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Diffstat (limited to 'sangria-contextual/src/main/java/com/tavianator/sangria/contextual/ContextSensitiveProvider.java')
-rw-r--r-- | sangria-contextual/src/main/java/com/tavianator/sangria/contextual/ContextSensitiveProvider.java | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/sangria-contextual/src/main/java/com/tavianator/sangria/contextual/ContextSensitiveProvider.java b/sangria-contextual/src/main/java/com/tavianator/sangria/contextual/ContextSensitiveProvider.java new file mode 100644 index 0000000..7d368f1 --- /dev/null +++ b/sangria-contextual/src/main/java/com/tavianator/sangria/contextual/ContextSensitiveProvider.java @@ -0,0 +1,55 @@ +/********************************************************************* + * Sangria * + * Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.com> * + * * + * This library is free software. It comes without any warranty, to * + * the extent permitted by applicable law. You can redistribute it * + * and/or modify it under the terms of the Do What The Fuck You Want * + * To Public License, Version 2, as published by Sam Hocevar. See * + * the COPYING file or http://www.wtfpl.net/ for more details. * + *********************************************************************/ + +package com.tavianator.sangria.contextual; + +import com.google.inject.Provider; +import com.google.inject.spi.InjectionPoint; + +/** + * Like a {@link Provider}, but with knowledge of the target {@link InjectionPoint}. + * + * <p> + * This interface, along with {@link ContextSensitiveBinder}, is useful for injecting custom logger types, among other + * things. However, context-sensitive injections can make maintenance and debugging more difficult. + * </p> + * + * @author Tavian Barnes (tavianator@tavianator.com) + * @version 1.0 + * @since 1.0 + */ +public interface ContextSensitiveProvider<T> { + /** + * Provide an instance of {@code T} for the given context. + * + * @param injectionPoint The {@link InjectionPoint} for this provision. + * @return An instance of {@code T}. + */ + T getInContext(InjectionPoint injectionPoint); + + /** + * Provide an instance of {@code T} for an unknown context. + * <p> + * The {@link InjectionPoint} may not be known in all cases, for example if a {@code Provider<T>} is used instead + * of + * a bare {@code T}. This method will be called in those cases. + * </p> + * <p> + * One reasonable implementation is to return a generically applicable instance, such as an anonymous logger. + * Another valid implementation is to throw an unchecked exception; in that case, {@code Provider<T>} injections + * will fail. + * </p> + * + * @return An instance of {@code T} + * @throws RuntimeException If injection without a context is not supported. + */ + T getInUnknownContext(); +} |