rx.plugins.RxJavaErrorHandler Maven / Gradle / Ivy
/**
* 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.plugins;
import rx.*;
import rx.annotations.Beta;
import rx.exceptions.Exceptions;
/**
* Abstract class for defining error handling logic in addition to the normal
* {@link Subscriber#onError(Throwable)} behavior.
*
* For example, all {@code Exception}s can be logged using this handler even if
* {@link Subscriber#onError(Throwable)} is ignored or not provided when an {@link Observable} is subscribed to.
*
* This plugin is also responsible for augmenting rendering of {@code OnErrorThrowable.OnNextValue}.
*
* See {@link RxJavaPlugins} or the RxJava GitHub Wiki for information on configuring plugins: https://github.com/ReactiveX/RxJava/wiki/Plugins.
*/
public abstract class RxJavaErrorHandler {
/**
* Receives all {@code Exception}s from an {@link Observable} passed to
* {@link Subscriber#onError(Throwable)}.
*
* This should never throw an {@code Exception}. Make sure to try/catch({@code Throwable}) all code
* inside this method implementation.
*
* @param e
* the {@code Exception}
*/
public void handleError(Throwable e) {
// do nothing by default
}
protected static final String ERROR_IN_RENDERING_SUFFIX = ".errorRendering";
/**
* Receives items causing {@code OnErrorThrowable.OnNextValue} and gives a chance to choose the String
* representation of the item in the {@code OnNextValue} stacktrace rendering. Returns {@code null} if this
* type of item is not managed and should use default rendering.
*
* Note that primitive types are always rendered as their {@code toString()} value.
*
* If a {@code Throwable} is caught when rendering, this will fallback to the item's classname suffixed by
* {@value #ERROR_IN_RENDERING_SUFFIX}.
*
* @param item the last emitted item, that caused the exception wrapped in
* {@code OnErrorThrowable.OnNextValue}
* @return a short {@link String} representation of the item if one is known for its type, or null for
* default
* @since (if this graduates from Experimental/Beta to supported, replace this parenthetical with the
* release number)
*/
@Beta
public final String handleOnNextValueRendering(Object item) {
try {
return render(item);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
} catch (Throwable t) {
Exceptions.throwIfFatal(t);
}
return item.getClass().getName() + ERROR_IN_RENDERING_SUFFIX;
}
/**
* Override this method to provide rendering for specific types other than primitive types and null.
*
* For performance and overhead reasons, this should should limit to a safe production of a short
* {@code String} (as large renderings will bloat up the stacktrace). Prefer to try/catch({@code Throwable})
* all code inside this method implementation.
*
* If a {@code Throwable} is caught when rendering, this will fallback to the item's classname suffixed by
* {@value #ERROR_IN_RENDERING_SUFFIX}.
*
* @param item the last emitted item, that caused the exception wrapped in
* {@code OnErrorThrowable.OnNextValue}
* @return a short {@link String} representation of the item if one is known for its type, or null for
* default
* @throws InterruptedException if the rendering thread is interrupted
* @since (if this graduates from Experimental/Beta to supported, replace this parenthetical with the
* release number)
*/
@Beta
protected String render (Object item) throws InterruptedException {
//do nothing by default
return null;
}
}