Sumisho Computer Systems Corporation

Curl Corporation

David A Kranz

Robert H Halstead, Jr

Stephen A Ward

Christopher J Terman

Mathew J Hostetter

Donald T Davis, Jr

Elizabeth A Martin

Benjamin R Harrison

Murray S Mazer

Spiro Michaylov

Tom Lyons

Carl A Soeder

A licensing system and method for deploying digital content is provided. A client system can download the digital content from the server and, if a valid license for the content is also found on the server, software may be permitted to run digital content. The license is stored in a location that is separate from the content. The license can be located using the URL address of the content. The system can locate the license on the server and determine whether the license covers the content. Content that is covered by the license can be processed and rendered. The content can be any form of digital media, such as a computer application.

URL system and method for licensing content

Mobile code, such as an applet, is permitted to create a network connection with a content server on a network, without restricting the applet only to connections from the computer from which it was downloaded. This is achieved in accordance with the principles of the present invention by using network restriction software in the execution engine or runtime system under which the applet executes. When the applet attempts to create a network connection to a content server, the network restriction software checks a name file on the content server for the presence of an entry whose name corresponds to the name of the computer from which the applet was downloaded. If such an entry is present, then the network restriction software permits the network connection between the applet and the content server to be created. If not, the applet may not create a network connection with the content server.

System and method for specifying access to resources in a mobile code system

A class includes fields to support values of properties in preallocated memory space and an option data structure which supports, in instances of the class, references to option values without preallocation of memory space. The field and option values are accessed in an instance object of the class using expressions of the same syntactic form. During compilation, the compiler checks the type of an option value against a type description within the option data structure. During compilation, a method call to an object is encoded without regard to the form of the option data structure. When an option value is changed, a change handler identified by an option binding of the data structure is processed. That option binding may be located by first searching a mapping data structure for a previously computed mapping to the option binding or by computing the mapping to the option binding.

System and method supporting property values as options

To support values of properties, a class includes fields to support values in preallocated memory space and with an option data structure which supports, in instances of the class, references to option values without preallocation of memory space. The field and option values are accessed in an instance object of the class using expressions of the same syntactic form. During compilation, the compiler checks the type of an option value against a type description within the option data structure. Different classes may support different forms of data structures such as a linked list or a hash table. During compilation, a method call to an object is encoded without regard to the form of the option data structure. An option value may be set in an option data structure from an initialization expression which includes the name of the option value and, as an argument, the option value.

System and method supporting type checking of options

To support values of properties, a class includes fields to support values in preallocated memory space and with an option data structure which supports, in instances of the class, references to option values without preallocation of memory space. If a value has not been set for an instance object, a get operation results in getting of the default value for the class. Different classes may support different forms of data structures such as a linked list or a hash table. When an option value is changed, a change handler identified by an option binding of the data structure is processed. That option binding may be located by first searching a mapping data structure for a previously computed mapping to the option binding or by computing the mapping to the option binding. Nonlocal option values may be applied to plural objects in a nonlocal option hierarchy such as a graphical hierarchy.

System and method supporting mapping of option bindings

Template-generated classes in program code are compiled efficiently through a process of lazy compilation resulting in improved compilation times. Lazy compilation includes the generation of objects representing a class template and a template-generated class as well as the selective compilation of class methods that are invoked in the program code. Code sharing is a further enhancement for increasing compilation speed by providing a system and method for sharing executable object code for compatible methods among different classes generated from the same class template.

Lazy compilation of template-generated classes in dynamic compilation execution environments

A system and methods are disclosed that permit mobile code, such as an applet, to create a network connection with a content server on a network, without exposing the client computer that is running the applet, or other computers with which the client computer may communicate, to a DNS spoofing attack. This is achieved in accordance with the principles of the present invention by using network restriction software in the execution engine or runtime system under which the applet executes. When the applet attempts to create a network connection to a content server, the network restriction software checks a 'name directory' on the content server for the presence of an entry whose name corresponds to the name of the computer from which the applet was downloaded. If such an entry is present, then the network restriction software permits the network connection between the applet and the content server to be created. If not, the applet may not create a network connection with the content server. Additionally, address checks may be applied to assist in preventing DNS spoofing attacks from succeeding.

System and methods for securely permitting mobile code to access resources over a network

To support values of properties, a class includes fields to support values in preallocated memory space and with an option data structure which supports, in instances of the class, references to option values without preallocation of memory space. The field and option values are accessed in an instance object of the class using expressions of the same syntactic form. During compilation, the compiler checks the type of an option value against a type description within the option data structure. If a value has not been set for an instance object, a get operation results in getting of the default value for the class. Different classes may support different forms of data structures such as a linked list or a hash table. During compilation, a method call to an object is encoded without regard to the form of the option data structure. When an option value is changed, a change handler identified by an option binding of the data structure is processed. That option binding may be located by first searching a mapping data structure for a previously computed mapping to the option binding or by computing the mapping to the option binding. An option value may be set in an option data structure from an initialization expression which includes the name of the option value and, as an argument, the option value. Nonlocal option values may be applied to plural objects in a nonlocal option hierarchy such as a graphical hierarchy.

System and method supporting nonlocal values

Persistent data storage for client computer software programs is provided using a repository that enables client computer software programs to store data securely on a client computer system, subsequently retrieve that data, and optionally share the data in a controlled fashion with authorized client computer software programs. The present invention can be used by both trusted and untrusted client computer software programs that either reside locally on the client computer system or are downloaded from a server computer system. A benefit of the present invention is that it allows untrusted applets to have access to persistent storage without compromising the integrity of the client computer system. Since the present invention controls persistent storage space, not the programmer of the client computer software program, the burden of insuring storage integrity and security is removed from the programmer. In addition to basic integrity and security features, the present invention provides automatic data format conversion for client computer software programs reading/writing data in the data repository, a commit operation to force in-memory repository data to disk, and automatic expiration to delete the repository after a predetermined time period. The repository can be pre-limited to a maximum size and shared among multiple client computer software programs.

Persistent data storage for client computer software programs

The present invention provides for operations on objects in a hierarchy by partitioning the hierarchy into subhierarchies, each subhierarchy being associated with a thread interface frame. Operations of the thread interface frame are executed within threads acting on objects in the subhierarchy. When needed, the effects of an operation are stored in the thread interface frame, allowing the effects to be forwarded to another subhierarchy accessed by another thread.

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Arlington, MA, United States of America

David A Kranz