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	/*
	* Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
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	*/
	package java.lang.constant;

	import java.lang.invoke.CallSite;
	import java.lang.invoke.MethodHandle;
	import java.lang.invoke.MethodHandles;
	import java.util.Arrays;
	import java.util.Objects;
	import java.util.stream.Stream;

	import static java.lang.constant.ConstantDescs.CD_String;
	import static java.lang.constant.ConstantUtils.EMPTY_CONSTANTDESC;
	import static java.lang.constant.ConstantUtils.validateMemberName;
	import static java.util.Objects.requireNonNull;
	import static java.util.stream.Collectors.joining;

	/**
	* A <a href="package-summary.html#nominal">nominal descriptor</a> for an
	* {@code invokedynamic} call site.
	*
	* <p>Concrete subtypes of {@linkplain DynamicCallSiteDesc} should be immutable
	* and their behavior should not rely on object identity.
	*
	* @since 12
	*/
	public class DynamicCallSiteDesc {

	private final DirectMethodHandleDesc bootstrapMethod;
	private final ConstantDesc[] bootstrapArgs;
	private final String invocationName;
	private final MethodTypeDesc invocationType;

	/**
	* Creates a nominal descriptor for an {@code invokedynamic} call site.
	*
	* @param bootstrapMethod a {@link DirectMethodHandleDesc} describing the
	* bootstrap method for the {@code invokedynamic}
	* @param invocationName The unqualified name that would appear in the {@code NameAndType}
	* operand of the {@code invokedynamic}
	* @param invocationType a {@link MethodTypeDesc} describing the invocation
	* type that would appear in the {@code NameAndType}
	* operand of the {@code invokedynamic}
	* @param bootstrapArgs {@link ConstantDesc}s describing the static arguments
	* to the bootstrap, that would appear in the
	* {@code BootstrapMethods} attribute
	* @throws NullPointerException if any parameter or its contents are {@code null}
	* @throws IllegalArgumentException if the invocation name has the incorrect
	* format
	* @jvms 4.2.2 Unqualified Names
	*/
	private DynamicCallSiteDesc(DirectMethodHandleDesc bootstrapMethod,
	String invocationName,
	MethodTypeDesc invocationType,
	ConstantDesc[] bootstrapArgs) {
	this.invocationName = validateMemberName(requireNonNull(invocationName), true);
	this.invocationType = requireNonNull(invocationType);
	this.bootstrapMethod = requireNonNull(bootstrapMethod);
	this.bootstrapArgs = requireNonNull(bootstrapArgs.clone());
	for (int i = 0; i < this.bootstrapArgs.length; i++) {
	requireNonNull(this.bootstrapArgs[i]);
	}
	if (invocationName.length() == 0)
	throw new IllegalArgumentException("Illegal invocation name: " + invocationName);
	}

	/**
	* Creates a nominal descriptor for an {@code invokedynamic} call site.
	*
	* @param bootstrapMethod a {@link DirectMethodHandleDesc} describing the
	* bootstrap method for the {@code invokedynamic}
	* @param invocationName The unqualified name that would appear in the {@code NameAndType}
	* operand of the {@code invokedynamic}
	* @param invocationType a {@link MethodTypeDesc} describing the invocation
	* type that would appear in the {@code NameAndType}
	* operand of the {@code invokedynamic}
	* @param bootstrapArgs {@link ConstantDesc}s describing the static arguments
	* to the bootstrap, that would appear in the
	* {@code BootstrapMethods} attribute
	* @return the nominal descriptor
	* @throws NullPointerException if any parameter or its contents are {@code null}
	* @throws IllegalArgumentException if the invocation name has the incorrect
	* format
	* @jvms 4.2.2 Unqualified Names
	*/
	public static DynamicCallSiteDesc of(DirectMethodHandleDesc bootstrapMethod,
	String invocationName,
	MethodTypeDesc invocationType,
	ConstantDesc... bootstrapArgs) {
	return new DynamicCallSiteDesc(bootstrapMethod, invocationName, invocationType, bootstrapArgs);
	}

	/**
	* Creates a nominal descriptor for an {@code invokedynamic} call site whose
	* bootstrap method has no static arguments.
	*
	* @param bootstrapMethod The bootstrap method for the {@code invokedynamic}
	* @param invocationName The invocationName that would appear in the
	* {@code NameAndType} operand of the {@code invokedynamic}
	* @param invocationType The invocation invocationType that would appear
	* in the {@code NameAndType} operand of the {@code invokedynamic}
	* @return the nominal descriptor
	* @throws NullPointerException if any parameter is null
	* @throws IllegalArgumentException if the invocation name has the incorrect
	* format
	*/
	public static DynamicCallSiteDesc of(DirectMethodHandleDesc bootstrapMethod,
	String invocationName,
	MethodTypeDesc invocationType) {
	return new DynamicCallSiteDesc(bootstrapMethod, invocationName, invocationType, EMPTY_CONSTANTDESC);
	}

	/**
	* Creates a nominal descriptor for an {@code invokedynamic} call site whose
	* bootstrap method has no static arguments and for which the name parameter
	* is {@link ConstantDescs#DEFAULT_NAME}.
	*
	* @param bootstrapMethod a {@link DirectMethodHandleDesc} describing the
	* bootstrap method for the {@code invokedynamic}
	* @param invocationType a {@link MethodTypeDesc} describing the invocation
	* type that would appear in the {@code NameAndType}
	* operand of the {@code invokedynamic}
	* @return the nominal descriptor
	* @throws NullPointerException if any parameter is null
	*/
	public static DynamicCallSiteDesc of(DirectMethodHandleDesc bootstrapMethod,
	MethodTypeDesc invocationType) {
	return of(bootstrapMethod, ConstantDescs.DEFAULT_NAME, invocationType);
	}

	/**
	* Returns a nominal descriptor for an {@code invokedynamic} call site whose
	* bootstrap method, name, and invocation type are the same as this one, but
	* with the specified bootstrap arguments.
	*
	* @param bootstrapArgs {@link ConstantDesc}s describing the static arguments
	* to the bootstrap, that would appear in the
	* {@code BootstrapMethods} attribute
	* @return the nominal descriptor
	* @throws NullPointerException if the argument or its contents are {@code null}
	*/
	public DynamicCallSiteDesc withArgs(ConstantDesc... bootstrapArgs) {
	return new DynamicCallSiteDesc(bootstrapMethod, invocationName, invocationType, bootstrapArgs);
	}

	/**
	* Returns a nominal descriptor for an {@code invokedynamic} call site whose
	* bootstrap and bootstrap arguments are the same as this one, but with the
	* specified invocationName and invocation invocationType
	*
	* @param invocationName The unqualified name that would appear in the {@code NameAndType}
	* operand of the {@code invokedynamic}
	* @param invocationType a {@link MethodTypeDesc} describing the invocation
	* type that would appear in the {@code NameAndType}
	* operand of the {@code invokedynamic}
	* @return the nominal descriptor
	* @throws NullPointerException if any parameter is null
	* @throws IllegalArgumentException if the invocation name has the incorrect
	* format
	* @jvms 4.2.2 Unqualified Names
	*/
	public DynamicCallSiteDesc withNameAndType(String invocationName,
	MethodTypeDesc invocationType) {
	return new DynamicCallSiteDesc(bootstrapMethod, invocationName, invocationType, bootstrapArgs);
	}

	/**
	* Returns the invocation name that would appear in the {@code NameAndType}
	* operand of the {@code invokedynamic}.
	*
	* @return the invocation name
	*/
	public String invocationName() {
	return invocationName;
	}

	/**
	* Returns a {@link MethodTypeDesc} describing the invocation type that
	* would appear in the {@code NameAndType} operand of the {@code invokedynamic}.
	*
	* @return the invocation type
	*/
	public MethodTypeDesc invocationType() {
	return invocationType;
	}

	/**
	* Returns a {@link MethodHandleDesc} describing the bootstrap method for
	* the {@code invokedynamic}.
	*
	* @return the bootstrap method for the {@code invokedynamic}
	*/
	public MethodHandleDesc bootstrapMethod() { return bootstrapMethod; }

	/**
	* Returns {@link ConstantDesc}s describing the bootstrap arguments for the
	* {@code invokedynamic}. The returned array is always non-null. A zero
	* length array is returned if this {@linkplain DynamicCallSiteDesc} has no
	* bootstrap arguments.
	*
	* @return the bootstrap arguments for the {@code invokedynamic}
	*/
	public ConstantDesc[] bootstrapArgs() { return bootstrapArgs.clone(); }

	/**
	* Reflectively invokes the bootstrap method with the specified arguments,
	* and return the resulting {@link CallSite}
	*
	* @param lookup The {@link MethodHandles.Lookup} used to resolve class names
	* @return the {@link CallSite}
	* @throws Throwable if any exception is thrown by the bootstrap method
	*/
	public CallSite resolveCallSiteDesc(MethodHandles.Lookup lookup) throws Throwable {
	assert bootstrapMethod.invocationType().parameterType(1).equals(CD_String);
	MethodHandle bsm = (MethodHandle) bootstrapMethod.resolveConstantDesc(lookup);
	Object[] args = new Object[bootstrapArgs.length + 3];
	args[0] = lookup;
	args[1] = invocationName;
	args[2] = invocationType.resolveConstantDesc(lookup);
	System.arraycopy(bootstrapArgs, 0, args, 3, bootstrapArgs.length);
	return (CallSite) bsm.invokeWithArguments(args);
	}

	/**
	* Compares the specified object with this descriptor for equality. Returns
	* {@code true} if and only if the specified object is also a
	* {@linkplain DynamicCallSiteDesc}, and both descriptors have equal
	* bootstrap methods, bootstrap argument lists, invocation name, and
	* invocation type.
	*
	* @param o the {@code DynamicCallSiteDesc} to compare to this
	* {@code DynamicCallSiteDesc}
	* @return {@code true} if the specified {@code DynamicCallSiteDesc}
	* is equal to this {@code DynamicCallSiteDesc}.
	*/
	@Override
	public final boolean equals(Object o) {
	if (this == o) return true;
	if (o == null \|\| getClass() != o.getClass()) return false;
	DynamicCallSiteDesc specifier = (DynamicCallSiteDesc) o;
	return Objects.equals(bootstrapMethod, specifier.bootstrapMethod) &&
	Arrays.equals(bootstrapArgs, specifier.bootstrapArgs) &&
	Objects.equals(invocationName, specifier.invocationName) &&
	Objects.equals(invocationType, specifier.invocationType);
	}

	@Override
	public final int hashCode() {
	int result = Objects.hash(bootstrapMethod, invocationName, invocationType);
	result = 31 * result + Arrays.hashCode(bootstrapArgs);
	return result;
	}

	/**
	* Returns a compact textual description of this call site description,
	* including the bootstrap method, the invocation name and type, and
	* the static bootstrap arguments.
	*
	* @return A compact textual description of this call site descriptor
	*/
	@Override
	public String toString() {
	return String.format("DynamicCallSiteDesc[%s::%s(%s%s):%s]",
	bootstrapMethod.owner().displayName(),
	bootstrapMethod.methodName(),
	invocationName.equals(ConstantDescs.DEFAULT_NAME) ? "" : invocationName + "/",
	Stream.of(bootstrapArgs).map(Object::toString).collect(joining(",")),
	invocationType.displayDescriptor());
	}
	}

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