends Expression> R apply(final Function<Q, R> f) {
290+
return f.apply(this.assertImplementsAllExpressions());
291+
}
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287293
@Override
288294
public BooleanExpression eq(final Expression eq) {
289295
return new MqlExpression<>(ast("$eq", eq));
@@ -315,7 +321,7 @@ public BooleanExpression lte(final Expression lte) {
315321
}
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317323
public BooleanExpression isBoolean() {
318-
return new MqlExpression<>(ast("$type")).eq(of("bool"));
324+
return new MqlExpression<>(astWrapped("$type")).eq(of("bool"));
319325
}
320326

321327
@Override
@@ -342,7 +348,7 @@ public IntegerExpression isIntegerOr(final IntegerExpression other) {
342348
}
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344350
public BooleanExpression isString() {
345-
return new MqlExpression<>(ast("$type")).eq(of("string"));
351+
return new MqlExpression<>(astWrapped("$type")).eq(of("string"));
346352
}
347353

348354
@Override
@@ -351,7 +357,7 @@ public StringExpression isStringOr(final StringExpression other) {
351357
}
352358

353359
public BooleanExpression isDate() {
354-
return ofStringArray("date").contains(new MqlExpression<>(ast("$type")));
360+
return ofStringArray("date").contains(new MqlExpression<>(astWrapped("$type")));
355361
}
356362

357363
@Override
@@ -364,7 +370,7 @@ public BooleanExpression isArray() {
364370
}
365371

366372
public Expression ifNull(final Expression ifNull) {
367-
return new MqlExpression<>(ast("$ifNull", ifNull, Expressions.ofNull()))
373+
return new MqlExpression<>(ast("$ifNull", ifNull, ofNull()))
368374
.assertImplementsAllExpressions();
369375
}
370376

@@ -383,7 +389,7 @@ public <R extends Expression> ArrayExpression<R> isArrayOr(final ArrayExpression
383389
}
384390

385391
public BooleanExpression isDocument() {
386-
return new MqlExpression<>(ast("$type")).eq(of("object"));
392+
return new MqlExpression<>(astWrapped("$type")).eq(of("object"));
387393
}
388394

389395
@Override
@@ -400,6 +406,10 @@ public <R extends Expression> MapExpression<R> isMapOr(final MapExpression<R> ot
400406
return this.isMap().cond(this.assertImplementsAllExpressions(), other);
401407
}
402408

409+
public BooleanExpression isNull() {
410+
return this.eq(ofNull());
411+
}
412+
403413
@Override
404414
public StringExpression asString() {
405415
return new MqlExpression<>(astWrapped("$toString"));
@@ -412,6 +422,32 @@ private Function<CodecRegistry, AstPlaceholder> convertInternal(final String to,
412422
.append("to", new BsonString(to)));
413423
}
414424

425+
@Override
426+
public <T0 extends Expression, R0 extends Expression> R0 switchMap(
427+
final Function<Branches, BranchesTerminal<T0, R0>> switchMap) {
428+
T0 value = this.assertImplementsAllExpressions();
429+
BranchesTerminal<T0, R0> construct = switchMap.apply(new Branches());
430+
return switchMapInternal(value, construct);
431+
}
432+
433+
private <T0 extends Expression, R0 extends Expression> R0 switchMapInternal(
434+
final T0 value, final BranchesTerminal<T0, R0> construct) {
435+
return newMqlExpression((cr) -> {
436+
BsonArray branches = new BsonArray();
437+
for (Function<T0, SwitchCase<R0>> fn : construct.getBranches()) {
438+
SwitchCase<R0> result = fn.apply(value);
439+
branches.add(new BsonDocument()
440+
.append("case", extractBsonValue(cr, result.getCaseValue()))
441+
.append("then", extractBsonValue(cr, result.getThenValue())));
442+
}
443+
BsonDocument switchBson = new BsonDocument().append("branches", branches);
444+
if (construct.getDefaults() != null) {
445+
switchBson = switchBson.append("default", extractBsonValue(cr, construct.getDefaults().apply(value)));
446+
}
447+
return astDoc("$switch", switchBson);
448+
});
449+
}
450+
415451
@Override
416452
public IntegerExpression parseInteger() {
417453
Expression asLong = new MqlExpression<>(ast("$toLong"));

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