--- a/jdk/src/share/classes/java/lang/invoke/LambdaMetafactory.java Thu Oct 24 10:13:39 2013 -0700
+++ b/jdk/src/share/classes/java/lang/invoke/LambdaMetafactory.java Thu Oct 24 13:06:05 2013 -0400
@@ -29,88 +29,128 @@
import java.util.Arrays;
/**
- * <p>Bootstrap methods for converting lambda expressions and method references to functional interface objects.</p>
- *
- * <p>For every lambda expressions or method reference in the source code, there is a target type which is a
- * functional interface. Evaluating a lambda expression produces an object of its target type. The mechanism for
- * evaluating lambda expressions is to invoke an invokedynamic call site, which takes arguments describing the sole
- * method of the functional interface and the implementation method, and returns an object (the lambda object) that
- * implements the target type. Methods of the lambda object invoke the implementation method. For method
- * references, the implementation method is simply the referenced method; for lambda expressions, the
- * implementation method is produced by the compiler based on the body of the lambda expression. The methods in
- * this file are the bootstrap methods for those invokedynamic call sites, called lambda factories, and the
- * bootstrap methods responsible for linking the lambda factories are called lambda meta-factories.
- *
- * <p>The bootstrap methods in this class take the information about the functional interface, the implementation
- * method, and the static types of the captured lambda arguments, and link a call site which, when invoked,
- * produces the lambda object.
- *
- * <p>When parameterized types are used, the instantiated type of the functional interface method may be different
- * from that in the functional interface. For example, consider
- * {@code interface I<T> { int m(T x); }} if this functional interface type is used in a lambda
- * {@code I<Byte>; v = ...}, we need both the actual functional interface method which has the signature
- * {@code (Object)int} and the erased instantiated type of the functional interface method (or simply
- * <I>instantiated method type</I>), which has signature
- * {@code (Byte)int}.
+ * <p>Methods to facilitate the creation of simple "function objects" that
+ * implement one or more interfaces by delegation to a provided {@link MethodHandle},
+ * possibly after type adaptation and partial evaluation of arguments. These
+ * methods are typically used as <em>bootstrap methods</em> for {@code invokedynamic}
+ * call sites, to support the <em>lambda expression</em> and <em>method
+ * reference expression</em> features of the Java Programming Language.
*
- * <p>The argument list of the implementation method and the argument list of the functional interface method(s)
- * may differ in several ways. The implementation methods may have additional arguments to accommodate arguments
- * captured by the lambda expression; there may also be differences resulting from permitted adaptations of
- * arguments, such as casting, boxing, unboxing, and primitive widening. They may also differ because of var-args,
- * but this is expected to be handled by the compiler.
- *
- * <p>Invokedynamic call sites have two argument lists: a static argument list and a dynamic argument list. The
- * static argument list lives in the constant pool; the dynamic argument list lives on the operand stack at
- * invocation time. The bootstrap method has access to the entire static argument list (which in this case,
- * contains method handles describing the implementation method and the canonical functional interface method),
- * as well as a method signature describing the number and static types (but not the values) of the dynamic
- * arguments, and the static return type of the invokedynamic site.
+ * <p>Indirect access to the behavior specified by the provided {@code MethodHandle}
+ * proceeds in order through three phases:
+ * <ul>
+ * <li><em>Linkage</em> occurs when the methods in this class are invoked.
+ * They take as arguments an interface to be implemented (typically a
+ * <em>functional interface</em>, one with a single abstract method), a
+ * name and signature of a method from that interface to be implemented, a
+ * method handle describing the desired implementation behavior
+ * for that method, and possibly other additional metadata, and produce a
+ * {@link CallSite} whose target can be used to create suitable function
+ * objects. Linkage may involve dynamically loading a new class that
+ * implements the target interface. The {@code CallSite} can be considered a
+ * "factory" for function objects and so these linkage methods are referred
+ * to as "metafactories".</li>
*
- * <p>The implementation method is described with a method handle. In theory, any method handle could be used.
- * Currently supported are method handles representing invocation of virtual, interface, constructor and static
- * methods.
+ * <li><em>Capture</em> occurs when the {@code CallSite}'s target is
+ * invoked, typically through an {@code invokedynamic} call site,
+ * producing a function object. This may occur many times for
+ * a single factory {@code CallSite}. Capture may involve allocation of a
+ * new function object, or may return an existing function object. The
+ * behavior {@code MethodHandle} may have additional parameters beyond those
+ * of the specified interface method; these are referred to as <em>captured
+ * parameters</em>, which must be provided as arguments to the
+ * {@code CallSite} target, and which may be early-bound to the behavior
+ * {@code MethodHandle}. The number of captured parameters and their types
+ * are determined during linkage.</li>
*
- * <p>Assume:
- * <ul>
- * <li>the functional interface method has N arguments, of types (U1, U2, ... Un) and return type Ru</li>
- * <li>then the instantiated method type also has N arguments, of types (T1, T2, ... Tn) and return type Rt</li>
- * <li>the implementation method has M arguments, of types (A1..Am) and return type Ra,</li>
- * <li>the dynamic argument list has K arguments of types (D1..Dk), and the invokedynamic return site has
- * type Rd</li>
- * <li>the functional interface type is F</li>
+ * <li><em>Invocation</em> occurs when an implemented interface method
+ * is invoked on a function object. This may occur many times for a single
+ * function object. The method referenced by the behavior {@code MethodHandle}
+ * is invoked with the captured arguments and any additional arguments
+ * provided on invocation, as if by {@link MethodHandle#invoke(Object...)}.</li>
* </ul>
*
- * <p>The following signature invariants must hold:
+ * <p>It is sometimes useful to restrict the set of inputs or results permitted
+ * at invocation. For example, when the generic interface {@code Predicate<T>}
+ * is parameterized as {@code Predicate<String>}, the input must be a
+ * {@code String}, even though the method to implement allows any {@code Object}.
+ * At linkage time, an additional {@link MethodType} parameter describes the
+ * "instantiated" method type; on invocation, the arguments and eventual result
+ * are checked against this {@code MethodType}.
+ *
+ * <p>This class provides two forms of linkage methods: a standard version
+ * ({@link #metafactory(MethodHandles.Lookup, String, MethodType, MethodType, MethodHandle, MethodType)})
+ * using an optimized protocol, and an alternate version
+ * {@link #altMetafactory(MethodHandles.Lookup, String, MethodType, Object...)}).
+ * The alternate version is a generalization of the standard version, providing
+ * additional control over the behavior of the generated function objects via
+ * flags and additional arguments. The alternate version adds the ability to
+ * manage the following attributes of function objects:
+ *
* <ul>
- * <li>Rd is a subtype of F</li>
- * <li>For i=1..N, Ti is a subtype of Ui</li>
- * <li>Either Rt and Ru are primitive and are the same type, or both are reference types and
- * Rt is a subtype of Ru</li>
- * <li>If the implementation method is a static method:
- * <ul>
- * <li>K + N = M</li>
- * <li>For i=1..K, Di = Ai</li>
- * <li>For i=1..N, Ti is adaptable to Aj, where j=i+k</li>
- * </ul></li>
- * <li>If the implementation method is an instance method:
- * <ul>
- * <li>K + N = M + 1</li>
- * <li>D1 must be a subtype of the enclosing class for the implementation method</li>
- * <li>For i=2..K, Di = Aj, where j=i-1</li>
- * <li>For i=1..N, Ti is adaptable to Aj, where j=i+k-1</li>
- * </ul></li>
- * <li>The return type Rt is void, or the return type Ra is not void and is adaptable to Rt</li>
+ * <li><em>Bridging.</em> It is sometimes useful to implement multiple
+ * variations of the method signature, involving argument or return type
+ * adaptation. This occurs when multiple distinct VM signatures for a method
+ * are logically considered to be the same method by the language. The
+ * flag {@code FLAG_BRIDGES} indicates that a list of additional
+ * {@code MethodType}s will be provided, each of which will be implemented
+ * by the resulting function object. These methods will share the same
+ * name and instantiated type.</li>
+ *
+ * <li><em>Multiple interfaces.</em> If needed, more than one interface
+ * can be implemented by the function object. (These additional interfaces
+ * are typically marker interfaces with no methods.) The flag {@code FLAG_MARKERS}
+ * indicates that a list of additional interfaces will be provided, each of
+ * which should be implemented by the resulting function object.</li>
+ *
+ * <li><em>Serializability.</em> The generated function objects do not
+ * generally support serialization. If desired, {@code FLAG_SERIALIZABLE}
+ * can be used to indicate that the function objects should be serializable.
+ * Serializable function objects will use, as their serialized form,
+ * instances of the class {@code SerializedLambda}, which requires additional
+ * assistance from the capturing class (the class described by the
+ * {@link MethodHandles.Lookup} parameter {@code caller}); see
+ * {@link SerializedLambda} for details.</li>
* </ul>
*
- * <p>Note that the potentially parameterized implementation return type provides the value for the SAM. Whereas
- * the completely known instantiated return type is adapted to the implementation arguments. Because the
- * instantiated type of the implementation method is not available, the adaptability of return types cannot be
- * checked as precisely at link-time as the arguments can be checked. Thus a loose version of link-time checking is
- * done on return type, while a strict version is applied to arguments.
+ * <p>Assume the linkage arguments are as follows:
+ * <ul>
+ * <li>{@code invokedType} (describing the {@code CallSite} signature) has
+ * K parameters of types (D1..Dk) and return type Rd;</li>
+ * <li>{@code samMethodType} (describing the implemented method type) has N
+ * parameters, of types (U1..Un) and return type Ru;</li>
+ * <li>{@code implMethod} (the {@code MethodHandle} providing the
+ * implementation has M parameters, of types (A1..Am) and return type Ra
+ * (if the method describes an instance method, the method type of this
+ * method handle already includes an extra first argument corresponding to
+ * the receiver);</li>
+ * <li>{@code instantiatedMethodType} (allowing restrictions on invocation)
+ * has N parameters, of types (T1..Tn) and return type Rt.</li>
+ * </ul>
+ *
+ * <p>Then the following linkage invariants must hold:
+ * <ul>
+ * <li>Rd is an interface</li>
+ * <li>{@code implMethod} is a <em>direct method handle</em></li>
+ * <li>{@code samMethodType} and {@code instantiatedMethodType} have the same
+ * arity N, and for i=1..N, Ti and Ui are the same type, or Ti and Ui are
+ * both reference types and Ti is a subtype of Ui</li>
+ * <li>Either Rt and Ru are the same type, or both are reference types and
+ * Rt is a subtype of Ru</li>
+ * <li>K + N = M</li>
+ * <li>For i=1..K, Di = Ai</li>
+ * <li>For i=1..N, Ti is adaptable to Aj, where j=i+k</li>
+ * <li>The return type Rt is void, or the return type Ra is not void and is
+ * adaptable to Rt</li>
+ * </ul>
+ *
+ * <p>Further, at capture time, if {@code implMethod} corresponds to an instance
+ * method, and there are any capture arguments ({@code K > 0}), then the first
+ * capture argument (corresponding to the receiver) must be non-null.
*
* <p>A type Q is considered adaptable to S as follows:
* <table summary="adaptable types">
- * <tr><th>Q</th><th>S</th><th>Link-time checks</th><th>Capture-time checks</th></tr>
+ * <tr><th>Q</th><th>S</th><th>Link-time checks</th><th>Invocation-time checks</th></tr>
* <tr>
* <td>Primitive</td><td>Primitive</td>
* <td>Q can be converted to S via a primitive widening conversion</td>
@@ -123,27 +163,59 @@
* </tr>
* <tr>
* <td>Reference</td><td>Primitive</td>
- * <td>strict: Q is a primitive wrapper and Primitive(Q) can be widened to S
- * <br>loose: If Q is a primitive wrapper, check that Primitive(Q) can be widened to S</td>
- * <td>If Q is not a primitive wrapper, cast Q to the base Wrapper(S); for example Number for numeric types</td>
+ * <td>for parameter types: Q is a primitive wrapper and Primitive(Q)
+ * can be widened to S
+ * <br>for return types: If Q is a primitive wrapper, check that
+ * Primitive(Q) can be widened to S</td>
+ * <td>If Q is not a primitive wrapper, cast Q to the base Wrapper(S);
+ * for example Number for numeric types</td>
* </tr>
* <tr>
* <td>Reference</td><td>Reference</td>
- * <td>strict: S is a supertype of Q
- * <br>loose: none</td>
+ * <td>for parameter types: S is a supertype of Q
+ * <br>for return types: none</td>
* <td>Cast from Q to S</td>
* </tr>
* </table>
*
- * The default bootstrap ({@link #metafactory}) represents the common cases and uses an optimized protocol.
- * Alternate bootstraps (e.g., {@link #altMetafactory}) exist to support uncommon cases such as serialization
- * or additional marker superinterfaces.
+ * @apiNote These linkage methods are designed to support the evaluation
+ * of <em>lambda expressions</em> and <em>method references</em> in the Java
+ * Language. For every lambda expressions or method reference in the source code,
+ * there is a target type which is a functional interface. Evaluating a lambda
+ * expression produces an object of its target type. The recommended mechanism
+ * for evaluating lambda expressions is to desugar the lambda body to a method,
+ * invoke an invokedynamic call site whose static argument list describes the
+ * sole method of the functional interface and the desugared implementation
+ * method, and returns an object (the lambda object) that implements the target
+ * type. (For method references, the implementation method is simply the
+ * referenced method; no desugaring is needed.)
*
+ * <p>The argument list of the implementation method and the argument list of
+ * the interface method(s) may differ in several ways. The implementation
+ * methods may have additional arguments to accommodate arguments captured by
+ * the lambda expression; there may also be differences resulting from permitted
+ * adaptations of arguments, such as casting, boxing, unboxing, and primitive
+ * widening. (Varargs adaptations are not handled by the metafactories; these are
+ * expected to be handled by the caller.)
+ *
+ * <p>Invokedynamic call sites have two argument lists: a static argument list
+ * and a dynamic argument list. The static argument list is stored in the
+ * constant pool; the dynamic argument is pushed on the operand stack at capture
+ * time. The bootstrap method has access to the entire static argument list
+ * (which in this case, includes information describing the implementation method,
+ * the target interface, and the target interface method(s)), as well as a
+ * method signature describing the number and static types (but not the values)
+ * of the dynamic arguments and the static return type of the invokedynamic site.
+ *
+ * @implNote The implementation method is described with a method handle. In
+ * theory, any method handle could be used. Currently supported are direct method
+ * handles representing invocation of virtual, interface, constructor and static
+ * methods.
*/
public class LambdaMetafactory {
- /** Flag for alternate metafactories indicating the lambda object is
- * must to be serializable */
+ /** Flag for alternate metafactories indicating the lambda object
+ * must be serializable */
public static final int FLAG_SERIALIZABLE = 1 << 0;
/**
@@ -163,41 +235,58 @@
private static final MethodType[] EMPTY_MT_ARRAY = new MethodType[0];
/**
- * Standard meta-factory for conversion of lambda expressions or method
- * references to functional interfaces.
+ * Facilitates the creation of simple "function objects" that implement one
+ * or more interfaces by delegation to a provided {@link MethodHandle},
+ * after appropriate type adaptation and partial evaluation of arguments.
+ * Typically used as a <em>bootstrap method</em> for {@code invokedynamic}
+ * call sites, to support the <em>lambda expression</em> and <em>method
+ * reference expression</em> features of the Java Programming Language.
+ *
+ * <p>This is the standard, streamlined metafactory; additional flexibility
+ * is provided by {@link #altMetafactory(MethodHandles.Lookup, String, MethodType, Object...)}.
+ * A general description of the behavior of this method is provided
+ * {@link LambdaMetafactory above}.
+ *
+ * <p>When the target of the {@code CallSite} returned from this method is
+ * invoked, the resulting function objects are instances of a class which
+ * implements the interface named by the return type of {@code invokedType},
+ * declares a method with the name given by {@code invokedName} and the
+ * signature given by {@code samMethodType}. It may also override additional
+ * methods from {@code Object}.
*
- * @param caller Stacked automatically by VM; represents a lookup context
- * with the accessibility privileges of the caller.
- * @param invokedName Stacked automatically by VM; the name of the invoked
- * method as it appears at the call site.
- * Used as the name of the functional interface method
- * to which the lambda or method reference is being
- * converted.
- * @param invokedType Stacked automatically by VM; the signature of the
- * invoked method, which includes the expected static
- * type of the returned lambda object, and the static
- * types of the captured arguments for the lambda.
+ * @param caller Represents a lookup context with the accessibility
+ * privileges of the caller. When used with {@code invokedynamic},
+ * this is stacked automatically by the VM.
+ * @param invokedName The name of the method to implement. When used with
+ * {@code invokedynamic}, this is provided by the
+ * {@code NameAndType} of the {@code InvokeDynamic}
+ * structure and is stacked automatically by the VM.
+ * @param invokedType The expected signature of the {@code CallSite}. The
+ * parameter types represent the types of capture variables;
+ * the return type is the interface to implement. When
+ * used with {@code invokedynamic}, this is provided by
+ * the {@code NameAndType} of the {@code InvokeDynamic}
+ * structure and is stacked automatically by the VM.
* In the event that the implementation method is an
- * instance method, the first argument in the invocation
- * signature will correspond to the receiver.
- * @param samMethodType MethodType of the method in the functional interface
- * to which the lambda or method reference is being
- * converted, represented as a MethodType.
+ * instance method and this signature has any parameters,
+ * the first parameter in the invocation signature must
+ * correspond to the receiver.
+ * @param samMethodType Signature and return type of method to be implemented
+ * by the function object.
* @param implMethod A direct method handle describing the implementation
* method which should be called (with suitable adaptation
- * of argument types, return types, and adjustment for
- * captured arguments) when methods of the resulting
- * functional interface instance are invoked.
- * @param instantiatedMethodType The signature of the primary functional
- * interface method after type variables
- * are substituted with their instantiation
- * from the capture site.
- * @return a CallSite, which, when invoked, will return an instance of the
- * functional interface
- * @throws ReflectiveOperationException if the caller is not able to
- * reconstruct one of the method handles
- * @throws LambdaConversionException If any of the meta-factory protocol
- * invariants are violated
+ * of argument types, return types, and with captured
+ * arguments prepended to the invocation arguments) at
+ * invocation time.
+ * @param instantiatedMethodType The signature and return type that should
+ * be enforced dynamically at invocation time.
+ * This may be the same as {@code samMethodType},
+ * or may be a specialization of it.
+ * @return a CallSite whose target can be used to perform capture, generating
+ * instances of the interface named by {@code invokedType}
+ * @throws LambdaConversionException If any of the linkage invariants
+ * described {@link LambdaMetafactory above}
+ * are violated
*/
public static CallSite metafactory(MethodHandles.Lookup caller,
String invokedName,
@@ -205,7 +294,7 @@
MethodType samMethodType,
MethodHandle implMethod,
MethodType instantiatedMethodType)
- throws ReflectiveOperationException, LambdaConversionException {
+ throws LambdaConversionException {
AbstractValidatingLambdaMetafactory mf;
mf = new InnerClassLambdaMetafactory(caller, invokedType,
invokedName, samMethodType,
@@ -216,11 +305,23 @@
}
/**
- * Alternate meta-factory for conversion of lambda expressions or method
- * references to functional interfaces, which supports serialization and
- * other uncommon options.
+ * Facilitates the creation of simple "function objects" that implement one
+ * or more interfaces by delegation to a provided {@link MethodHandle},
+ * after appropriate type adaptation and partial evaluation of arguments.
+ * Typically used as a <em>bootstrap method</em> for {@code invokedynamic}
+ * call sites, to support the <em>lambda expression</em> and <em>method
+ * reference expression</em> features of the Java Programming Language.
*
- * <p>The declared argument list for this method is:
+ * <p>This is the general, more flexible metafactory; a streamlined version
+ * is provided by {@link #altMetafactory(MethodHandles.Lookup, String, MethodType, Object...)}.
+ * A general description of the behavior of this method is provided
+ * {@link LambdaMetafactory above}.
+ *
+ * <p>The argument list for this method includes three fixed parameters,
+ * corresponding to the parameters automatically stacked by the VM for the
+ * bootstrap method in an {@code invokedynamic} invocation, and an {@code Object[]}
+ * parameter that contains additional parameters. The declared argument
+ * list for this method is:
*
* <pre>{@code
* CallSite altMetafactory(MethodHandles.Lookup caller,
@@ -229,61 +330,103 @@
* Object... args)
* }</pre>
*
- * <p>but it behaves as if the argument list is as follows, where names that
- * appear in the argument list for
- * {@link #metafactory(MethodHandles.Lookup, String, MethodType, MethodType, MethodHandle, MethodType)}
- * have the same specification as in that method:
+ * <p>but it behaves as if the argument list is as follows:
*
* <pre>{@code
* CallSite altMetafactory(MethodHandles.Lookup caller,
* String invokedName,
* MethodType invokedType,
- * MethodType samMethodType
+ * MethodType samMethodType,
* MethodHandle implMethod,
* MethodType instantiatedMethodType,
* int flags,
- * int markerInterfaceCount, // IF flags has MARKERS set
- * Class... markerInterfaces // IF flags has MARKERS set
- * int bridgeCount, // IF flags has BRIDGES set
- * MethodType... bridges // IF flags has BRIDGES set
+ * int markerInterfaceCount, // IF flags has MARKERS set
+ * Class... markerInterfaces, // IF flags has MARKERS set
+ * int bridgeCount, // IF flags has BRIDGES set
+ * MethodType... bridges // IF flags has BRIDGES set
* )
* }</pre>
*
- * <p>If the flags contains {@code FLAG_SERIALIZABLE}, or one of the marker
- * interfaces extends {@link Serializable}, the metafactory will link the
- * call site to one that produces a serializable lambda. In addition to
- * the lambda instance implementing {@code Serializable}, it will have a
- * {@code writeReplace} method that returns an appropriate {@link
- * SerializedLambda}, and an appropriate {@code $deserializeLambda$}
- * method.
+ * <p>Arguments that appear in the argument list for
+ * {@link #metafactory(MethodHandles.Lookup, String, MethodType, MethodType, MethodHandle, MethodType)}
+ * have the same specification as in that method. The additional arguments
+ * are interpreted as follows:
+ * <ul>
+ * <li>{@code flags} indicates additional options; this is a bitwise
+ * OR of desired flags. Defined flags are {@link #FLAG_BRIDGES},
+ * {@link #FLAG_MARKERS}, and {@link #FLAG_SERIALIZABLE}.</li>
+ * <li>{@code markerInterfaceCount} is the number of additional interfaces
+ * the function object should implement, and is present if and only if the
+ * {@code FLAG_MARKERS} flag is set.</li>
+ * <li>{@code markerInterfaces} is a variable-length list of additional
+ * interfaces to implement, whose length equals {@code markerInterfaceCount},
+ * and is present if and only if the {@code FLAG_MARKERS} flag is set.</li>
+ * <li>{@code bridgeCount} is the number of additional method signatures
+ * the function object should implement, and is present if and only if
+ * the {@code FLAG_BRIDGES} flag is set.</li>
+ * <li>{@code bridges} is a variable-length list of additional
+ * methods signatures to implement, whose length equals {@code bridgeCount},
+ * and is present if and only if the {@code FLAG_BRIDGES} flag is set.</li>
+ * </ul>
+ *
+ * <p>Each class named by {@code markerInterfaces} is subject to the same
+ * restrictions as {@code Rd}, the return type of {@code invokedType},
+ * as described {@link LambdaMetafactory above}. Each {@code MethodType}
+ * named by {@code bridges} is subject to the same restrictions as
+ * {@code samMethodType}, as described {@link LambdaMetafactory above}.
+ *
+ * <p>When FLAG_SERIALIZABLE is set in {@code flags}, the function objects
+ * will implement {@code Serializable}, and will have a {@code writeReplace}
+ * method that returns an appropriate {@link SerializedLambda}. The
+ * {@code caller} class must have an appropriate {@code $deserializeLambda$}
+ * method, as described in {@link SerializedLambda}.
*
- * @param caller Stacked automatically by VM; represents a lookup context
- * with the accessibility privileges of the caller.
- * @param invokedName Stacked automatically by VM; the name of the invoked
- * method as it appears at the call site.
- * Used as the name of the functional interface method
- * to which the lambda or method reference is being
- * converted.
- * @param invokedType Stacked automatically by VM; the signature of the
- * invoked method, which includes the expected static
- * type of the returned lambda object, and the static
- * types of the captured arguments for the lambda.
+ * <p>When the target of the {@code CallSite} returned from this method is
+ * invoked, the resulting function objects are instances of a class with
+ * the following properties:
+ * <ul>
+ * <li>The class implements the interface named by the return type
+ * of {@code invokedType} and any interfaces named by {@code markerInterfaces}</li>
+ * <li>The class declares methods with the name given by {@code invokedName},
+ * and the signature given by {@code samMethodType} and additional signatures
+ * given by {@code bridges}</li>
+ * <li>The class may override methods from {@code Object}, and may
+ * implement methods related to serialization.</li>
+ * </ul>
+ *
+ * @param caller Represents a lookup context with the accessibility
+ * privileges of the caller. When used with {@code invokedynamic},
+ * this is stacked automatically by the VM.
+ * @param invokedName The name of the method to implement. When used with
+ * {@code invokedynamic}, this is provided by the
+ * {@code NameAndType} of the {@code InvokeDynamic}
+ * structure and is stacked automatically by the VM.
+ * @param invokedType The expected signature of the {@code CallSite}. The
+ * parameter types represent the types of capture variables;
+ * the return type is the interface to implement. When
+ * used with {@code invokedynamic}, this is provided by
+ * the {@code NameAndType} of the {@code InvokeDynamic}
+ * structure and is stacked automatically by the VM.
* In the event that the implementation method is an
- * instance method, the first argument in the invocation
- * signature will correspond to the receiver.
- * @param args flags and optional arguments, as described above.
- * @return a CallSite, which, when invoked, will return an instance of the
- * functional interface
- * @throws ReflectiveOperationException if the caller is not able to
- * reconstruct one of the method handles
- * @throws LambdaConversionException If any of the meta-factory protocol
- * invariants are violated
+ * instance method and this signature has any parameters,
+ * the first parameter in the invocation signature must
+ * correspond to the receiver.
+ * @param args An {@code Object[]} array containing the required
+ * arguments {@code samMethodType}, {@code implMethod},
+ * {@code instantiatedMethodType}, {@code flags}, and any
+ * optional arguments, as described
+ * {@link #altMetafactory(MethodHandles.Lookup, String, MethodType, Object...)} above}
+ * @return a CallSite whose target can be used to perform capture, generating
+ * instances of the interface named by {@code invokedType}
+ * @throws LambdaConversionException If any of the linkage invariants
+ * described {@link LambdaMetafactory above}
+ * are violated
*/
public static CallSite altMetafactory(MethodHandles.Lookup caller,
String invokedName,
MethodType invokedType,
Object... args)
- throws ReflectiveOperationException, LambdaConversionException {
+ throws LambdaConversionException {
MethodType samMethodType = (MethodType)args[0];
MethodHandle implMethod = (MethodHandle)args[1];
MethodType instantiatedMethodType = (MethodType)args[2];
@@ -308,15 +451,15 @@
else
bridges = EMPTY_MT_ARRAY;
- boolean foundSerializableSupertype = Serializable.class.isAssignableFrom(invokedType.returnType());
- for (Class<?> c : markerInterfaces)
- foundSerializableSupertype |= Serializable.class.isAssignableFrom(c);
- boolean isSerializable = ((flags & LambdaMetafactory.FLAG_SERIALIZABLE) != 0)
- || foundSerializableSupertype;
-
- if (isSerializable && !foundSerializableSupertype) {
- markerInterfaces = Arrays.copyOf(markerInterfaces, markerInterfaces.length + 1);
- markerInterfaces[markerInterfaces.length-1] = Serializable.class;
+ boolean isSerializable = ((flags & FLAG_SERIALIZABLE) != 0);
+ if (isSerializable) {
+ boolean foundSerializableSupertype = Serializable.class.isAssignableFrom(invokedType.returnType());
+ for (Class<?> c : markerInterfaces)
+ foundSerializableSupertype |= Serializable.class.isAssignableFrom(c);
+ if (!foundSerializableSupertype) {
+ markerInterfaces = Arrays.copyOf(markerInterfaces, markerInterfaces.length + 1);
+ markerInterfaces[markerInterfaces.length-1] = Serializable.class;
+ }
}
AbstractValidatingLambdaMetafactory mf