Class AbstractImageSessionContext
java.lang.Object
org.apache.xmlgraphics.image.loader.impl.AbstractImageSessionContext
- All Implemented Interfaces:
ImageSessionContext
- Direct Known Subclasses:
DefaultImageSessionContext
Abstract base class for classes implementing ImageSessionContext. This class provides all the
special treatment for Source creation, i.e. it provides optimized Source objects where possible.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic interface
Implementations of this interface will be used as the mechanism for creating theSource
that wraps resources.static final class
This fallback resolver is to be used in environments where controlling file access is of critical importance.static final class
An unrestricted resolver that has various contingency mechanisms that access the file-system. -
Constructor Summary
ConstructorsConstructorDescriptionAbstractImageSessionContext
(AbstractImageSessionContext.FallbackResolver fallbackResolver) -
Method Summary
Modifier and TypeMethodDescriptionprotected static ImageInputStream
Returns a Source object for a URI.protected boolean
isReusable
(Source src) Indicates whether a Source is reusable.needSource
(String uri) Returns a Source object for a URI.Attempts to create a Source object from the given URI.protected abstract Source
resolveURI
(String uri) Attempts to resolve the given URI.void
returnSource
(String uri, Source src) Returns a Source object to a pool.static File
Convert from aURL
to aFile
.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.apache.xmlgraphics.image.loader.ImageSessionContext
getParentContext, getSourceResolution, getTargetResolution
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Constructor Details
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AbstractImageSessionContext
public AbstractImageSessionContext() -
AbstractImageSessionContext
- Parameters:
fallbackResolver
- the fallback resolution mechanism to be used when simply getting anInputStream
that backs aSource
isn't possible.
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Method Details
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resolveURI
Attempts to resolve the given URI.- Parameters:
uri
- URI to access- Returns:
- A
Source
object, or null if the URI cannot be resolved.
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newSource
Attempts to create a Source object from the given URI. If possible this method returns an ImageSource instance which provides the best possible method to access the image.- Specified by:
newSource
in interfaceImageSessionContext
- Parameters:
uri
- URI to access- Returns:
- A
Source
object, or null if the URI cannot be resolved.
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createImageInputStream
- Throws:
IOException
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toFile
Convert from aURL
to aFile
.This method will decode the URL. Syntax such as
file:///my%20docs/file.txt
will be correctly decoded to/my docs/file.txt
.Note: this method has been copied over from Apache Commons IO and enhanced to support UNC paths.
- Parameters:
url
- the file URL to convert,null
returnsnull
- Returns:
- the equivalent
File
object, ornull
if the URL's protocol is notfile
- Throws:
IllegalArgumentException
- if the file is incorrectly encoded
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getSource
Returns a Source object for a URI. This method is not guaranteed to return an instance. Implementations normally return already created Sources from a pool (normally populated through theImageSessionContext.returnSource(String, Source)
method).- Specified by:
getSource
in interfaceImageSessionContext
- Parameters:
uri
- the URI of the image- Returns:
- the Source object to load the image from, or null
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needSource
Returns a Source object for a URI. This method is guaranteed to return a Source object. If the image cannot be found, aFileNotFoundException
is thrown.- Specified by:
needSource
in interfaceImageSessionContext
- Parameters:
uri
- the URI of the image- Returns:
- the Source object to load the image from
- Throws:
FileNotFoundException
- if the image cannot be found
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returnSource
Returns a Source object to a pool. This is provided in order to reuse a Source object between the preloading and the final loading of an image. Note that not all Source objects can be reused! Non-reusable Sources are discarded.- Specified by:
returnSource
in interfaceImageSessionContext
- Parameters:
uri
- the URI of the imagesrc
- the Source object belonging to the URI
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isReusable
Indicates whether a Source is reusable. A Source object is reusable if it's anImageSource
(containing anImageInputStream
) or aDOMSource
.- Parameters:
src
- the Source object- Returns:
- true if the Source is reusable
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