/**
* Copyright 2014 Netflix, Inc.
*
* Licensed 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 rx.internal.operators;
import rx.*;
import rx.
Observable.
Operator;
import rx.exceptions.*;
import rx.functions.*;
import rx.plugins.
RxJavaHooks;
/**
* An {@link Operator} that pairs up items emitted by a source {@link Observable} with the sequence of items
* emitted by the {@code Observable} that is derived from each item by means of a selector, and emits the
* results of this pairing.
*
* @param <T>
* the type of items emitted by the source {@code Observable}
* @param <U>
* the type of items emitted by the derived {@code Observable}s
* @param <R>
* the type of items to be emitted by this {@code Operator}
*/
public final class
OperatorMapPair<T, U, R> implements
Operator<
Observable<? extends R>, T> {
final
Func1<? super T, ? extends
Observable<? extends U>>
collectionSelector;
final
Func2<? super T, ? super U, ? extends R>
resultSelector;
/**
* Creates the function that generates a {@code Observable} based on an item emitted by another {@code Observable}.
*
* @param <T> the input value type
* @param <U> the value type of the generated Observable
* @param selector
* a function that accepts an item and returns an {@code Iterable} of corresponding items
* @return a function that converts an item emitted by the source {@code Observable} into an {@code Observable} that emits the items generated by {@code selector} operating on that item
*/
public static <T, U>
Func1<T,
Observable<U>>
convertSelector(final
Func1<? super T, ? extends
Iterable<? extends U>>
selector) {
return new
Func1<T,
Observable<U>>() {
@
SuppressWarnings("cast")
@
Override
public
Observable<U>
call(T
t1) {
return (
Observable<U>)
Observable.
from(
selector.
call(
t1));
}
};
}
public
OperatorMapPair(final
Func1<? super T, ? extends
Observable<? extends U>>
collectionSelector, final
Func2<? super T, ? super U, ? extends R>
resultSelector) {
this.
collectionSelector =
collectionSelector;
this.
resultSelector =
resultSelector;
}
@
Override
public
Subscriber<? super T>
call(final
Subscriber<? super
Observable<? extends R>>
o) {
MapPairSubscriber<T, U, R>
parent = new
MapPairSubscriber<T, U, R>(
o,
collectionSelector,
resultSelector);
o.
add(
parent);
return
parent;
}
static final class
MapPairSubscriber<T, U, R> extends
Subscriber<T> {
final
Subscriber<? super
Observable<? extends R>>
actual;
final
Func1<? super T, ? extends
Observable<? extends U>>
collectionSelector;
final
Func2<? super T, ? super U, ? extends R>
resultSelector;
boolean
done;
public
MapPairSubscriber(
Subscriber<? super
Observable<? extends R>>
actual,
Func1<? super T, ? extends
Observable<? extends U>>
collectionSelector,
Func2<? super T, ? super U, ? extends R>
resultSelector) {
this.
actual =
actual;
this.
collectionSelector =
collectionSelector;
this.
resultSelector =
resultSelector;
}
@
Override
public void
onNext(T
outer) {
Observable<? extends U>
intermediate;
try {
intermediate =
collectionSelector.
call(
outer);
} catch (
Throwable ex) {
Exceptions.
throwIfFatal(
ex);
unsubscribe();
onError(
OnErrorThrowable.
addValueAsLastCause(
ex,
outer));
return;
}
actual.
onNext(
intermediate.
map(new
OuterInnerMapper<T, U, R>(
outer,
resultSelector)));
}
@
Override
public void
onError(
Throwable e) {
if (
done) {
RxJavaHooks.
onError(
e);
return;
}
done = true;
actual.
onError(
e);
}
@
Override
public void
onCompleted() {
if (
done) {
return;
}
actual.
onCompleted();
}
@
Override
public void
setProducer(
Producer p) {
actual.
setProducer(
p);
}
}
static final class
OuterInnerMapper<T, U, R> implements
Func1<U, R> {
final T
outer;
final
Func2<? super T, ? super U, ? extends R>
resultSelector;
public
OuterInnerMapper(T
outer,
Func2<? super T, ? super U, ? extends R>
resultSelector) {
this.
outer =
outer;
this.
resultSelector =
resultSelector;
}
@
Override
public R
call(U
inner) {
return
resultSelector.
call(
outer,
inner);
}
}
}