liquibase.resource

Interface ResourceAccessor

All Known Implementing Classes:

AbstractResourceAccessor, AntResourceAccessor, ClassLoaderResourceAccessor, CommandLineResourceAccessor, CompositeResourceAccessor, FileSystemResourceAccessor, MavenResourceAccessor, MockResourceAccessor, OSGiResourceAccessor, SearchPathResourceAccessor, SpringResourceAccessor

public interface ResourceAccessor

ResourceAccessors abstract file access so they can be read in a variety of environments. Implementations may look for local files in known locations, read from the network, or do whatever else they need to find files. Think of ResourceAccessors as a ClassLoader but for finding and reading files, not finding and loading classes.

Method Summary

Modifier and Type	Method and Description
SortedSet<String>	describeLocations() Returns a description of the places this classloader will look for paths.
SortedSet<String>	list(String relativeTo, String path, boolean recursive, boolean includeFiles, boolean includeDirectories) Returns the path to all resources contained in the given path.
InputStream	openStream(String relativeTo, String streamPath) Returns a single stream matching the given path.
InputStreamList	openStreams(String relativeTo, String streamPath) Return the streams for each resource mapped by the given path.

Method Detail

openStreams

InputStreamList openStreams(String relativeTo,
                            String streamPath)
                     throws IOException

Return the streams for each resource mapped by the given path. The path is often a URL but does not have to be. Should accept both / and \ chars for file paths to be platform-independent. If path points to a compressed resource, return a stream of the uncompressed contents of the file. Returns InputStreamList since multiple resources can map to the same path, such as "META-INF/MAINFEST.MF". Remember to close streams when finished with them.

Parameters:

relativeTo - Location that streamPath should be found relative to. If null, streamPath is an absolute path

Returns:

Empty list if the resource does not exist.

Throws:

IOException - if there is an error reading an existing path.

openStream

InputStream openStream(String relativeTo,
                       String streamPath)
                throws IOException

Returns a single stream matching the given path. See openStreams(String, String) for details about path options. Implementations should respect GlobalConfiguration.DUPLICATE_FILE_MODE

Parameters:

relativeTo - Location that streamPath should be found relative to. If null, streamPath is an absolute path

Returns:

null if the resource does not exist

Throws:

IOException - if multiple paths matched the stream

IOException - if there is an error reading an existing path

list

SortedSet<String> list(String relativeTo,
                       String path,
                       boolean recursive,
                       boolean includeFiles,
                       boolean includeDirectories)
                throws IOException

Returns the path to all resources contained in the given path. The passed path is not included in the returned set. Returned strings should use "/" for file path separators, regardless of the OS and should accept both / and \ chars for file paths to be platform-independent. Returned set is sorted, normally alphabetically but subclasses can use different comparators. The values returned should be able to be passed into openStreams(String, String) and return the contents. Returned paths should normally be root-relative and therefore not be an absolute path, unless there is a good reason to be absolute.

Parameters:

relativeTo - Location that streamPath should be found relative to. If null, path is an absolute path

path - The path to lookup resources in.

recursive - Set to true and will return paths to contents in sub directories as well.

includeFiles - Set to true and will return paths to files.

includeDirectories - Set to true and will return paths to directories.

Returns:

empty set if nothing was found

Throws:

IOException - if there is an error reading an existing root.

describeLocations

SortedSet<String> describeLocations()

Returns a description of the places this classloader will look for paths. Used in error messages and other troubleshooting cases.