src/main/java/com/google/jimfs/internal/JimfsFileStore.java - platform/external/jimfs - Git at Google

 /*
  * Copyright 2013 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package com.google.jimfs.internal;

 import static com.google.common.base.Preconditions.checkNotNull;

 import com.google.common.base.Splitter;
 import com.google.common.base.Supplier;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.jimfs.internal.attribute.AttributeProvider;
 import com.google.jimfs.internal.attribute.AttributeProviderRegistry;
 import com.google.jimfs.internal.file.ArrayByteStore;
 import com.google.jimfs.internal.file.DirectoryTable;
 import com.google.jimfs.internal.file.File;
 import com.google.jimfs.internal.file.FileContent;
 import com.google.jimfs.internal.path.JimfsPath;

 import java.io.IOException;
 import java.nio.file.FileStore;
 import java.nio.file.FileSystem;
 import java.nio.file.Files;
 import java.nio.file.LinkOption;
 import java.nio.file.Path;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.nio.file.attribute.FileAttribute;
 import java.nio.file.attribute.FileAttributeView;
 import java.nio.file.attribute.FileStoreAttributeView;
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicLong;

 import javax.annotation.Nullable;

 /**
  * Service for creating and copying files as well as reading and setting attributes on them.
  *
  * @author Colin Decker
  */
 public final class JimfsFileStore extends FileStore {

   private static final String ALL_ATTRIBUTES = "*";

   private final AtomicLong idGenerator = new AtomicLong();

   private final String name;
   private final AttributeProviderRegistry attributeProviders;

   /** Directory supplier with no extra file attributes. */
   private final Supplier<File> defaultDirectorySupplier = new DirectorySupplier();
   /** Regular file supplier with no extra file attributes. */
   private final Supplier<File> defaultRegularFileSupplier = new RegularFileSupplier();

   /**
    * Creates a new file service using the given providers to handle file attributes.
    */
   public JimfsFileStore(String name, AttributeProvider... providers) {
     this(name, Arrays.asList(providers));
   }

   /**
    * Creates a new file service using the given providers to handle file attributes.
    */
   public JimfsFileStore(String name, Iterable<? extends AttributeProvider> providers) {
     this.name = checkNotNull(name);
     this.attributeProviders = new AttributeProviderRegistry(providers);
   }

   @Override
   public String name() {
     return name;
   }

   @Override
   public String type() {
     return "jimfs";
   }

   @Override
   public boolean isReadOnly() {
     return false;
   }

   @Override
   public long getTotalSpace() throws IOException {
     return Integer.MAX_VALUE;
   }

   @Override
   public long getUsableSpace() throws IOException {
     return Integer.MAX_VALUE;
   }

   @Override
   public long getUnallocatedSpace() throws IOException {
     return Integer.MAX_VALUE;
   }

   private long nextFileId() {
     return idGenerator.getAndIncrement();
   }

   private File createFile(long id, FileContent content, FileAttribute<?>... attrs) {
     File file = new File(id, content);
     setInitialAttributes(file);
     for (FileAttribute<?> attr : attrs) {
       setAttributeInternal(file, attr.name(), attr.value(), true);
     }
     return file;
   }

   /**
    * Creates a new directory and stores it. Returns the key of the new file.
    */
   public File createDirectory(FileAttribute<?>... attrs) {
     return createFile(nextFileId(), new DirectoryTable(), attrs);
   }

   /**
    * Creates a new regular file and stores it. Returns the key of the new file.
    */
   public File createRegularFile(FileAttribute<?>... attrs) {
     return createFile(nextFileId(), new ArrayByteStore(), attrs);
   }

   /**
    * Creates a new symbolic link referencing the given target path and stores it. Returns the key of
    * the new file.
    */
   public File createSymbolicLink(JimfsPath target, FileAttribute<?>... attrs) {
     return createFile(nextFileId(), target, attrs);
   }

   /**
    * Creates copies of the given file metadata and content and stores them. Returns the key of the
    * new file.
    */
   public File copy(File file) {
     return createFile(nextFileId(), file.content().copy());
   }

   /**
    * Returns a supplier that creates directories and sets the given attributes.
    */
   public Supplier<File> directorySupplier(FileAttribute<?>... attrs) {
     return attrs.length == 0 ? defaultDirectorySupplier : new DirectorySupplier(attrs);
   }

   /**
    * Returns a supplier that creates a regular files and sets the given attributes.
    */
   public Supplier<File> regularFileSupplier(FileAttribute<?>... attrs) {
     return attrs.length == 0 ? defaultRegularFileSupplier : new RegularFileSupplier(attrs);
   }

   /**
    * Returns a supplier that creates a symbolic links to the given path and sets the given
    * attributes.
    */
   public Supplier<File> symbolicLinkSupplier(JimfsPath target, FileAttribute<?>... attrs) {
     return new SymbolicLinkSupplier(target, attrs);
   }

   /**
    * Implements {@link FileSystem#supportedFileAttributeViews()}.
    */
   public ImmutableSet<String> supportedFileAttributeViews() {
     return attributeProviders.getSupportedViews();
   }

   /**
    * Implements {@link FileStore#supportsFileAttributeView(Class)}.
    */
   public boolean supportsFileAttributeView(Class<? extends FileAttributeView> type) {
     return attributeProviders.getSupportedViewTypes().contains(type);
   }

   @Override
   public boolean supportsFileAttributeView(String name) {
     return supportedFileAttributeViews().contains(name);
   }

   /**
    * Sets all initial attributes for the given file.
    */
   private void setInitialAttributes(File file) {
     for (AttributeProvider provider : attributeProviders.getProviders()) {
       provider.setInitial(file);
     }
   }

   /**
    * Gets the value of the given attribute for the given file. {@code attribute} must be of the form
    * "view:attribute" or "attribute".
    */
   public <V> V getAttribute(File file, String attribute) {
     String view = getViewName(attribute);
     String attr = getSingleAttribute(attribute);
     return getAttribute(file, view, attr);
   }

   /**
    * Gets the value of the given attribute for the given view and file. Neither view nor file may
    * have a ':' character.
    */
   @SuppressWarnings("unchecked")
   public <V> V getAttribute(File file, String view, String attribute) {
     for (AttributeProvider provider : attributeProviders.getProviders(view)) {
       if (provider.isGettable(file, attribute)) {
         return (V) provider.get(file, attribute);
       }
     }

     throw new IllegalArgumentException("attribute not found: " + attribute);
   }

   /**
    * Sets the value of the given attribute to the given value for the given file.
    */
   public void setAttribute(File file, String attribute, Object value) {
     setAttributeInternal(file, attribute, value, false);
   }

   /**
    * Sets the value of the given attribute to the given value for the given view and file.
    */
   public void setAttribute(File file, String view, String attribute, Object value) {
     setAttributeInternal(file, view, attribute, value, false);
   }

   private void setAttributeInternal(File file, String attribute, Object value, boolean create) {
     String view = getViewName(attribute);
     String attr = getSingleAttribute(attribute);
     setAttributeInternal(file, view, attr, value, create);
   }

   private void setAttributeInternal(
       File file, String view, String attribute, Object value, boolean create) {
     for (AttributeProvider provider : attributeProviders.getProviders(view)) {
       if (provider.isSettable(file, attribute)) {
         if (create && !provider.isSettableOnCreate(attribute)) {
           throw new UnsupportedOperationException(
               "cannot set attribute '" + view + ":" + attribute + "' during file creation");
         }

         ImmutableSet<Class<?>> acceptedTypes = provider.acceptedTypes(attribute);
         boolean validType = false;
         for (Class<?> type : acceptedTypes) {
           if (type.isInstance(value)) {
             validType = true;
             break;
           }
         }

         if (validType) {
           provider.set(file, attribute, value);
           return;
         } else {
           Object acceptedTypeMessage = acceptedTypes.size() == 1
               ? acceptedTypes.iterator().next()
               : "one of " + acceptedTypes;
           throw new IllegalArgumentException("invalid type " + value.getClass()
               + " for attribute '" + view + ":" + attribute + "': should be "
               + acceptedTypeMessage);
         }
       }
     }

     throw new IllegalArgumentException("cannot set attribute '" + view + ":" + attribute + "'");
   }

   /**
    * Returns an attribute view of the given type for the given file provider, or {@code null} if the
    * view type is not supported.
    */
   @Nullable
   public <V extends FileAttributeView> V getFileAttributeView(
       FileProvider fileProvider, Class<V> type) {
     if (supportsFileAttributeView(type)) {
       return attributeProviders.getViewProvider(type).getView(fileProvider);
     }

     return null;
   }

   /**
    * Implements {@link Files#readAttributes(Path, String, LinkOption...)}.
    */
   public ImmutableMap<String, Object> readAttributes(File file, String attributes) {
     String view = getViewName(attributes);
     List<String> attrs = getAttributeNames(attributes);

     if (attrs.size() > 1 && attrs.contains(ALL_ATTRIBUTES)) {
       // attrs contains * and other attributes
       throw new IllegalArgumentException("invalid attributes: " + attributes);
     }

     ImmutableMap.Builder<String, Object> result = ImmutableMap.builder();
     if (attrs.size() == 1 && attrs.contains(ALL_ATTRIBUTES)) {
       // for 'view:*' format, get all keys for all providers for the view
       for (AttributeProvider provider : attributeProviders.getProviders(view)) {
         provider.readAll(file, result);
       }
     } else {
       // for 'view:attr1,attr2,etc'
       for (String attr : attrs) {
         boolean found = false;
         for (AttributeProvider provider : attributeProviders.getProviders(view)) {
           if (provider.isGettable(file, attr)) {
             result.put(attr, provider.get(file, attr));
             found = true;
             break;
           }
         }

         if (!found) {
           throw new IllegalArgumentException("invalid attribute for view '" + view + "': " + attr);
         }
       }
     }

     return result.build();
   }

   /**
    * Returns attributes of the given file as an object of the given type.
    *
    * @throws UnsupportedOperationException if the given attributes type is not supported
    */
   public <A extends BasicFileAttributes> A readAttributes(File file, Class<A> type) {
     if (attributeProviders.getSupportedAttributesTypes().contains(type)) {
       return attributeProviders.getReader(type).read(file);
     }

     throw new UnsupportedOperationException("unsupported attributes type: " + type);
   }

   private static String getViewName(String attribute) {
     int separatorIndex = attribute.indexOf(':');

     if (separatorIndex == -1) {
       return "basic";
     }

     // separator must not be at the start or end of the string or appear more than once
     if (separatorIndex == 0
         || separatorIndex == attribute.length() - 1
         || attribute.indexOf(':', separatorIndex + 1) != -1) {
       throw new IllegalArgumentException("illegal attribute format: " + attribute);
     }

     return attribute.substring(0, separatorIndex);
   }

   private static final Splitter ATTRIBUTE_SPLITTER = Splitter.on(',');

   private static ImmutableList<String> getAttributeNames(String attributes) {
     int separatorIndex = attributes.indexOf(':');
     String attributesPart = attributes.substring(separatorIndex + 1);

     return ImmutableList.copyOf(ATTRIBUTE_SPLITTER.split(attributesPart));
   }

   private static String getSingleAttribute(String attribute) {
     ImmutableList<String> attributeNames = getAttributeNames(attribute);

     if (attributeNames.size() != 1 || ALL_ATTRIBUTES.equals(attributeNames.get(0))) {
       throw new IllegalArgumentException("must specify a single attribute: " + attribute);
     }

     return attributeNames.get(0);
   }

   /**
    * Returns {@code null}. This file store does not support any file store attribute views.
    */
   @Override
   public <V extends FileStoreAttributeView> V getFileStoreAttributeView(Class<V> type) {
     return null;
   }

   /**
    * Throws {@link UnsupportedOperationException}. This file store does not support any file store
    * attributes.
    */
   @Override
   public Object getAttribute(String attribute) throws IOException {
     throw new UnsupportedOperationException();
   }

   private abstract class FileSupplier implements Supplier<File> {

     protected final FileAttribute<?>[] attrs;

     protected FileSupplier(FileAttribute<?>[] attrs) {
       this.attrs = checkNotNull(attrs);
     }
   }

   private final class DirectorySupplier extends FileSupplier {

     private DirectorySupplier(FileAttribute<?>... attrs) {
       super(attrs);
     }

     @Override
     public File get() {
       return createDirectory(attrs);
     }
   }

   private final class RegularFileSupplier extends FileSupplier {

     private RegularFileSupplier(FileAttribute<?>... attrs) {
       super(attrs);
     }

     @Override
     public File get() {
       return createRegularFile(attrs);
     }
   }

   private final class SymbolicLinkSupplier extends FileSupplier {

     private final JimfsPath target;

     protected SymbolicLinkSupplier(JimfsPath target, FileAttribute<?>... attrs) {
       super(attrs);
       this.target = checkNotNull(target);
     }

     @Override
     public File get() {
       return createSymbolicLink(target, attrs);
     }
   }
 }
	/*
	* Copyright 2013 Google Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.google.jimfs.internal;

	import static com.google.common.base.Preconditions.checkNotNull;

	import com.google.common.base.Splitter;
	import com.google.common.base.Supplier;
	import com.google.common.collect.ImmutableList;
	import com.google.common.collect.ImmutableMap;
	import com.google.common.collect.ImmutableSet;
	import com.google.jimfs.internal.attribute.AttributeProvider;
	import com.google.jimfs.internal.attribute.AttributeProviderRegistry;
	import com.google.jimfs.internal.file.ArrayByteStore;
	import com.google.jimfs.internal.file.DirectoryTable;
	import com.google.jimfs.internal.file.File;
	import com.google.jimfs.internal.file.FileContent;
	import com.google.jimfs.internal.path.JimfsPath;

	import java.io.IOException;
	import java.nio.file.FileStore;
	import java.nio.file.FileSystem;
	import java.nio.file.Files;
	import java.nio.file.LinkOption;
	import java.nio.file.Path;
	import java.nio.file.attribute.BasicFileAttributes;
	import java.nio.file.attribute.FileAttribute;
	import java.nio.file.attribute.FileAttributeView;
	import java.nio.file.attribute.FileStoreAttributeView;
	import java.util.Arrays;
	import java.util.List;
	import java.util.concurrent.atomic.AtomicLong;

	import javax.annotation.Nullable;

	/**
	* Service for creating and copying files as well as reading and setting attributes on them.
	*
	* @author Colin Decker
	*/
	public final class JimfsFileStore extends FileStore {

	private static final String ALL_ATTRIBUTES = "*";

	private final AtomicLong idGenerator = new AtomicLong();

	private final String name;
	private final AttributeProviderRegistry attributeProviders;

	/** Directory supplier with no extra file attributes. */
	private final Supplier<File> defaultDirectorySupplier = new DirectorySupplier();
	/** Regular file supplier with no extra file attributes. */
	private final Supplier<File> defaultRegularFileSupplier = new RegularFileSupplier();

	/**
	* Creates a new file service using the given providers to handle file attributes.
	*/
	public JimfsFileStore(String name, AttributeProvider... providers) {
	this(name, Arrays.asList(providers));
	}

	/**
	* Creates a new file service using the given providers to handle file attributes.
	*/
	public JimfsFileStore(String name, Iterable<? extends AttributeProvider> providers) {
	this.name = checkNotNull(name);
	this.attributeProviders = new AttributeProviderRegistry(providers);
	}

	@Override
	public String name() {
	return name;
	}

	@Override
	public String type() {
	return "jimfs";
	}

	@Override
	public boolean isReadOnly() {
	return false;
	}

	@Override
	public long getTotalSpace() throws IOException {
	return Integer.MAX_VALUE;
	}

	@Override
	public long getUsableSpace() throws IOException {
	return Integer.MAX_VALUE;
	}

	@Override
	public long getUnallocatedSpace() throws IOException {
	return Integer.MAX_VALUE;
	}

	private long nextFileId() {
	return idGenerator.getAndIncrement();
	}

	private File createFile(long id, FileContent content, FileAttribute<?>... attrs) {
	File file = new File(id, content);
	setInitialAttributes(file);
	for (FileAttribute<?> attr : attrs) {
	setAttributeInternal(file, attr.name(), attr.value(), true);
	}
	return file;
	}

	/**
	* Creates a new directory and stores it. Returns the key of the new file.
	*/
	public File createDirectory(FileAttribute<?>... attrs) {
	return createFile(nextFileId(), new DirectoryTable(), attrs);
	}

	/**
	* Creates a new regular file and stores it. Returns the key of the new file.
	*/
	public File createRegularFile(FileAttribute<?>... attrs) {
	return createFile(nextFileId(), new ArrayByteStore(), attrs);
	}

	/**
	* Creates a new symbolic link referencing the given target path and stores it. Returns the key of
	* the new file.
	*/
	public File createSymbolicLink(JimfsPath target, FileAttribute<?>... attrs) {
	return createFile(nextFileId(), target, attrs);
	}

	/**
	* Creates copies of the given file metadata and content and stores them. Returns the key of the
	* new file.
	*/
	public File copy(File file) {
	return createFile(nextFileId(), file.content().copy());
	}

	/**
	* Returns a supplier that creates directories and sets the given attributes.
	*/
	public Supplier<File> directorySupplier(FileAttribute<?>... attrs) {
	return attrs.length == 0 ? defaultDirectorySupplier : new DirectorySupplier(attrs);
	}

	/**
	* Returns a supplier that creates a regular files and sets the given attributes.
	*/
	public Supplier<File> regularFileSupplier(FileAttribute<?>... attrs) {
	return attrs.length == 0 ? defaultRegularFileSupplier : new RegularFileSupplier(attrs);
	}

	/**
	* Returns a supplier that creates a symbolic links to the given path and sets the given
	* attributes.
	*/
	public Supplier<File> symbolicLinkSupplier(JimfsPath target, FileAttribute<?>... attrs) {
	return new SymbolicLinkSupplier(target, attrs);
	}

	/**
	* Implements {@link FileSystem#supportedFileAttributeViews()}.
	*/
	public ImmutableSet<String> supportedFileAttributeViews() {
	return attributeProviders.getSupportedViews();
	}

	/**
	* Implements {@link FileStore#supportsFileAttributeView(Class)}.
	*/
	public boolean supportsFileAttributeView(Class<? extends FileAttributeView> type) {
	return attributeProviders.getSupportedViewTypes().contains(type);
	}

	@Override
	public boolean supportsFileAttributeView(String name) {
	return supportedFileAttributeViews().contains(name);
	}

	/**
	* Sets all initial attributes for the given file.
	*/
	private void setInitialAttributes(File file) {
	for (AttributeProvider provider : attributeProviders.getProviders()) {
	provider.setInitial(file);
	}
	}

	/**
	* Gets the value of the given attribute for the given file. {@code attribute} must be of the form
	* "view:attribute" or "attribute".
	*/
	public <V> V getAttribute(File file, String attribute) {
	String view = getViewName(attribute);
	String attr = getSingleAttribute(attribute);
	return getAttribute(file, view, attr);
	}

	/**
	* Gets the value of the given attribute for the given view and file. Neither view nor file may
	* have a ':' character.
	*/
	@SuppressWarnings("unchecked")
	public <V> V getAttribute(File file, String view, String attribute) {
	for (AttributeProvider provider : attributeProviders.getProviders(view)) {
	if (provider.isGettable(file, attribute)) {
	return (V) provider.get(file, attribute);
	}
	}

	throw new IllegalArgumentException("attribute not found: " + attribute);
	}

	/**
	* Sets the value of the given attribute to the given value for the given file.
	*/
	public void setAttribute(File file, String attribute, Object value) {
	setAttributeInternal(file, attribute, value, false);
	}

	/**
	* Sets the value of the given attribute to the given value for the given view and file.
	*/
	public void setAttribute(File file, String view, String attribute, Object value) {
	setAttributeInternal(file, view, attribute, value, false);
	}

	private void setAttributeInternal(File file, String attribute, Object value, boolean create) {
	String view = getViewName(attribute);
	String attr = getSingleAttribute(attribute);
	setAttributeInternal(file, view, attr, value, create);
	}

	private void setAttributeInternal(
	File file, String view, String attribute, Object value, boolean create) {
	for (AttributeProvider provider : attributeProviders.getProviders(view)) {
	if (provider.isSettable(file, attribute)) {
	if (create && !provider.isSettableOnCreate(attribute)) {
	throw new UnsupportedOperationException(
	"cannot set attribute '" + view + ":" + attribute + "' during file creation");
	}

	ImmutableSet<Class<?>> acceptedTypes = provider.acceptedTypes(attribute);
	boolean validType = false;
	for (Class<?> type : acceptedTypes) {
	if (type.isInstance(value)) {
	validType = true;
	break;
	}
	}

	if (validType) {
	provider.set(file, attribute, value);
	return;
	} else {
	Object acceptedTypeMessage = acceptedTypes.size() == 1
	? acceptedTypes.iterator().next()
	: "one of " + acceptedTypes;
	throw new IllegalArgumentException("invalid type " + value.getClass()
	+ " for attribute '" + view + ":" + attribute + "': should be "
	+ acceptedTypeMessage);
	}
	}
	}

	throw new IllegalArgumentException("cannot set attribute '" + view + ":" + attribute + "'");
	}

	/**
	* Returns an attribute view of the given type for the given file provider, or {@code null} if the
	* view type is not supported.
	*/
	@Nullable
	public <V extends FileAttributeView> V getFileAttributeView(
	FileProvider fileProvider, Class<V> type) {
	if (supportsFileAttributeView(type)) {
	return attributeProviders.getViewProvider(type).getView(fileProvider);
	}

	return null;
	}

	/**
	* Implements {@link Files#readAttributes(Path, String, LinkOption...)}.
	*/
	public ImmutableMap<String, Object> readAttributes(File file, String attributes) {
	String view = getViewName(attributes);
	List<String> attrs = getAttributeNames(attributes);

	if (attrs.size() > 1 && attrs.contains(ALL_ATTRIBUTES)) {
	// attrs contains * and other attributes
	throw new IllegalArgumentException("invalid attributes: " + attributes);
	}

	ImmutableMap.Builder<String, Object> result = ImmutableMap.builder();
	if (attrs.size() == 1 && attrs.contains(ALL_ATTRIBUTES)) {
	// for 'view:*' format, get all keys for all providers for the view
	for (AttributeProvider provider : attributeProviders.getProviders(view)) {
	provider.readAll(file, result);
	}
	} else {
	// for 'view:attr1,attr2,etc'
	for (String attr : attrs) {
	boolean found = false;
	for (AttributeProvider provider : attributeProviders.getProviders(view)) {
	if (provider.isGettable(file, attr)) {
	result.put(attr, provider.get(file, attr));
	found = true;
	break;
	}
	}

	if (!found) {
	throw new IllegalArgumentException("invalid attribute for view '" + view + "': " + attr);
	}
	}
	}

	return result.build();
	}

	/**
	* Returns attributes of the given file as an object of the given type.
	*
	* @throws UnsupportedOperationException if the given attributes type is not supported
	*/
	public <A extends BasicFileAttributes> A readAttributes(File file, Class<A> type) {
	if (attributeProviders.getSupportedAttributesTypes().contains(type)) {
	return attributeProviders.getReader(type).read(file);
	}

	throw new UnsupportedOperationException("unsupported attributes type: " + type);
	}

	private static String getViewName(String attribute) {
	int separatorIndex = attribute.indexOf(':');

	if (separatorIndex == -1) {
	return "basic";
	}

	// separator must not be at the start or end of the string or appear more than once
	if (separatorIndex == 0
	\|\| separatorIndex == attribute.length() - 1
	\|\| attribute.indexOf(':', separatorIndex + 1) != -1) {
	throw new IllegalArgumentException("illegal attribute format: " + attribute);
	}

	return attribute.substring(0, separatorIndex);
	}

	private static final Splitter ATTRIBUTE_SPLITTER = Splitter.on(',');

	private static ImmutableList<String> getAttributeNames(String attributes) {
	int separatorIndex = attributes.indexOf(':');
	String attributesPart = attributes.substring(separatorIndex + 1);

	return ImmutableList.copyOf(ATTRIBUTE_SPLITTER.split(attributesPart));
	}

	private static String getSingleAttribute(String attribute) {
	ImmutableList<String> attributeNames = getAttributeNames(attribute);

	if (attributeNames.size() != 1 \|\| ALL_ATTRIBUTES.equals(attributeNames.get(0))) {
	throw new IllegalArgumentException("must specify a single attribute: " + attribute);
	}

	return attributeNames.get(0);
	}

	/**
	* Returns {@code null}. This file store does not support any file store attribute views.
	*/
	@Override
	public <V extends FileStoreAttributeView> V getFileStoreAttributeView(Class<V> type) {
	return null;
	}

	/**
	* Throws {@link UnsupportedOperationException}. This file store does not support any file store
	* attributes.
	*/
	@Override
	public Object getAttribute(String attribute) throws IOException {
	throw new UnsupportedOperationException();
	}

	private abstract class FileSupplier implements Supplier<File> {

	protected final FileAttribute<?>[] attrs;

	protected FileSupplier(FileAttribute<?>[] attrs) {
	this.attrs = checkNotNull(attrs);
	}
	}

	private final class DirectorySupplier extends FileSupplier {

	private DirectorySupplier(FileAttribute<?>... attrs) {
	super(attrs);
	}

	@Override
	public File get() {
	return createDirectory(attrs);
	}
	}

	private final class RegularFileSupplier extends FileSupplier {

	private RegularFileSupplier(FileAttribute<?>... attrs) {
	super(attrs);
	}

	@Override
	public File get() {
	return createRegularFile(attrs);
	}
	}

	private final class SymbolicLinkSupplier extends FileSupplier {

	private final JimfsPath target;

	protected SymbolicLinkSupplier(JimfsPath target, FileAttribute<?>... attrs) {
	super(attrs);
	this.target = checkNotNull(target);
	}

	@Override
	public File get() {
	return createSymbolicLink(target, attrs);
	}
	}
	}