com.sun.msv.scanner.dtd

Class Resolver

public class Resolver extends Object implements EntityResolver

This entity resolver class provides a number of utilities which can help managment of external parsed entities in XML. These are commonly used to hold markup declarations that are to be used as part of a Document Type Declaration (DTD), or to hold text marked up with XML.

Features include:

Subclasses can perform tasks such as supporting new URI schemes for URIs which are not URLs, such as URNs (see RFC 2396) or for accessing MIME entities which are part of a multipart/related group (see RFC 2387). They may also be used to support particular catalog syntaxes, such as the SGML/Open Catalog (SOCAT) which supports the SGML notion of "Formal Public Identifiers (FPIs).

Version: 1.3 00/02/24

Author: David Brownell Janet Koenig

Constructor Summary
Resolver()
Constructs a resolver.
Method Summary
static InputSourcecreateInputSource(String contentType, InputStream stream, boolean checkType, String scheme)
Returns an input source, using the MIME type information and URL scheme to statically determine the correct character encoding if possible and otherwise autodetecting it.
static InputSourcecreateInputSource(URL uri, boolean checkType)
Creates an input source from a given URI.
static InputSourcecreateInputSource(File file)
Creates an input source from a given file, autodetecting the character encoding.
booleanisIgnoringMIME()
Returns true if this resolver is ignoring MIME types in the documents it returns, to work around bugs in how servers have reported the documents' MIME types.
voidregisterCatalogEntry(String publicId, String uri)
Registers the given public ID as corresponding to a particular URI, typically a local copy.
voidregisterCatalogEntry(String publicId, String resourceName, ClassLoader loader)
Registers a given public ID as corresponding to a particular Java resource in a given class loader, typically distributed with a software package.
InputSourceresolveEntity(String name, String uri)
SAX: Resolve the given entity into an input source.
voidsetIgnoringMIME(boolean value)
Tells the resolver whether to ignore MIME types in the documents it retrieves.

Constructor Detail

Resolver

public Resolver()
Constructs a resolver.

Method Detail

createInputSource

public static InputSource createInputSource(String contentType, InputStream stream, boolean checkType, String scheme)
Returns an input source, using the MIME type information and URL scheme to statically determine the correct character encoding if possible and otherwise autodetecting it. MIME carefully specifies the character encoding defaults, and how attributes of the content type can change it. XML further specifies two mandatory encodings (UTF-8 and UTF-16), and includes an XML declaration which can be used to internally label most documents encoded using US-ASCII supersets (such as Shift_JIS, EUC-JP, ISO-2022-*, ISO-8859-*, and more).

This method can be used to access XML documents which do not have URIs (such as servlet input streams, or most JavaMail message entities) and to support access methods such as HTTP POST or PUT. (URLs normally return content using the GET method.)

The caller should set the system ID in order for relative URIs found in this document to be interpreted correctly. In some cases, a custom resolver will need to be used; for example, documents may be grouped in a single MIME "multipart/related" bundle, and relative URLs would refer to other documents in that bundle.

Parameters: contentType The MIME content type for the source for which an InputSource is desired, such as text/xml;charset=utf-8. stream The input byte stream for the input source. checkType If true, this verifies that the content type is known to support XML documents, such as application/xml. scheme Unless this is "file", unspecified MIME types default to US-ASCII. Files are always autodetected since most file systems discard character encoding information.

createInputSource

public static InputSource createInputSource(URL uri, boolean checkType)
Creates an input source from a given URI.

Parameters: uri the URI (system ID) for the entity checkType if true, the MIME content type for the entity is checked for document type and character set encoding.

createInputSource

public static InputSource createInputSource(File file)
Creates an input source from a given file, autodetecting the character encoding.

isIgnoringMIME

public boolean isIgnoringMIME()
Returns true if this resolver is ignoring MIME types in the documents it returns, to work around bugs in how servers have reported the documents' MIME types.

registerCatalogEntry

public void registerCatalogEntry(String publicId, String uri)
Registers the given public ID as corresponding to a particular URI, typically a local copy. This URI will be used in preference to ones provided as system IDs in XML entity declarations. This mechanism would most typically be used for Document Type Definitions (DTDs), where the public IDs are formally managed and versioned.

Parameters: publicId The managed public ID being mapped uri The URI of the preferred copy of that entity

registerCatalogEntry

public void registerCatalogEntry(String publicId, String resourceName, ClassLoader loader)
Registers a given public ID as corresponding to a particular Java resource in a given class loader, typically distributed with a software package. This resource will be preferred over system IDs included in XML documents. This mechanism should most typically be used for Document Type Definitions (DTDs), where the public IDs are formally managed and versioned.

If a mapping to a URI has been provided, that mapping takes precedence over this one.

Parameters: publicId The managed public ID being mapped resourceName The name of the Java resource loader The class loader holding the resource, or null if it is a system resource.

resolveEntity

public InputSource resolveEntity(String name, String uri)
SAX: Resolve the given entity into an input source. If the name can't be mapped to a preferred form of the entity, the URI is used. To resolve the entity, first a local catalog mapping names to URIs is consulted. If no mapping is found there, a catalog mapping names to java resources is consulted. Finally, if neither mapping found a copy of the entity, the specified URI is used.

When a URI is used, createInputSource is used to correctly deduce the character encoding used by this entity. No MIME type checking is done.

Parameters: name Used to find alternate copies of the entity, when this value is non-null; this is the XML "public ID". uri Used when no alternate copy of the entity is found; this is the XML "system ID", normally a URI.

setIgnoringMIME

public void setIgnoringMIME(boolean value)
Tells the resolver whether to ignore MIME types in the documents it retrieves. Many web servers incorrectly assign text documents a default character encoding, even when that is incorrect. For example, all HTTP text documents default to use ISO-8859-1 (used for Western European languages), and other MIME sources default text documents to use US-ASCII (a seven bit encoding). For XML documents which include text encoding declarations (as most should do), these server bugs can be worked around by ignoring the MIME type entirely.