org.apache.tools.ant.types

Class XMLCatalog

Implemented Interfaces:
Cloneable, EntityResolver, URIResolver

public class XMLCatalog
extends DataType
implements Cloneable, EntityResolver, URIResolver

This data type provides a catalog of resource locations (such as DTDs and XML entities), based on the OASIS "Open Catalog" standard. The catalog entries are used both for Entity resolution and URI resolution, in accordance with the EntityResolver and URIResolver interfaces as defined in the Java API for XML Processing Specification.

Resource locations can be specified either in-line or in external catalog file(s), or both. In order to use an external catalog file, the xml-commons resolver library ("resolver.jar") must be in your classpath. External catalog files may be either plain text format or XML format. If the xml-commons resolver library is not found in the classpath, external catalog files, specified in <catalogpath> paths, will be ignored and a warning will be logged. In this case, however, processing of inline entries will proceed normally.

Currently, only <dtd> and <entity> elements may be specified inline; these correspond to OASIS catalog entry types PUBLIC and URI respectively.

The following is a usage example: <xmlcatalog>
  <dtd publicId="" location="/path/to/file.jar" />
  <dtd publicId="" location="/path/to/file2.jar" />
  <entity publicId="" location="/path/to/file3.jar" />
  <entity publicId="" location="/path/to/file4.jar" />
  <catalogpath>
    <pathelement location="/etc/sgml/catalog"/>
  </catalogpath>
  <catalogfiles dir="/opt/catalogs/" includes="**\catalog.xml" />
</xmlcatalog>

Tasks wishing to use <xmlcatalog> must provide a method called createXMLCatalog which returns an instance of XMLCatalog. Nested DTD and entity definitions are handled by the XMLCatalog object and must be labeled dtd and entity respectively.

The following is a description of the resolution algorithm: entities/URIs/dtds are looked up in each of the following contexts, stopping when a valid and readable resource is found:

  1. In the local filesystem
  2. In the classpath
  3. Using the Apache xml-commons resolver (if it is available)
  4. In URL-space

See XMLValidateTask for an example of a task that has integrated support for XMLCatalogs.

Possible future extension could provide for additional OASIS entry types to be specified inline.

Field Summary

static String
APACHE_RESOLVER
The name of the bridge to the Apache xml-commons resolver class, used to determine whether resolver.jar is present in the classpath.
static String
CATALOG_RESOLVER
Resolver base class

Fields inherited from class org.apache.tools.ant.types.DataType

checked, description, ref

Fields inherited from class org.apache.tools.ant.ProjectComponent

project

Constructor Summary

XMLCatalog()
Default constructor

Method Summary

void
addConfiguredXMLCatalog(XMLCatalog catalog)
Loads a nested <xmlcatalog> into our definition.
void
addDTD(ResourceLocation dtd)
Creates the nested <dtd> element.
void
addEntity(ResourceLocation entity)
Creates the nested <entity> element.
Path
createCatalogPath()
Creates a nested <catalogpath> element.
Path
createClasspath()
Allows nested classpath elements.
Path
getCatalogPath()
Returns the catalog path in which to attempt to resolve DTDs.
Source
resolve(String href, String base)
Implements the URIResolver.resolve() interface method.
InputSource
resolveEntity(String publicId, String systemId)
Implements the EntityResolver.resolveEntity() interface method.
void
setCatalogPathRef(Reference r)
Allows catalogpath reference.
void
setClasspath(Path classpath)
Allows simple classpath string.
void
setClasspathRef(Reference r)
Allows classpath reference.
void
setRefid(Reference r)
Makes this instance in effect a reference to another XMLCatalog instance.

Methods inherited from class org.apache.tools.ant.types.DataType

checkAttributesAllowed, checkChildrenAllowed, circularReference, dieOnCircularReference, getCheckedRef, getDescription, getRefid, isChecked, isReference, noChildrenAllowed, setChecked, setDescription, setRefid, tooManyAttributes

Methods inherited from class org.apache.tools.ant.ProjectComponent

getProject, log, log, setProject

Field Details

APACHE_RESOLVER

public static final String APACHE_RESOLVER
The name of the bridge to the Apache xml-commons resolver class, used to determine whether resolver.jar is present in the classpath.

CATALOG_RESOLVER

public static final String CATALOG_RESOLVER
Resolver base class

Constructor Details

XMLCatalog

public XMLCatalog()
Default constructor

Method Details

addConfiguredXMLCatalog

public void addConfiguredXMLCatalog(XMLCatalog catalog)
Loads a nested <xmlcatalog> into our definition. Not allowed if this catalog is itself a reference to another catalog -- that is, a catalog cannot both refer to another and contain elements or other attributes.
Parameters:
catalog - Nested XMLCatalog

addDTD

public void addDTD(ResourceLocation dtd)
            throws BuildException
Creates the nested <dtd> element. Not allowed if this catalog is itself a reference to another catalog -- that is, a catalog cannot both refer to another and contain elements or other attributes.
Parameters:
dtd - the information about the PUBLIC resource mapping to be added to the catalog
Throws:
BuildException - if this is a reference and no nested elements are allowed.

addEntity

public void addEntity(ResourceLocation entity)
            throws BuildException
Creates the nested <entity> element. Not allowed if this catalog is itself a reference to another catalog -- that is, a catalog cannot both refer to another and contain elements or other attributes.
Parameters:
entity - the information about the URI resource mapping to be added to the catalog.
Throws:
BuildException - if this is a reference and no nested elements are allowed.

createCatalogPath

public Path createCatalogPath()
Creates a nested <catalogpath> element. Not allowed if this catalog is itself a reference to another catalog -- that is, a catalog cannot both refer to another and contain elements or other attributes.
Returns:
a path to be configured as the catalog path.

createClasspath

public Path createClasspath()
Allows nested classpath elements. Not allowed if this catalog is itself a reference to another catalog -- that is, a catalog cannot both refer to another and contain elements or other attributes.
Returns:
a Path instance to be configured.

getCatalogPath

public Path getCatalogPath()
Returns the catalog path in which to attempt to resolve DTDs.
Returns:
the catalog path

resolve

public Source resolve(String href,
                      String base)
            throws TransformerException
Implements the URIResolver.resolve() interface method.
See Also:
javax.xml.transform.URIResolver.resolve

resolveEntity

public InputSource resolveEntity(String publicId,
                                 String systemId)
            throws SAXException,
                   IOException
Implements the EntityResolver.resolveEntity() interface method.
See Also:
org.xml.sax.EntityResolver.resolveEntity

setCatalogPathRef

public void setCatalogPathRef(Reference r)
Allows catalogpath reference. Not allowed if this catalog is itself a reference to another catalog -- that is, a catalog cannot both refer to another and contain elements or other attributes.
Parameters:
r - an Ant reference containing a classpath to be used as the catalog path.

setClasspath

public void setClasspath(Path classpath)
Allows simple classpath string. Not allowed if this catalog is itself a reference to another catalog -- that is, a catalog cannot both refer to another and contain elements or other attributes.
Parameters:
classpath - the classpath to use to look up entities.

setClasspathRef

public void setClasspathRef(Reference r)
Allows classpath reference. Not allowed if this catalog is itself a reference to another catalog -- that is, a catalog cannot both refer to another and contain elements or other attributes.
Parameters:
r - an Ant reference containing a classpath.

setRefid

public void setRefid(Reference r)
            throws BuildException
Makes this instance in effect a reference to another XMLCatalog instance.

You must not set another attribute or nest elements inside this element if you make it a reference. That is, a catalog cannot both refer to another and contain elements or attributes.

Overrides:
setRefid in interface DataType
Parameters:
r - the reference to which this catalog instance is associated
Throws:
BuildException - if this instance already has been configured.

Copyright B) 2000-2007 Apache Software Foundation. All Rights Reserved.