FileStore (Java Platform SE 8 ) (original) (raw)
- java.nio.file.FileStore
public abstract class FileStore
extends Object
Storage for files. A FileStore represents a storage pool, device, partition, volume, concrete file system or other implementation specific means of file storage. The FileStore for where a file is stored is obtained by invoking the getFileStore method, or all file stores can be enumerated by invoking the getFileStores method.
In addition to the methods defined by this class, a file store may support one or more FileStoreAttributeView classes that provide a read-only or updatable view of a set of file store attributes.
Since:
1.7
Constructor Summary
Constructors
Modifier Constructor Description protected FileStore() Initializes a new instance of this class. Method Summary
All Methods Instance Methods Abstract Methods
Modifier and Type Method Description abstract Object getAttribute(String attribute) Reads the value of a file store attribute. abstract <V extends FileStoreAttributeView>V getFileStoreAttributeView(Class type) Returns a FileStoreAttributeView of the given type. abstract long getTotalSpace() Returns the size, in bytes, of the file store. abstract long getUnallocatedSpace() Returns the number of unallocated bytes in the file store. abstract long getUsableSpace() Returns the number of bytes available to this Java virtual machine on the file store. abstract boolean isReadOnly() Tells whether this file store is read-only. abstract String name() Returns the name of this file store. abstract boolean supportsFileAttributeView(Class<? extends FileAttributeView> type) Tells whether or not this file store supports the file attributes identified by the given file attribute view. abstract boolean supportsFileAttributeView(String name) Tells whether or not this file store supports the file attributes identified by the given file attribute view. abstract String type() Returns the type of this file store. * ### Methods inherited from class java.lang.[Object](../../../java/lang/Object.html "class in java.lang") `[clone](../../../java/lang/Object.html#clone--), [equals](../../../java/lang/Object.html#equals-java.lang.Object-), [finalize](../../../java/lang/Object.html#finalize--), [getClass](../../../java/lang/Object.html#getClass--), [hashCode](../../../java/lang/Object.html#hashCode--), [notify](../../../java/lang/Object.html#notify--), [notifyAll](../../../java/lang/Object.html#notifyAll--), [toString](../../../java/lang/Object.html#toString--), [wait](../../../java/lang/Object.html#wait--), [wait](../../../java/lang/Object.html#wait-long-), [wait](../../../java/lang/Object.html#wait-long-int-)`Constructor Detail
* #### FileStore protected FileStore() Initializes a new instance of this class.Method Detail
* #### name public abstract [String](../../../java/lang/String.html "class in java.lang") name() Returns the name of this file store. The format of the name is highly implementation specific. It will typically be the name of the storage pool or volume. The string returned by this method may differ from the string returned by the [toString](../../../java/lang/Object.html#toString--) method. Returns: the name of this file store * #### type public abstract [String](../../../java/lang/String.html "class in java.lang") type() Returns the _type_ of this file store. The format of the string returned by this method is highly implementation specific. It may indicate, for example, the format used or if the file store is local or remote. Returns: a string representing the type of this file store * #### isReadOnly public abstract boolean isReadOnly() Tells whether this file store is read-only. A file store is read-only if it does not support write operations or other changes to files. Any attempt to create a file, open an existing file for writing etc. causes an `IOException` to be thrown. Returns: `true` if, and only if, this file store is read-only * #### getTotalSpace public abstract long getTotalSpace() throws [IOException](../../../java/io/IOException.html "class in java.io") Returns the size, in bytes, of the file store. Returns: the size of the file store, in bytes Throws: `[IOException](../../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs * #### getUsableSpace public abstract long getUsableSpace() throws [IOException](../../../java/io/IOException.html "class in java.io") Returns the number of bytes available to this Java virtual machine on the file store. The returned number of available bytes is a hint, but not a guarantee, that it is possible to use most or any of these bytes. The number of usable bytes is most likely to be accurate immediately after the space attributes are obtained. It is likely to be made inaccurate by any external I/O operations including those made on the system outside of this Java virtual machine. Returns: the number of bytes available Throws: `[IOException](../../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs * #### getUnallocatedSpace public abstract long getUnallocatedSpace() throws [IOException](../../../java/io/IOException.html "class in java.io") Returns the number of unallocated bytes in the file store. The returned number of unallocated bytes is a hint, but not a guarantee, that it is possible to use most or any of these bytes. The number of unallocated bytes is most likely to be accurate immediately after the space attributes are obtained. It is likely to be made inaccurate by any external I/O operations including those made on the system outside of this virtual machine. Returns: the number of unallocated bytes Throws: `[IOException](../../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs * #### supportsFileAttributeView public abstract boolean supportsFileAttributeView([Class](../../../java/lang/Class.html "class in java.lang")<? extends [FileAttributeView](../../../java/nio/file/attribute/FileAttributeView.html "interface in java.nio.file.attribute")> type) Tells whether or not this file store supports the file attributes identified by the given file attribute view. Invoking this method to test if the file store supports [BasicFileAttributeView](../../../java/nio/file/attribute/BasicFileAttributeView.html "interface in java.nio.file.attribute") will always return `true`. In the case of the default provider, this method cannot guarantee to give the correct result when the file store is not a local storage device. The reasons for this are implementation specific and therefore unspecified. Parameters: `type` \- the file attribute view type Returns: `true` if, and only if, the file attribute view is supported * #### supportsFileAttributeView public abstract boolean supportsFileAttributeView([String](../../../java/lang/String.html "class in java.lang") name) Tells whether or not this file store supports the file attributes identified by the given file attribute view. Invoking this method to test if the file store supports [BasicFileAttributeView](../../../java/nio/file/attribute/BasicFileAttributeView.html "interface in java.nio.file.attribute"), identified by the name "`basic`" will always return `true`. In the case of the default provider, this method cannot guarantee to give the correct result when the file store is not a local storage device. The reasons for this are implementation specific and therefore unspecified. Parameters: `name` \- the [name](../../../java/nio/file/attribute/AttributeView.html#name--) of file attribute view Returns: `true` if, and only if, the file attribute view is supported * #### getFileStoreAttributeView public abstract <V extends [FileStoreAttributeView](../../../java/nio/file/attribute/FileStoreAttributeView.html "interface in java.nio.file.attribute")> V getFileStoreAttributeView([Class](../../../java/lang/Class.html "class in java.lang")<V> type) Returns a `FileStoreAttributeView` of the given type. This method is intended to be used where the file store attribute view defines type-safe methods to read or update the file store attributes. The `type` parameter is the type of the attribute view required and the method returns an instance of that type if supported. Type Parameters: `V` \- The `FileStoreAttributeView` type Parameters: `type` \- the `Class` object corresponding to the attribute view Returns: a file store attribute view of the specified type or`null` if the attribute view is not available * #### getAttribute public abstract [Object](../../../java/lang/Object.html "class in java.lang") getAttribute([String](../../../java/lang/String.html "class in java.lang") attribute) throws [IOException](../../../java/io/IOException.html "class in java.io") Reads the value of a file store attribute. The `attribute` parameter identifies the attribute to be read and takes the form: > _view-name_**:**_attribute-name_ where the character `':'` stands for itself. _view-name_ is the [name](../../../java/nio/file/attribute/AttributeView.html#name--) of a [AttributeView](../../../java/nio/file/FileStore.html "class in java.nio.file") that identifies a set of file attributes._attribute-name_ is the name of the attribute. **Usage Example:** Suppose we want to know if ZFS compression is enabled (assuming the "zfs" view is supported): boolean compression = (Boolean)fs.getAttribute("zfs:compression"); Parameters: `attribute` \- the attribute to read Returns: the attribute value; `null` may be a valid valid for some attributes Throws: `[UnsupportedOperationException](../../../java/lang/UnsupportedOperationException.html "class in java.lang")` \- if the attribute view is not available or it does not support reading the attribute `[IOException](../../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs
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