Package com.google.inject.internal
Class BytecodeGen
- java.lang.Object
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- com.google.inject.internal.BytecodeGen
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public final class BytecodeGen extends java.lang.Object
Utility methods for runtime code generation and class loading. We use this stuff forfaster reflection
,method interceptors
and to proxy circular dependencies.When loading classes, we need to be careful of:
- Memory leaks. Generated classes need to be garbage collected in long-lived applications. Once an injector and any instances it created can be garbage collected, the corresponding generated classes should be collectable.
- Visibility. Containers like
OSGi
use class loader boundaries to enforce modularity at runtime.
For each generated class, there's multiple class loaders involved:
- The related class's class loader. Every generated class services exactly one user-supplied class. This class loader must be used to access members with protected and package visibility.
- Guice's class loader.
- Our bridge class loader. This is a child of the user's class loader. It selectively delegates to either the user's class loader (for user classes) or the Guice class loader (for internal classes that are used by the generated classes). This class loader that owns the classes generated by Guice.
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Nested Class Summary
Nested Classes Modifier and Type Class Description private static class
BytecodeGen.BridgeClassLoader
Loader for Guice-generated classes.private static class
BytecodeGen.SystemBridgeHolder
static class
BytecodeGen.Visibility
The required visibility of a user's class from a Guice-generated class.
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Field Summary
Fields Modifier and Type Field Description private static java.lang.String
CGLIB_PACKAGE
private static com.google.common.cache.LoadingCache<java.lang.ClassLoader,java.lang.ClassLoader>
CLASS_LOADER_CACHE
Weak cache of bridge class loaders that make the Guice implementation classes visible to various code-generated proxies of client classes.(package private) static java.lang.ClassLoader
GUICE_CLASS_LOADER
(package private) static java.lang.String
GUICE_INTERNAL_PACKAGE
ie.(package private) static java.util.logging.Logger
logger
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Constructor Summary
Constructors Constructor Description BytecodeGen()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description private static java.lang.ClassLoader
canonicalize(java.lang.ClassLoader classLoader)
Attempts to canonicalize null references to the system class loader.static java.lang.ClassLoader
getClassLoader(java.lang.Class<?> type)
Returns the class loader to host generated classes fortype
.private static java.lang.ClassLoader
getClassLoader(java.lang.Class<?> type, java.lang.ClassLoader delegate)
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Field Detail
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logger
static final java.util.logging.Logger logger
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GUICE_CLASS_LOADER
static final java.lang.ClassLoader GUICE_CLASS_LOADER
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GUICE_INTERNAL_PACKAGE
static final java.lang.String GUICE_INTERNAL_PACKAGE
ie. "com.google.inject.internal"
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CGLIB_PACKAGE
private static final java.lang.String CGLIB_PACKAGE
- See Also:
- Constant Field Values
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CLASS_LOADER_CACHE
private static final com.google.common.cache.LoadingCache<java.lang.ClassLoader,java.lang.ClassLoader> CLASS_LOADER_CACHE
Weak cache of bridge class loaders that make the Guice implementation classes visible to various code-generated proxies of client classes.
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Method Detail
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canonicalize
private static java.lang.ClassLoader canonicalize(java.lang.ClassLoader classLoader)
Attempts to canonicalize null references to the system class loader. May return null if for some reason the system loader is unavailable.
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getClassLoader
public static java.lang.ClassLoader getClassLoader(java.lang.Class<?> type)
Returns the class loader to host generated classes fortype
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getClassLoader
private static java.lang.ClassLoader getClassLoader(java.lang.Class<?> type, java.lang.ClassLoader delegate)
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