duke@1: /* ohair@158: * Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved. duke@1: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. duke@1: * duke@1: * This code is free software; you can redistribute it and/or modify it duke@1: * under the terms of the GNU General Public License version 2 only, as ohair@158: * published by the Free Software Foundation. Oracle designates this duke@1: * particular file as subject to the "Classpath" exception as provided ohair@158: * by Oracle in the LICENSE file that accompanied this code. duke@1: * duke@1: * This code is distributed in the hope that it will be useful, but WITHOUT duke@1: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or duke@1: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License duke@1: * version 2 for more details (a copy is included in the LICENSE file that duke@1: * accompanied this code). duke@1: * duke@1: * You should have received a copy of the GNU General Public License version duke@1: * 2 along with this work; if not, write to the Free Software Foundation, duke@1: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. duke@1: * ohair@158: * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA ohair@158: * or visit www.oracle.com if you need additional information or have any ohair@158: * questions. duke@1: */ duke@1: duke@1: #ifndef _IOP_IDL_ duke@1: #define _IOP_IDL_ duke@1: duke@1: #include "CORBAX.idl" duke@1: duke@1: #pragma prefix "omg.org" duke@1: duke@1: #ifndef CORBA3 duke@1: #define local duke@1: #endif duke@1: duke@1: module IOP { duke@1: // duke@1: // Standard Protocol Profile tag values duke@1: // duke@1: /** Profile ID */ duke@1: typedef unsigned long ProfileId; duke@1: duke@1: /** duke@1: * Identifies profiles that duke@1: * support the Internet Inter-ORB Protocol. The ProfileBody duke@1: * of this profile contains a CDR encapsulation of a structure duke@1: * containing addressing and object identification information used by duke@1: * IIOP. Version 1.1 of the TAG_INTERNET_IOP profile duke@1: * also includes an array of TaggedComponent objects that can duke@1: * contain additional information supporting optional IIOP features, duke@1: * ORB services such as security, and future protocol extensions. duke@1: *

duke@1: * Protocols other than IIOP (such as ESIOPs and other GIOPs) can share duke@1: * profile information (such as object identity or security duke@1: * information) with IIOP by encoding their additional profile information duke@1: * as components in the TAG_INTERNET_IOP profile. All duke@1: * TAG_INTERNET_IOP profiles support IIOP, regardless of duke@1: * whether they also support additional protocols. Interoperable duke@1: * ORBs are not required to create or understand any other profile, duke@1: * nor are they required to create or understand any of the components duke@1: * defined for other protocols that might share the duke@1: * TAG_INTERNET_IOP profile with IIOP. duke@1: *

duke@1: * The profile_data for the TAG_INTERNET_IOP duke@1: * profile is a CDR encapsulation of the IIOP.ProfileBody_1_1 duke@1: * type. duke@1: */ duke@1: const ProfileId TAG_INTERNET_IOP = 0; duke@1: duke@1: /** duke@1: * Indicates that the value encapsulated is of type duke@1: * MultipleComponentProfile. In this case, the profile duke@1: * consists of a list of protocol components, the use of which must duke@1: * be specified by the protocol using this profile. This profile may duke@1: * be used to carry IOR components. duke@1: *

duke@1: * The profile_data for the duke@1: * TAG_MULTIPLE_COMPONENTS profile is a CDR encapsulation duke@1: * of the MultipleComponentProfile type shown above. duke@1: */ duke@1: const ProfileId TAG_MULTIPLE_COMPONENTS = 1; duke@1: duke@1: /** duke@1: * Object references have at least one tagged profile. Each profile duke@1: * supports one or more protocols and encapsulates all the basic duke@1: * information the protocols it supports need to identify an object. duke@1: * Any single profile holds enough information to drive a complete duke@1: * invocation using any of the protocols it supports; the content duke@1: * and structure of those profile entries are wholly specified by duke@1: * these protocols. duke@1: */ duke@1: struct TaggedProfile { duke@1: /** The tag, represented as a profile id. */ duke@1: ProfileId tag; duke@1: duke@1: /** The associated profile data. */ duke@1: sequence profile_data; duke@1: }; duke@1: duke@1: /** duke@1: * Captures information about a object references, such as whether the duke@1: * object is null, what type it is, what protocols are supported, and what duke@1: * ORB services are available. duke@1: *

duke@1: * This data structure need not be used internally to any given ORB, duke@1: * and is not intended to be visible to application-level ORB programmers. duke@1: * It should be used only when crossing object reference domain duke@1: * boundaries, within bridges. duke@1: *

duke@1: * This data structure is designed to be efficient in typical duke@1: * single-protocol configurations, while not penalizing multiprotocol ones. duke@1: *

duke@1: * Object references have at least one tagged profile. Each profile duke@1: * supports one or more protocols and encapsulates all the basic duke@1: * information the protocols it supports need to identify an object. duke@1: * Any single profile holds enough information to drive a complete duke@1: * invocation using any of the protocols it supports; the content duke@1: * and structure of those profile entries are wholly specified by duke@1: * these protocols. A bridge between two domains may need to know the duke@1: * detailed content of the profile for those domains' profiles, duke@1: * depending on the technique it uses to bridge the domains. duke@1: *

duke@1: * Each profile has a unique numeric tag, assigned by the OMG. duke@1: * Profile tags in the range 0x80000000 through 0xffffffff are reserved duke@1: * for future use, and are not currently available for assignment. duke@1: *

duke@1: * Null object references are indicated by an empty set of profiles, duke@1: * and by a "Null" type ID (a string which contains only a single duke@1: * terminating character). A Null TypeID is the only duke@1: * mechanism that can be used to represent the type duke@1: * CORBA.Object. Type IDs may only be "Null" in any message, duke@1: * requiring the client to use existing knowledge or to consult the duke@1: * object, to determine interface types supported. The type ID duke@1: * is a Repository ID identifying the interface type, and is provided duke@1: * to allow ORBs to preserve strong typing. This identifier is agreed duke@1: * on within the bridge and, for reasons outside the scope of the duke@1: * interoperability specification, needs to have a much broader scope to duke@1: * address various problems in system evolution and maintenance. duke@1: * Type IDs support detection of type equivalence, and in conjunction duke@1: * with an Interface Repository, allow processes to reason about the duke@1: * relationship of the type of the object referred to and any other type. duke@1: *

duke@1: * The type ID, if provided by the server, indicates the most derived duke@1: * type that the server wishes to publish, at the time the reference duke@1: * is generated. The object's actual most derived type may later change duke@1: * to a more derived type. Therefore, the type ID in the IOR can only duke@1: * be interpreted by the client as a hint that the object supports at duke@1: * least the indicated interface. The client can succeed in narrowing duke@1: * the reference to the indicated interface, or to one of its base duke@1: * interfaces, based solely on the type ID in the IOR, but must not fail duke@1: * to narrow the reference without consulting the object via the duke@1: * "_is_a" or "_get_interface" pseudo-operations. duke@1: */ duke@1: struct IOR { duke@1: /** The type id, represented as a String. */ duke@1: string type_id; duke@1: duke@1: /** duke@1: * An array of tagged profiles associated with this duke@1: * object reference. duke@1: */ duke@1: sequence profiles; duke@1: }; duke@1: duke@1: /** duke@1: * Standard way of representing multicomponent profiles. duke@1: * This would be encapsulated in a TaggedProfile. duke@1: */ duke@1: typedef unsigned long ComponentId; duke@1: duke@1: /** duke@1: * TaggedComponents contained in duke@1: * TAG_INTERNET_IOP and duke@1: * TAG_MULTIPLE_COMPONENTS profiles are identified by duke@1: * unique numeric tags using a namespace distinct form that is used for duke@1: * profile tags. Component tags are assigned by the OMG. duke@1: *

duke@1: * Specifications of components must include the following information: duke@1: *

duke@1: * Specification of protocols must describe how the components affect duke@1: * the protocol. The following should be specified in any protocol duke@1: * definition for each TaggedComponent that the protocol uses: duke@1: * duke@1: */ duke@1: struct TaggedComponent { duke@1: /** The tag, represented as a component id. */ duke@1: ComponentId tag; duke@1: duke@1: /** The component data associated with the component id. */ duke@1: sequence component_data; duke@1: }; duke@1: duke@1: /** duke@1: * It is often useful in the real world to be able to identify the duke@1: * particular kind of ORB an object reference is coming from, to work duke@1: * around problems with that particular ORB, or exploit shared duke@1: * efficiencies. duke@1: *

duke@1: * The TAG_ORB_TYPE component has an associated value of duke@1: * type unsigned long (Java long), encoded as a CDR encapsulation, duke@1: * designating an ORB type ID allocated by the OMG for the ORB type of the duke@1: * originating ORB. Anyone may register any ORB types by submitting duke@1: * a short (one-paragraph) description of the ORB type to the OMG, duke@1: * and will receive a new ORB type ID in return. A list of ORB type duke@1: * descriptions and values will be made available on the OMG web server. duke@1: *

duke@1: * The TAG_ORB_TYPE component can appear at most once in duke@1: * any IOR profile. For profiles supporting IIOP 1.1 or greater, it duke@1: * is optionally present. duke@1: */ duke@1: const ComponentId TAG_ORB_TYPE = 0 ; duke@1: duke@1: /** duke@1: * The code set component of the IOR multi-component profile structure duke@1: * contains: duke@1: *

duke@1: * Both char and wchar conversion code sets are listed in order of duke@1: * preference. duke@1: */ duke@1: const ComponentId TAG_CODE_SETS = 1 ; duke@1: duke@1: /** duke@1: * A profile component containing the sequence of QoS policies exported duke@1: * with the object reference by an object adapter. duke@1: */ duke@1: const ComponentId TAG_POLICIES = 2 ; duke@1: duke@1: /** duke@1: * In cases where the same object key is used for more than one duke@1: * internet location, the following standard IOR Component is defined duke@1: * for support in IIOP version 1.2. duke@1: *

duke@1: * The TAG_ALTERNATE_IIOP_ADDRESS component has an duke@1: * associated value of type: duke@1: * duke@1: * 

duke@1:      *     struct { 
duke@1:      *         string HostID, 
duke@1:      *         short Port 
duke@1:      *     }; 
duke@1:      *
duke@1: * duke@1: * encoded as a CDR encapsulation. duke@1: *

duke@1: * Zero or more instances of the TAG_ALTERNATE_IIOP_ADDRESS duke@1: * component type may be included in a version 1.2 duke@1: * TAG_INTERNET_IOP Profile. Each of these alternative duke@1: * addresses may be used by the client orb, in addition to the host duke@1: * and port address expressed in the body of the Profile. In cases duke@1: * where one or more TAG_ALTERNATE_IIOP_ADDRESS components duke@1: * are present in a TAG_INTERNET_IOP Profile, no order of duke@1: * use is prescribed by Version 1.2 of IIOP. duke@1: */ duke@1: const ComponentId TAG_ALTERNATE_IIOP_ADDRESS = 3 ; duke@1: duke@1: /** duke@1: * Class downloading is supported for stubs, ties, values, and duke@1: * value helpers. The specification allows transmission of codebase duke@1: * information on the wire for stubs and ties, and enables usage of duke@1: * pre-existing ClassLoaders when relevant. duke@1: *

duke@1: * For values and value helpers, the codebase is transmitted after the duke@1: * value tag. For stubs and ties, the codebase is transmitted as duke@1: * the TaggedComponent TAG_JAVA_CODEBASE in the IOR duke@1: * profile, where the component_data is a CDR encapsulation duke@1: * of the codebase written as an IDL string. The codebase is a duke@1: * space-separated list of one or more URLs. duke@1: */ duke@1: const ComponentId TAG_JAVA_CODEBASE = 25 ; duke@1: duke@1: /** duke@1: * RMI-IIOP has multiple stream format versions. A server duke@1: * can specify its maximum version by including the duke@1: * TAG_RMI_CUSTOM_MAX_STREAM_FORMAT tagged component or duke@1: * rely on the default of version 1 for GIOP 1.2 and less duke@1: * and version 2 for GIOP 1.3 and higher. duke@1: * duke@1: * See Java to IDL ptc/02-01-12 1.4.11. duke@1: */ duke@1: const ComponentId TAG_RMI_CUSTOM_MAX_STREAM_FORMAT = 38 ; duke@1: duke@1: /** An array of tagged components, forming a multiple component profile. */ duke@1: typedef sequence MultipleComponentProfile; duke@1: duke@1: /** A service id, represented as an int */ duke@1: typedef unsigned long ServiceId; duke@1: duke@1: /** duke@1: * Service-specific information to be passed implicitly with requests duke@1: * and replies. Service contexts are composed of service ids and duke@1: * associated data. duke@1: */ duke@1: struct ServiceContext { duke@1: /** The service context id */ duke@1: ServiceId context_id; duke@1: duke@1: /** The data associated with this service context */ duke@1: sequence context_data; duke@1: }; duke@1: duke@1: /** An array of service contexts, forming a service context list. */ duke@1: typedef sequence ServiceContextList; duke@1: duke@1: /** duke@1: * Identifies a CDR encapsulation of the duke@1: * CosTSInteroperation.PropogationContext defined in duke@1: * CORBAservices: Common Object Services Specifications. duke@1: */ duke@1: const ServiceId TransactionService = 0; duke@1: duke@1: /** duke@1: * Identifies a CDR encapsulation of the duke@1: * CONV_FRAME.CodeSetContext defined in duke@1: * Section 13.10.2.5, "GIOP Code Set Service Context," on page 13-43. duke@1: */ duke@1: const ServiceId CodeSets = 1; duke@1: duke@1: /** duke@1: * Identifies a CDR encapsulation of the RMICustomMaxStreamFormat duke@1: * service context which contains a single byte specifying duke@1: * the client's maximum RMI-IIOP stream format version. duke@1: * duke@1: * See Java to IDL ptc/02-01-12 1.4.12. duke@1: */ duke@1: const ServiceId RMICustomMaxStreamFormat = 17 ; duke@1: duke@1: /** duke@1: * DCOM-CORBA Interworking uses three service contexts as defined in duke@1: * "DCOM-CORBA Interworking" in the "Interoperability with non-CORBA duke@1: * Systems" chapter. duke@1: *

duke@1: * ChainBypassCheck carries a CDR encapsulation of the duke@1: * struct CosBridging.ChainBypassCheck. This is carried duke@1: * only in a Request message as described in Section 20.9.1, "CORBA duke@1: * Chain Bypass," on page 20-19. duke@1: */ duke@1: const ServiceId ChainBypassCheck = 2; duke@1: duke@1: /** duke@1: * DCOM-CORBA Interworking uses three service contexts as defined in duke@1: * "DCOM-CORBA Interworking" in the "Interoperability with non-CORBA duke@1: * Systems" chapter. duke@1: *

duke@1: * ChainBypassInfo carries a CDR encapsulation of the duke@1: * struct CosBridging.ChainBypassInfo. This is carried duke@1: * only in a Reply message as described in Section 20.9.1, "CORBA Chain duke@1: * Bypass," on page 20-19. duke@1: */ duke@1: const ServiceId ChainBypassInfo = 3; duke@1: duke@1: /** duke@1: * DCOM-CORBA Interworking uses three service contexts as defined in duke@1: * "DCOM-CORBA Interworking" in the "Interoperability with non-CORBA duke@1: * Systems" chapter. duke@1: *

duke@1: * LogicalThreadId, carries a CDR encapsulation of duke@1: * the struct CosBridging.LogicalThreadId as described duke@1: * in Section 20.10, "Thread Identification," on page 20-21. duke@1: */ duke@1: const ServiceId LogicalThreadId = 4; duke@1: duke@1: /** duke@1: * Identifies a CDR encapsulation of the duke@1: * IIOP.BiDirIIOPServiceContext defined in Section 15.8, duke@1: * "Bi-Directional GIOP," on page 15-55. duke@1: */ duke@1: const ServiceId BI_DIR_IIOP = 5; duke@1: duke@1: /** duke@1: * Identifies a CDR encapsulation of the IOR of the duke@1: * SendingContext.RunTime object (see Section 5.6, "Access duke@1: * to the Sending Context Run Time," on page 5-15). duke@1: */ duke@1: const ServiceId SendingContextRunTime = 6; duke@1: duke@1: /** duke@1: * For information on INVOCATION_POLICIES refer to the duke@1: * Asynchronous Messaging specification - orbos/98-05-05. duke@1: */ duke@1: const ServiceId INVOCATION_POLICIES = 7; duke@1: duke@1: /** duke@1: * For information on FORWARDED_IDENTITY refer to the duke@1: * Firewall specification - orbos/98-05-04. duke@1: */ duke@1: const ServiceId FORWARDED_IDENTITY = 8; duke@1: duke@1: /** duke@1: * Identifies a CDR encapsulation of a marshaled instance of a duke@1: * java.lang.Throwable or one of its subclasses as described in Java duke@1: * to IDL Language Mapping, Section 1.4.8.1, "Mapping of duke@1: * UnknownExceptionInfo Service Context," on page 1-32. duke@1: */ duke@1: const ServiceId UnknownExceptionInfo = 9; duke@1: duke@1: /** duke@1: * CORBA formal/02-06-01: 13.7.1: duke@1: * ExceptionDetailMessage identifies a CDR encapsulation of a wstring, duke@1: * encoded using GIOP 1.2 with a TCS-W of UTF-16. This service context duke@1: * may be sent on Reply messages with a reply_status of SYSTEM_EXCEPTION duke@1: * or USER_EXCEPTION. The usage of this service context is defined duke@1: * by language mappings.

duke@1: * duke@1: * IDL/Java: ptc/02-01-22: 1.15.2: duke@1: * When a System Exception is marshaled, its GIOP Reply message shall duke@1: * include an associated ExceptionDetailMessage service context. The duke@1: * callee's stack trace is often very valuable debugging information but duke@1: * may contain sensitive or unwanted information. The wstring within the duke@1: * service context will therefore contain additional information relating duke@1: * to the exception, for example the result of calling either duke@1: * printStackTrace(PrintWriter) or getMessage() on the exception. When duke@1: * unmarshaling a System Exception on the client side, the wstring from duke@1: * any ExceptionDetailMessage service context shall become the Java error duke@1: * message in the unmarshaled exception object. duke@1: */ duke@1: const ServiceId ExceptionDetailMessage = 14; duke@1: duke@1: duke@1: // BEGIN part which lived in Interceptors.idl. duke@1: duke@1: /** duke@1: * An array of TaggedComponent objects. duke@1: */ duke@1: typedef sequence TaggedComponentSeq; duke@1: duke@1: /** duke@1: * The formats of IOR components and service context data used by ORB duke@1: * services are often defined as CDR encapsulations encoding instances duke@1: * of IDL defined data types. The Codec provides a mechanism duke@1: * to transfer these components between their IDL data types and their CDR duke@1: * encapsulation representations. duke@1: *

duke@1: * A Codec is obtained from the CodecFactory. duke@1: * The CodecFactory is obtained through a call to duke@1: * ORB.resolve_initial_references( "CodecFactory" ). duke@1: */ duke@1: local interface Codec { duke@1: duke@1: /** duke@1: * This exception is thrown by Codec.encode or duke@1: * Codec.encode_value when the type is invalid for the duke@1: * encoding. For example, this exception is thrown if the encoding is duke@1: * ENCODING_CDR_ENCAPS version 1.0 and a type duke@1: * that does not exist in that version, such as wstring, duke@1: * is passed to the operation. duke@1: */ duke@1: exception InvalidTypeForEncoding {}; duke@1: duke@1: /** duke@1: * This exception is thrown by Codec.decode or duke@1: * Codec.decode_value when the data in the byte array duke@1: * cannot be decoded into an Any. duke@1: */ duke@1: exception FormatMismatch {}; duke@1: duke@1: /** duke@1: * This exception is thrown by decode_value when the given duke@1: * TypeCode does not match the given byte array. duke@1: */ duke@1: exception TypeMismatch {}; duke@1: duke@1: /** duke@1: * Converts the given any into a byte array based on the encoding duke@1: * format effective for this Codec. duke@1: * duke@1: * @param data The data, in the form of an any, to be encoded into duke@1: * a byte array. duke@1: * @return A byte array containing the encoded Any. This byte array duke@1: * contains both the TypeCode and the data of the type. duke@1: * @exception InvalidTypeForEncoding thrown if the type is not valid for duke@1: * the encoding format effective for this Codec. duke@1: */ duke@1: CORBA::OctetSeq encode (in any data) duke@1: raises (InvalidTypeForEncoding); duke@1: duke@1: /** duke@1: * Decodes the given byte array into an Any based on the encoding duke@1: * format effective for this Codec. duke@1: * duke@1: * @param data The data, in the form of a byte array, to be decoded into duke@1: * an Any. duke@1: * @return An Any containing the data from the decoded byte array. duke@1: * @exception FormatMismatch is thrown if the byte array cannot be duke@1: * decoded into an Any. duke@1: */ duke@1: any decode (in CORBA::OctetSeq data) raises (FormatMismatch); duke@1: duke@1: /** duke@1: * Converts the given any into a byte array based on the encoding duke@1: * format effective for this Codec. Only the data from the Any is duke@1: * encoded, not the TypeCode. duke@1: * duke@1: * @param data The data, in the form of an Any, to be encoded into duke@1: * a byte array. duke@1: * @return A byte array containing the data from the encoded any. duke@1: * @exception InvalidTypeForEncoding thrown if the type is not valid for duke@1: * the encoding format effective for this Codec. duke@1: */ duke@1: CORBA::OctetSeq encode_value (in any data) duke@1: raises (InvalidTypeForEncoding); duke@1: duke@1: /** duke@1: * Decodes the given byte array into an Any based on the given duke@1: * TypeCode and the encoding format effective for duke@1: * this Codec. duke@1: * duke@1: * @param data The data, in the form of a byte array, to be decoded duke@1: * into an Any. duke@1: * @param tc The TypeCode to be used to decode the data. duke@1: * @return An Any containing the data from the decoded byte array. duke@1: * @exception FormatMismatch thrown if the byte array cannot be duke@1: * decoded into an Any. duke@1: */ duke@1: any decode_value (in CORBA::OctetSeq data, in CORBA::TypeCode tc) duke@1: raises (FormatMismatch, TypeMismatch); duke@1: }; duke@1: duke@1: /** duke@1: * Defines an encoding format of a Codec, such as duke@1: * CDR Encapsulation (ENCODING_CDR_ENCAPS). duke@1: */ duke@1: typedef short EncodingFormat; duke@1: duke@1: /** duke@1: * The CDR Encapsulation encoding. duke@1: * @see CodecFactory duke@1: */ duke@1: const EncodingFormat ENCODING_CDR_ENCAPS = 0; duke@1: duke@1: /** duke@1: * Defines the encoding format of a Codec. This class duke@1: * details the encoding format, such as CDR Encapsulation encoding, and duke@1: * the major and minor versions of that format. duke@1: *

duke@1: * The encodings currently supported are: duke@1: *

duke@1: * Vendors are free to support additional encodings. duke@1: * duke@1: * @see ENCODING_CDR_ENCAPS duke@1: */ duke@1: struct Encoding { duke@1: /** duke@1: * The encoding format. duke@1: */ duke@1: EncodingFormat format; duke@1: duke@1: /** duke@1: * The major version of this Encoding format. duke@1: */ duke@1: octet major_version; duke@1: duke@1: /** duke@1: * The minor version of this Encoding format. duke@1: */ duke@1: octet minor_version; duke@1: }; duke@1: duke@1: /** duke@1: * Codecs are obtained from the CodecFactory. duke@1: * The CodecFactory is obtained through a call to duke@1: * ORB.resolve_initial_references( "CodecFactory" ). duke@1: */ duke@1: local interface CodecFactory { duke@1: /** duke@1: * This exception is thrown by CodecFactory.create_codec when duke@1: * the factory cannot create a Codec for a given encoding. duke@1: */ duke@1: exception UnknownEncoding {}; duke@1: duke@1: /** duke@1: * Create a Codec of the given encoding. duke@1: *

duke@1: * @param enc The encoding for which to create a Codec. duke@1: * @return A Codec obtained with the given encoding. duke@1: * @exception UnknownEncoding thrown if this factory cannot create a duke@1: * Codec of the given encoding. duke@1: */ duke@1: Codec create_codec (in Encoding enc) raises (UnknownEncoding); duke@1: }; duke@1: duke@1: // END part which lived in Interceptors.idl. duke@1: duke@1: }; duke@1: duke@1: #endif // _IOP_IDL_