/*
* 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.common.jimfs;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.base.Objects;
import java.nio.file.FileAlreadyExistsException;
import java.nio.file.NoSuchFileException;
import java.nio.file.NotDirectoryException;
import java.nio.file.NotLinkException;
import java.nio.file.Path;
import javax.annotation.Nullable;
/**
* Entry in a directory, containing references to the directory itself, the file the entry links to
* and the name of the entry.
*
* <p>May also represent a non-existent entry if the name does not link to any file in the
* directory.
*/
final class DirectoryEntry {
private final Directory directory;
private final Name name;
@Nullable
private final File file;
@Nullable
DirectoryEntry next; // for use in Directory
DirectoryEntry(Directory directory, Name name, @Nullable File file) {
this.directory = checkNotNull(directory);
this.name = checkNotNull(name);
this.file = file;
}
/**
* Returns {@code true} if and only if this entry represents an existing file.
*/
public boolean exists() {
return file != null;
}
/**
* Checks that this entry exists, throwing an exception if not.
*
* @return this
* @throws NoSuchFileException if this entry does not exist
*/
public DirectoryEntry requireExists(Path pathForException) throws NoSuchFileException {
if (!exists()) {
throw new NoSuchFileException(pathForException.toString());
}
return this;
}
/**
* Checks that this entry does not exist, throwing an exception if it does.
*
* @return this
* @throws FileAlreadyExistsException if this entry does not exist
*/
public DirectoryEntry requireDoesNotExist(
Path pathForException) throws FileAlreadyExistsException {
if (exists()) {
throw new FileAlreadyExistsException(pathForException.toString());
}
return this;
}
/**
* Checks that this entry exists and links to a directory, throwing an exception if not.
*
* @return this
* @throws NoSuchFileException if this entry does not exist
* @throws NotDirectoryException if this entry does not link to a directory
*/
public DirectoryEntry requireDirectory(
Path pathForException) throws NoSuchFileException, NotDirectoryException {
requireExists(pathForException);
if (!file().isDirectory()) {
throw new NotDirectoryException(pathForException.toString());
}
return this;
}
/**
* Checks that this entry exists and links to a symbolic link, throwing an exception if not.
*
* @return this
* @throws NoSuchFileException if this entry does not exist
* @throws NotLinkException if this entry does not link to a symbolic link
*/
public DirectoryEntry requireSymbolicLink(
Path pathForException) throws NoSuchFileException, NotLinkException {
requireExists(pathForException);
if (!file().isSymbolicLink()) {
throw new NotLinkException(pathForException.toString());
}
return this;
}
/**
* Returns the directory containing this entry.
*/
public Directory directory() {
return directory;
}
/**
* Returns the name of this entry.
*/
public Name name() {
return name;
}
/**
* Returns the file this entry links to.
*
* @throws IllegalStateException if the file does not exist
*/
public File file() {
checkState(exists());
return file;
}
/**
* Returns the file this entry links to or {@code null} if the file does not exist
*/
@Nullable
public File fileOrNull() {
return file;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof DirectoryEntry) {
DirectoryEntry other = (DirectoryEntry) obj;
return directory.equals(other.directory)
&& name.equals(other.name)
&& Objects.equal(file, other.file);
}
return false;
}
@Override
public int hashCode() {
return Objects.hashCode(directory, name, file);
}
@Override
public String toString() {
return Objects.toStringHelper(this)
.add("directory", directory)
.add("name", name)
.add("file", file)
.toString();
}
}