Class ResourceHelper
- All Implemented Interfaces:
Resource
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Field Summary
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Constructor Summary
ConstructorsModifierConstructorDescriptionprivateResourceHelper(Resource theResource) A private for shimming the provided input. -
Method Summary
Modifier and TypeMethodDescriptionlongDetermine the content length for this resource.createRelativeResource(String relativePath) Create a resource relative to this resource.booleanexists()Return whether this resource actually exists in physical form.Return a description for this resource, to be used for error output when working with the resource.getFile()Return a File handle for this resource.Determine a filename for this resource, i.e.Return anInputStream.getURI()Return a URI handle for this resource.getURL()Return a URL handle for this resource.booleanisFile()Determine whether this resource represents a file in a file system.booleanisOpen()Return whether this resource represents a handle with an open stream.booleanReturn whether the contents of this resource can be read, e.g.longDetermine the last-modified timestamp for this resource.static Resource
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Field Details
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springResource
The cached SpringResource.
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Constructor Details
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ResourceHelper
A private for shimming the provided input.- Parameters:
theResource- the spring resource;
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Method Details
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of
@Nonnull public static Resource of(@Nonnull @ParameterName(name="springResource") Resource springResource) Return aResourcethat does all the work of the providedResource.If the input implements
Resourcethen it is cast to the output, other a shim class is generated.- Parameters:
springResource- the input- Returns:
- a
Resourcewhich reflects what the Spring one does
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getInputStream
Return anInputStream.It is expected that each call creates a fresh stream.
This requirement is particularly important when you consider an API such as JavaMail, which needs to be able to read the stream multiple times when creating mail attachments. For such a use case, it is required that each
getInputStream()call returns a fresh stream.- Specified by:
getInputStreamin interfaceResource- Returns:
- the input stream for the underlying resource (must not be
null) - Throws:
IOException- if the stream could not be opened
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exists
public boolean exists()Return whether this resource actually exists in physical form.This method performs a definitive existence check, whereas the existence of a
Resourcehandle only guarantees a valid descriptor handle. -
isFile
public boolean isFile()Determine whether this resource represents a file in a file system.A value of
truestrongly suggests (but does not guarantee) that aResource.getFile()call will succeed.This is conservatively
falseby default. -
isReadable
public boolean isReadable()Return whether the contents of this resource can be read, e.g. viaResource.getInputStream()orResource.getFile().Will be
truefor typical resource descriptors; note that actual content reading may still fail when attempted. However, a value offalseis a definitive indication that the resource content cannot be read.- Specified by:
isReadablein interfaceResource- Returns:
- whether the contents of this resource can be read.
- See Also:
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isOpen
public boolean isOpen()Return whether this resource represents a handle with an open stream. If true, the InputStream cannot be read multiple times, and must be read and closed to avoid resource leaks.Will be
falsefor typical resource descriptors. -
getURL
Return a URL handle for this resource.- Specified by:
getURLin interfaceResource- Returns:
- a URL handle for this resource.
- Throws:
IOException- if the resource cannot be resolved as URL, i.e. if the resource is not available as descriptor
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getURI
Return a URI handle for this resource.- Specified by:
getURIin interfaceResource- Returns:
- a URI handle for this resource.
- Throws:
IOException- if the resource cannot be resolved as URI, i.e. if the resource is not available as descriptor
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getFile
Return a File handle for this resource.- Specified by:
getFilein interfaceResource- Returns:
- a File handle for this resource.
- Throws:
IOException- if the resource cannot be resolved as absolute file path, i.e. if the resource is not available in a file system
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contentLength
Determine the content length for this resource.- Specified by:
contentLengthin interfaceResource- Returns:
- the content length for this resource.
- Throws:
IOException- if the resource cannot be resolved (in the file system or as some other known physical resource type)
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lastModified
Determine the last-modified timestamp for this resource.- Specified by:
lastModifiedin interfaceResource- Returns:
- the last-modified timestamp for this resource.
- Throws:
IOException- if the resource cannot be resolved (in the file system or as some other known physical resource type)
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createRelativeResource
Create a resource relative to this resource.- Specified by:
createRelativeResourcein interfaceResource- Parameters:
relativePath- the relative path (relative to this resource)- Returns:
- the resource handle for the relative resource
- Throws:
IOException- if the relative resource cannot be determined
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getFilename
Determine a filename for this resource, i.e. typically the last part of the path: for example, "myfile.txt".- Specified by:
getFilenamein interfaceResource- Returns:
nullif this type of resource does not have a filename, otherwise the file name.
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getDescription
Return a description for this resource, to be used for error output when working with the resource.Implementations are also encouraged to return this value from their
toStringmethod.- Specified by:
getDescriptionin interfaceResource- Returns:
- a description for this resource.
- See Also:
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