| java.lang.Object
 com.sun.xml.dtdparser.Resolver
| Resolver | | public class Resolver implements EntityResolver(Code) | | 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:
- Static factory methods are provided for constructing SAX InputSource
objects from Files, URLs, or MIME objects. This eliminates a class of
error-prone coding in applications.
- Character encodings for XML documents are correctly supported:
- The encodings defined in the RFCs for MIME content types
(2046 for general MIME, and 2376 for XML in particular), are
supported, handling charset=... attributes and accepting
content types which are known to be safe for use with XML;
- The character encoding autodetection algorithm identified
in the XML specification is used, and leverages all of
the JDK 1.1 (and later) character encoding support.
- The use of MIME typing may optionally be disabled, forcing the
use of autodetection, to support web servers which don't correctly
report MIME types for XML. For example, they may report text that
is encoded in EUC-JP as being US-ASCII text, leading to fatal
errors during parsing.
- The InputSource objects returned by this class always
have a
java.io.Reader available as the "character
stream" property.
- Catalog entries can map public identifiers to Java resources or
to local URLs. These are used to reduce network dependencies and loads,
and will often be used for external DTD components. For example, packages
shipping DTD files as resources in JAR files can eliminate network traffic
when accessing them, and sites may provide local caches of common DTDs.
Note that no particular catalog syntax is supported by this class, only
the notion of a set of entries.
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).
author:
David Brownell
author:
Janet Koenig
version:
1.3 00/02/24 |
| Constructor Summary | |
| public | Resolver()
Constructs a resolver. |
| Method Summary | |
| 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. | | public static InputSource | createInputSource(URL uri, boolean checkType)
Creates an input source from a given URI. | | public static InputSource | createInputSource(File file)
Creates an input source from a given file, autodetecting
the character encoding. | | 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. | | public void | registerCatalogEntry(String publicId, String uri)
Registers the given public ID as corresponding to a particular
URI, typically a local copy. | | 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. | | public InputSource | resolveEntity(String name, String uri)
SAX:
Resolve the given entity into an input source. | | public void | setIgnoringMIME(boolean value)
Tells the resolver whether to ignore MIME types in the documents it
retrieves. |
| Resolver | | public Resolver()(Code) | | Constructs a resolver.
|
| createInputSource | | public static InputSource createInputSource(String contentType, InputStream stream, boolean checkType, String scheme) throws IOException(Code) | | 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 whichan InputSource is desired, such as text/xml;charset=utf-8.
Parameters:
stream - The input byte stream for the input source.
Parameters:
checkType - If true, this verifies that the content type is knownto support XML documents, such as application/xml.
Parameters:
scheme - Unless this is "file", unspecified MIME typesdefault to US-ASCII. Files are always autodetected since mostfile systems discard character encoding information. |
| createInputSource | | public static InputSource createInputSource(URL uri, boolean checkType) throws IOException(Code) | | Creates an input source from a given URI.
Parameters:
uri - the URI (system ID) for the entity
Parameters:
checkType - if true, the MIME content type for the entityis checked for document type and character set encoding. |
| createInputSource | | public static InputSource createInputSource(File file) throws IOException(Code) | | Creates an input source from a given file, autodetecting
the character encoding.
|
| isIgnoringMIME | | public boolean isIgnoringMIME()(Code) | | 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)(Code) | | 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
Parameters:
uri - The URI of the preferred copy of that entity |
| registerCatalogEntry | | public void registerCatalogEntry(String publicId, String resourceName, ClassLoader loader)(Code) | | 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
Parameters:
resourceName - The name of the Java resource
Parameters:
loader - The class loader holding the resource, or null ifit is a system resource. |
| resolveEntity | | public InputSource resolveEntity(String name, String uri) throws IOException(Code) | | 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, whenthis value is non-null; this is the XML "public ID".
Parameters:
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)(Code) | | 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.
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