/*

 * Copyright 2007-2009 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package java.nio.file;

import java.nio.file.attribute.*;

import java.util.Map;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.IOException;

/**

 * A reference to a file.

 *

 * <p> A {@code FileRef} is an object that locates a file and defines methods to

 * open the file for reading or writing. It also provides access to associated

 * metadata or file attributes.

 *

 * @since 1.7

 * @see java.nio.file.attribute.Attributes

 * @see java.io.File#toPath

 */

public interface FileRef {

    /**

     * Opens the file referenced by this object, returning an input stream to

     * read from the file. The stream will not be buffered, and is not required

     * to support the {@link InputStream#mark mark} or {@link InputStream#reset

     * reset} methods. The stream will be safe for access by multiple concurrent

     * threads. Reading commences at the beginning of the file.

     *

     * <p> The {@code options} parameter determines how the file is opened.

     * If no options are present then it is equivalent to opening the file with

     * the {@link StandardOpenOption#READ READ} option. In addition to the {@code

     * READ} option, an implementation may also support additional implementation

     * specific options.

     *

     * @return  an input stream to read bytes from the file

     *

     * @throws  IllegalArgumentException

     *          if an invalid combination of options is specified

     * @throws  UnsupportedOperationException

     *          if an unsupported option is specified

     * @throws  IOException

     *          if an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, the {@link SecurityManager#checkRead(String) checkRead}

     *          method is invoked to check read access to the file.

     */

    InputStream newInputStream(OpenOption... options) throws IOException;

    /**

     * Opens or creates the file located by this object for writing, returning

     * an output stream to write bytes to the file.

     *

     * <p> The {@code options} parameter determines how the file is opened.

     * If no options are present then this method creates a new file for writing

     * or truncates an existing file. In addition to the {@link StandardOpenOption

     * standard} options, an implementation may also support additional

     * implementation specific options.

     *

     * <p> The resulting stream will not be buffered. The stream will be safe

     * for access by multiple concurrent threads.

     *

     * @param   options

     *          options specifying how the file is opened

     *

     * @return  a new output stream

     *

     * @throws  IllegalArgumentException

     *          if {@code options} contains an invalid combination of options

     * @throws  UnsupportedOperationException

     *          if an unsupported option is specified

     * @throws  IOException

     *          if an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, the {@link SecurityManager#checkWrite(String) checkWrite}

     *          method is invoked to check write access to the file.

     */

    OutputStream newOutputStream(OpenOption... options) throws IOException;

    /**

     * Returns a file attribute view of a given type.

     *

     * <p> A file attribute view provides a read-only or updatable view of a

     * set of file attributes. This method is intended to be used where the file

     * attribute view defines type-safe methods to read or update the file

     * attributes. The {@code type} parameter is the type of the attribute view

     * required and the method returns an instance of that type if supported.

     * The {@link BasicFileAttributeView} type supports access to the basic

     * attributes of a file. Invoking this method to select a file attribute

     * view of that type will always return an instance of that class.

     *

     * <p> The {@code options} array may be used to indicate how symbolic links

     * are handled by the resulting file attribute view for the case that the

     * file is a symbolic link. By default, symbolic links are followed. If the

     * option {@link LinkOption#NOFOLLOW_LINKS NOFOLLOW_LINKS} is present then

     * symbolic links are not followed. This option is ignored by implementations

     * that do not support symbolic links.

     *

     * @param   type

     *          the {@code Class} object corresponding to the file attribute view

     * @param   options

     *          options indicating how symbolic links are handled

     *

     * @return  a file attribute view of the specified type, or {@code null} if

     *          the attribute view type is not available

     *

     * @throws  UnsupportedOperationException

     *          If options contains an unsupported option. This exception is

     *          specified to allow the {@code LinkOption} enum be extended

     *          in future releases.

     *

     * @see Attributes#readBasicFileAttributes

     */

    <V extends FileAttributeView> V getFileAttributeView(Class<V> type,

                                                         LinkOption... options);

    /**

     * Sets the value of a file attribute.

     *

     * <p> The {@code attribute} parameter identifies the attribute to be set

     * and takes the form:

     * <blockquote>

     * [<i>view-name</i><b>:</b>]<i>attribute-name</i>

     * </blockquote>

     * where square brackets [...] delineate an optional component and the

     * character {@code ':'} stands for itself.

     *

     * <p> <i>view-name</i> is the {@link FileAttributeView#name name} of a {@link

     * FileAttributeView} that identifies a set of file attributes. If not

     * specified then it defaults to {@code "basic"}, the name of the file

     * attribute view that identifies the basic set of file attributes common to

     * many file systems. <i>attribute-name</i> is the name of the attribute

     * within the set.

     *

     * <p> <b>Usage Example:</b>

     * Suppose we want to set the DOS "hidden" attribute:

     * <pre>

     *    file.setAttribute("dos:hidden", true);

     * </pre>

     *

     * @param   attribute

     *          the attribute to set

     * @param   value

     *          the attribute value

     * @param   options

     *          options indicating how symbolic links are handled

     *

     * @throws  UnsupportedOperationException

     *          if the attribute view is not available or it does not support

     *          updating the attribute

     * @throws  IllegalArgumentException

     *          if the attribute value is of the correct type but has an

     *          inappropriate value

     * @throws  ClassCastException

     *          If the attribute value is not of the expected type or is a

     *          collection containing elements that are not of the expected

     *          type

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, its {@link SecurityManager#checkWrite(String) checkWrite}

     *          method denies write access to the file. If this method is invoked

     *          to set security sensitive attributes then the security manager

     *          may be invoked to check for additional permissions.

     */

    void setAttribute(String attribute, Object value, LinkOption... options)

        throws IOException;

    /**

     * Reads the value of a file attribute.

     *

     * <p> The {@code attribute} parameter identifies the attribute to be read

     * and takes the form:

     * <blockquote>

     * [<i>view-name</i><b>:</b>]<i>attribute-name</i>

     * </blockquote>

     * where square brackets [...] delineate an optional component and the

     * character {@code ':'} stands for itself.

     *

     * <p> <i>view-name</i> is the {@link FileAttributeView#name name} of a {@link

     * FileAttributeView} that identifies a set of file attributes. If not

     * specified then it defaults to {@code "basic"}, the name of the file

     * attribute view that identifies the basic set of file attributes common to

     * many file systems. <i>attribute-name</i> is the name of the attribute.

     *

     * <p> The {@code options} array may be used to indicate how symbolic links

     * are handled for the case that the file is a symbolic link. By default,

     * symbolic links are followed and the file attribute of the final target

     * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS

     * NOFOLLOW_LINKS} is present then symbolic links are not followed and so

     * the method returns the file attribute of the symbolic link.

     *

     * <p> <b>Usage Example:</b>

     * Suppose we require the user ID of the file owner on a system that

     * supports a "{@code unix}" view:

     * <pre>

     *    int uid = (Integer)file.getAttribute("unix:uid");

     * </pre>

     *

     * @param   attribute

     *          the attribute to read

     * @param   options

     *          options indicating how symbolic links are handled

     * @return  the attribute value or {@code null} if the attribute view

     *          is not available or it does not support reading the attribute

     *

     *          reading the attribute

     * @throws  IOException

     *          if an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, its {@link SecurityManager#checkRead(String) checkRead}

     *          method denies read access to the file. If this method is invoked

     *          to read security sensitive attributes then the security manager

     *          may be invoked to check for additional permissions.

     */

    Object getAttribute(String attribute, LinkOption... options) throws IOException;

    /**

     * Reads a set of file attributes as a bulk operation.

     *

     * <p> The {@code attributes} parameter identifies the attributes to be read

     * and takes the form:

     * <blockquote>

     * [<i>view-name</i><b>:</b>]<i>attribute-list</i>

     * </blockquote>

     * where square brackets [...] delineate an optional component and the

     * character {@code ':'} stands for itself.

     *

     * <p> <i>view-name</i> is the {@link FileAttributeView#name name} of a {@link

     * FileAttributeView} that identifies a set of file attributes. If not

     * specified then it defaults to {@code "basic"}, the name of the file

     * attribute view that identifies the basic set of file attributes common to

     * many file systems.

     *

     * <p> The <i>attribute-list</i> component is a comma separated list of

     * zero or more names of attributes to read. If the list contains the value

     * {@code "*"} then all attributes are read. Attributes that are not supported

     * are ignored and will not be present in the returned map. It is

     * implementation specific if all attributes are read as an atomic operation

     * with respect to other file system operations.

     *

     * <p> The following examples demonstrate possible values for the {@code

     * attributes} parameter:

     *

     * <blockquote>

     * <table border="0">

     * <tr>

     *   <td> {@code "*"} </td>

     *   <td> Read all {@link BasicFileAttributes basic-file-attributes}. </td>

     * </tr>

     * <tr>

     *   <td> {@code "size,lastModifiedTime,lastAccessTime"} </td>

     *   <td> Reads the file size, last modified time, and last access time

     *     attributes. </td>

     * </tr>

     * <tr>

     *   <td> {@code "posix:*"} </td>

     *   <td> Read all {@link PosixFileAttributes POSIX-file-attributes}.. </td>

     * </tr>

     * <tr>

     *   <td> {@code "posix:permissions,owner,size"} </td>

     *   <td> Reads the POSX file permissions, owner, and file size. </td>

     * </tr>

     * </table>

     * </blockquote>

     *

     * <p> The {@code options} array may be used to indicate how symbolic links

     * are handled for the case that the file is a symbolic link. By default,

     * symbolic links are followed and the file attribute of the final target

     * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS

     * NOFOLLOW_LINKS} is present then symbolic links are not followed and so

     * the method returns the file attribute of the symbolic link.

     *

     * @param   attributes

     *          The attributes to read

     * @param   options

     *          Options indicating how symbolic links are handled

     *

     * @return  A map of the attributes returned; may be empty. The map's keys

     *          are the attribute names, its values are the attribute values

     *

     * @throws  IOException

     *          If an I/O error occurs

     * @throws  SecurityException

     *          In the case of the default provider, and a security manager is

     *          installed, its {@link SecurityManager#checkRead(String) checkRead}

     *          method denies read access to the file. If this method is invoked

     *          to read security sensitive attributes then the security manager

     *          may be invoke to check for additional permissions.

     */

    Map<String,?> readAttributes(String attributes, LinkOption... options)

        throws IOException;

}