/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.resources;

import java.io.InputStream;
import java.io.Reader;
import java.net.URI;
import org.eclipse.core.runtime.*;
import org.eclipse.core.runtime.content.IContentDescription;
import org.eclipse.core.runtime.content.IContentTypeManager;

/**
 * Files are leaf resources which contain data.
 * The contents of a file resource is stored as a file in the local
 * file system.
 * <p>
 * Files, like folders, may exist in the workspace but
 * not be local; non-local file resources serve as place-holders for
 * files whose content and properties have not yet been fetched from
 * a repository.
 * </p>
 * <p>
 * Files implement the <code>IAdaptable</code> interface;
 * extensions are managed by the platform's adapter manager.
 * </p>
 *
 * @see Platform#getAdapterManager()
 * @noimplement This interface is not intended to be implemented by clients.
 */
public interface IFile extends IResource, IEncodedStorage, IAdaptable {
	/**
	 * Character encoding constant (value 0) which identifies
	 * files that have an unknown character encoding scheme.
	 * 
	 * @see IFile#getEncoding()
	 * @deprecated see getEncoding for details
	 */
	public int ENCODING_UNKNOWN = 0;
	/**
	 * Character encoding constant (value 1) which identifies
	 * files that are encoded with the US-ASCII character encoding scheme.
	 * 
	 * @see IFile#getEncoding()
	 * @deprecated see getEncoding for details 
	 */
	public int ENCODING_US_ASCII = 1;
	/**
	 * Character encoding constant (value 2) which identifies
	 * files that are encoded with the ISO-8859-1 character encoding scheme,
	 * also known as ISO-LATIN-1.
	 * 
	 * @see IFile#getEncoding()
	 * @deprecated see getEncoding for details
	 */
	public int ENCODING_ISO_8859_1 = 2;
	/**
	 * Character encoding constant (value 3) which identifies
	 * files that are encoded with the UTF-8 character encoding scheme.
	 * 
	 * @see IFile#getEncoding()
	 * @deprecated see getEncoding for details
	 */
	public int ENCODING_UTF_8 = 3;
	/**
	 * Character encoding constant (value 4) which identifies
	 * files that are encoded with the UTF-16BE character encoding scheme.
	 * 
	 * @see IFile#getEncoding()
	 * @deprecated see getEncoding for details
	 */
	public int ENCODING_UTF_16BE = 4;
	/**
	 * Character encoding constant (value 5) which identifies
	 * files that are encoded with the UTF-16LE character encoding scheme.
	 * 
	 * @see IFile#getEncoding()
	 * @deprecated see getEncoding for details
	 */
	public int ENCODING_UTF_16LE = 5;
	/**
	 * Character encoding constant (value 6) which identifies
	 * files that are encoded with the UTF-16 character encoding scheme.
	 * 
	 * @see IFile#getEncoding()
	 * @deprecated see getEncoding for details
	 */
	public int ENCODING_UTF_16 = 6;

	/**
	 * Appends the entire contents of the given stream to this file.
	 * <p>
	 * This is a convenience method, fully equivalent to:
	 * <pre>
	 *   appendContents(source, (keepHistory ? KEEP_HISTORY : IResource.NONE) | (force ? FORCE : IResource.NONE), monitor);
	 * </pre>
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that this file's content have been changed.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancelation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param source an input stream containing the new contents of the file
	 * @param force a flag controlling how to deal with resources that
	 *    are not in sync with the local file system
	 * @param keepHistory a flag indicating whether or not to store
	 *    the current contents in the local history
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * <li> The workspace is not in sync with the corresponding location
	 *       in the local file system and <code>force </code> is <code>false</code>.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * <li> The file modification validator disallowed the change.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see #appendContents(java.io.InputStream,int,IProgressMonitor)
	 */
	public void appendContents(InputStream source, boolean force, boolean keepHistory, IProgressMonitor monitor) throws CoreException;

	/**
	 * Appends the entire contents of the given stream to this file.
	 * The stream, which must not be <code>null</code>, will get closed 
	 * whether this method succeeds or fails.
	 * <p>
	 * The <code>FORCE</code> update flag controls how this method deals with
	 * cases where the workspace is not completely in sync with the local file 
	 * system. If <code>FORCE</code> is not specified, the method will only attempt
	 * to overwrite a corresponding file in the local file system provided
	 * it is in sync with the workspace. This option ensures there is no 
	 * unintended data loss; it is the recommended setting.
	 * However, if <code>FORCE</code> is specified, an attempt will be made
	 * to write a corresponding file in the local file system, overwriting any
	 * existing one if need be. In either case, if this method succeeds, the 
	 * resource will be marked as being local (even if it wasn't before).
	 * </p>
	 * <p>
	 * If this file is non-local then this method will always fail. The only exception
	 * is when <code>FORCE</code> is specified and the file exists in the local 
	 * file system. In this case the file is made local and the given contents are appended.
	 * </p>
	 * <p>
	 * The <code>KEEP_HISTORY</code> update flag controls whether or not a copy of
	 * current contents of this file should be captured in the workspace's local
	 * history (properties are not recorded in the local history). The local history
	 * mechanism serves as a safety net to help the user recover from mistakes that
	 * might otherwise result in data loss. Specifying <code>KEEP_HISTORY</code>
	 * is recommended except in circumstances where past states of the files are of
	 * no conceivable interest to the user. Note that local history is maintained
	 * with each individual project, and gets discarded when a project is deleted
	 * from the workspace. This flag is ignored if the file was not previously local.
	 * </p>
	 * <p>
	 * Update flags other than <code>FORCE</code> and <code>KEEP_HISTORY</code> 
	 * are ignored.
	 * </p>
	 * <p>
	 * Prior to modifying the contents of this file, the file modification validator (if provided 
	 * by the VCM plug-in), will be given a chance to perform any last minute preparations.  Validation
	 * is performed by calling <code>IFileModificationValidator.validateSave</code> on this file.
	 * If the validation fails, then this operation will fail.
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that this file's content have been changed.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancelation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param source an input stream containing the new contents of the file
	 * @param updateFlags bit-wise or of update flag constants
	 *   (<code>FORCE</code> and <code>KEEP_HISTORY</code>)
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * <li> The workspace is not in sync with the corresponding location
	 *       in the local file system and <code>FORCE</code> is not specified.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * <li> The file modification validator disallowed the change.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see IResourceRuleFactory#modifyRule(IResource)
	 * @since 2.0
	 */
	public void appendContents(InputStream source, int updateFlags, IProgressMonitor monitor) throws CoreException;

	/**
	 * Creates a new file resource as a member of this handle's parent resource.
	 * <p>
	 * This is a convenience method, fully equivalent to:
	 * <pre>
	 *   create(source, (force ? FORCE : IResource.NONE), monitor);
	 * </pre>
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that the file has been added to its parent.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param source an input stream containing the initial contents of the file,
	 *    or <code>null</code> if the file should be marked as not local
	 * @param force a flag controlling how to deal with resources that
	 *    are not in sync with the local file system
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource already exists in the workspace.</li>
	 * <li> The parent of this resource does not exist.</li>
	 * <li> The project of this resource is not accessible.</li>
	 * <li> The parent contains a resource of a different type 
	 *      at the same path as this resource.</li>
	 * <li> The name of this resource is not valid (according to 
	 *    <code>IWorkspace.validateName</code>).</li>
	 * <li> The corresponding location in the local file system is occupied
	 *    by a directory.</li>
	 * <li> The corresponding location in the local file system is occupied
	 *    by a file and <code>force </code> is <code>false</code>.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 */
	public void create(InputStream source, boolean force, IProgressMonitor monitor) throws CoreException;

	/**
	 * Creates a new file resource as a member of this handle's parent resource.
	 * The resource's contents are supplied by the data in the given stream.
	 * This method closes the stream whether it succeeds or fails.
	 * If the stream is <code>null</code> then a file is not created in the local
	 * file system and the created file resource is marked as being non-local.
	 * <p>
	 * The {@link IResource#FORCE} update flag controls how this method deals with
	 * cases where the workspace is not completely in sync with the local file 
	 * system. If {@link IResource#FORCE} is not specified, the method will only attempt
	 * to write a file in the local file system if it does not already exist. 
	 * This option ensures there is no unintended data loss; it is the recommended
	 * setting. However, if {@link IResource#FORCE} is specified, this method will 
	 * attempt to write a corresponding file in the local file system, 
	 * overwriting any existing one if need be.
	 * </p>
	 * <p>
	 * The {@link IResource#DERIVED} update flag indicates that this resource
	 * should immediately be set as a derived resource.  Specifying this flag
	 * is equivalent to atomically calling {@link IResource#setDerived(boolean)}
	 * with a value of <code>true</code> immediately after creating the resource.
	 * </p>
	 * <p>
	 * The {@link IResource#TEAM_PRIVATE} update flag indicates that this resource
	 * should immediately be set as a team private resource.  Specifying this flag
	 * is equivalent to atomically calling {@link IResource#setTeamPrivateMember(boolean)}
	 * with a value of <code>true</code> immediately after creating the resource.
	 * </p>
	 * <p>
	 * Update flags other than those listed above are ignored.
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that the file has been added to its parent.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param source an input stream containing the initial contents of the file,
	 *    or <code>null</code> if the file should be marked as not local
	 * @param updateFlags bit-wise or of update flag constants
	 *   ({@link IResource#FORCE}, {@link IResource#DERIVED}, and {@link IResource#TEAM_PRIVATE})
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource already exists in the workspace.</li>
	 * <li> The parent of this resource does not exist.</li>
	 * <li> The project of this resource is not accessible.</li>
	 * <li> The parent contains a resource of a different type 
	 *      at the same path as this resource.</li>
	 * <li> The name of this resource is not valid (according to 
	 *    <code>IWorkspace.validateName</code>).</li>
	 * <li> The corresponding location in the local file system is occupied
	 *    by a directory.</li>
	 * <li> The corresponding location in the local file system is occupied
	 *    by a file and <code>FORCE</code> is not specified.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see IResourceRuleFactory#createRule(IResource)
	 * @since 2.0
	 */
	public void create(InputStream source, int updateFlags, IProgressMonitor monitor) throws CoreException;

	/**
	 * Creates a new file resource as a member of this handle's parent resource.
	 * The file's contents will be located in the file specified by the given
	 * file system path.  The given path must be either an absolute file system
	 * path, or a relative path whose first segment is the name of a workspace path
	 * variable.
	 * <p>
	 * The {@link IResource#ALLOW_MISSING_LOCAL} update flag controls how this 
	 * method deals with cases where the local file system file to be linked does
	 * not exist, or is relative to a workspace path variable that is not defined.
	 * If {@link IResource#ALLOW_MISSING_LOCAL} is specified, the operation will succeed
	 * even if the local file is missing, or the path is relative to an undefined
	 * variable. If {@link IResource#ALLOW_MISSING_LOCAL} is not specified, the operation
	 * will fail in the case where the local file system file does not exist or the
	 * path is relative to an undefined variable.
	 * </p>
	 * <p>
	 * The {@link IResource#REPLACE} update flag controls how this 
	 * method deals with cases where a resource of the same name as the 
	 * prospective link already exists. If {@link IResource#REPLACE}
	 * is specified, then any existing resource with the same name is removed
	 * from the workspace to make way for creation of the link.  This does <b>not</b>
	 * cause the underlying file system contents of that resource to be deleted.
	 * If {@link IResource#REPLACE} is not specified, this method will
	 * fail if an existing resource exists of the same name.
	 * </p>
	 * <p>
	 * Update flags other than {@link IResource#ALLOW_MISSING_LOCAL} or
	 * {@link IResource#REPLACE} are ignored.
	 * </p>
	 * <p>
	 * This method synchronizes this resource with the local file system at the given
	 * location.
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that the file has been added to its parent.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param localLocation a file system path where the file should be linked 
	 * @param updateFlags bit-wise or of update flag constants
	 *   ({@link IResource#ALLOW_MISSING_LOCAL} and {@link IResource#REPLACE})
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource already exists in the workspace.</li>
	 * <li> The workspace contains a resource of a different type 
	 *      at the same path as this resource.</li>
	 * <li> The parent of this resource does not exist.</li>
	 * <li> The parent of this resource is not an open project</li>
	 * <li> The name of this resource is not valid (according to 
	 *    <code>IWorkspace.validateName</code>).</li>
	 * <li> The corresponding location in the local file system does not exist, or
	 * is relative to an undefined variable, and <code>ALLOW_MISSING_LOCAL</code> is
	 * not specified.</li>
	 * <li> The corresponding location in the local file system is occupied
	 *    by a directory (as opposed to a file).</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification.  See <code>IResourceChangeEvent</code> for more details.</li>
	 * <li>The team provider for the project which contains this folder does not permit
	 *       linked resources.</li>
	 * <li>This folder's project contains a nature which does not permit linked resources.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see IResource#isLinked()
	 * @see IResource#ALLOW_MISSING_LOCAL
	 * @since 2.1
	 */
	public void createLink(IPath localLocation, int updateFlags, IProgressMonitor monitor) throws CoreException;

	/**
	 * Creates a new file resource as a member of this handle's parent resource.
	 * The file's contents will be located in the file specified by the given
	 * URI.  The given URI must be either absolute, or a relative URI whose first path
	 * segment is the name of a workspace path variable.
	 * <p>
	 * The <code>ALLOW_MISSING_LOCAL</code> update flag controls how this 
	 * method deals with cases where the file system file to be linked does
	 * not exist, or is relative to a workspace path variable that is not defined.
	 * If <code>ALLOW_MISSING_LOCAL</code> is specified, the operation will succeed
	 * even if the local file is missing, or the path is relative to an undefined
	 * variable. If <code>ALLOW_MISSING_LOCAL</code> is not specified, the operation
	 * will fail in the case where the file system file does not exist or the
	 * path is relative to an undefined variable.
	 * </p>
	 * <p>
	 * The {@link IResource#REPLACE} update flag controls how this 
	 * method deals with cases where a resource of the same name as the 
	 * prospective link already exists. If {@link IResource#REPLACE}
	 * is specified, then any existing resource with the same name is removed
	 * from the workspace to make way for creation of the link.  This does <b>not</b>
	 * cause the underlying file system contents of that resource to be deleted.
	 * If {@link IResource#REPLACE} is not specified, this method will
	 * fail if an existing resource exists of the same name.
	 * </p>
	 * <p>
	 * Update flags other than {@link IResource#ALLOW_MISSING_LOCAL} or
	 * {@link IResource#REPLACE} are ignored.
	 * </p>
	 * <p>
	 * This method synchronizes this resource with the file system at the given
	 * location.
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that the file has been added to its parent.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param location a file system URI where the file should be linked 
	 * @param updateFlags bit-wise or of update flag constants
	 *   ({@link IResource#ALLOW_MISSING_LOCAL} and {@link IResource#REPLACE})
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource already exists in the workspace.</li>
	 * <li> The workspace contains a resource of a different type 
	 *      at the same path as this resource.</li>
	 * <li> The parent of this resource does not exist.</li>
	 * <li> The parent of this resource is not an open project</li>
	 * <li> The name of this resource is not valid (according to 
	 *    <code>IWorkspace.validateName</code>).</li>
	 * <li> The corresponding location in the file system does not exist, or
	 * is relative to an undefined variable, and <code>ALLOW_MISSING_LOCAL</code> is
	 * not specified.</li>
	 * <li> The corresponding location in the file system is occupied
	 *    by a directory (as opposed to a file).</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification.  See <code>IResourceChangeEvent</code> for more details.</li>
	 * <li>The team provider for the project which contains this folder does not permit
	 *       linked resources.</li>
	 * <li>This folder's project contains a nature which does not permit linked resources.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see IResource#isLinked()
	 * @see IResource#ALLOW_MISSING_LOCAL
	 * @since 3.2
	 */
	public void createLink(URI location, int updateFlags, IProgressMonitor monitor) throws CoreException;

	/**
	 * Deletes this file from the workspace.
	 * <p>
	 * This is a convenience method, fully equivalent to:
	 * <pre>
	 *   delete((keepHistory ? KEEP_HISTORY : IResource.NONE) | (force ? FORCE : IResource.NONE), monitor);
	 * </pre>
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that this folder has been removed from its parent.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 * 
	 * @param force a flag controlling whether resources that are not
	 *    in sync with the local file system will be tolerated
	 * @param keepHistory a flag controlling whether files under this folder
	 *    should be stored in the workspace's local history
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource could not be deleted for some reason.</li>
	 * <li> This resource is out of sync with the local file system
	 *      and <code>force</code> is <code>false</code>.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see IResource#delete(int,IProgressMonitor)
	 * @see IResourceRuleFactory#deleteRule(IResource)
	 */
	public void delete(boolean force, boolean keepHistory, IProgressMonitor monitor) throws CoreException;

	/**
	 * Returns the name of a charset to be used when decoding the contents of this 
	 * file into characters. 
	 * <p>
	 * This refinement of the corresponding {@link IEncodedStorage} method
	 * is a convenience method, fully equivalent to:
	 * <pre>
	 *   getCharset(true);
	 * </pre>
	 * </p><p>
	 * <b>Note 1</b>:  this method does not check whether the result is a supported
	 * charset name. Callers should be prepared to handle 
	 * <code>UnsupportedEncodingException</code> where this charset is used. 
	 * </p>
	 * <p>
	 * <b>Note 2</b>: this method returns a cached value for the encoding
	 * that may be out of date if the file is not synchronized with the local file system
	 * and the encoding has since changed in the file system.
	 * </p>
	 *  
	 * @return the name of a charset
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource could not be read.</li>
	 * <li> This resource is not local.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * </ul>
	 * @see IFile#getCharset(boolean) 
	 * @see IEncodedStorage#getCharset()
	 * @see IContainer#getDefaultCharset()
	 * @since 3.0
	 */
	public String getCharset() throws CoreException;

	/**
	 * Returns the name of a charset to be used when decoding the contents of this 
	 * file into characters. 
	 * <p>
	 * If checkImplicit is <code>false</code>, this method will return the 
	 * charset defined by calling <code>setCharset</code>, provided this file 
	 * exists, or <code>null</code> otherwise.
	 * </p><p>
	 * If checkImplicit is <code>true</code>, this method uses the following 
	 * algorithm to determine the charset to be returned:
	 * <ol>
	 * <li>the charset defined by calling #setCharset, if any, and this file 
	 * exists, or</li>
	 * <li>the charset automatically discovered based on this file's contents,
	 * if one can be determined, or</li>
	 * <li>the default encoding for this file's parent (as defined by 
	 * <code>IContainer#getDefaultCharset</code>).</li>
	 * </ol>
	 * </p><p>
	 * <b>Note 1</b>:  this method does not check whether the result is a supported
	 * charset name. Callers should be prepared to handle 
	 * <code>UnsupportedEncodingException</code> where this charset is used. 
	 * </p>
	 * <p>
	 * <b>Note 2</b>: this method returns a cached value for the encoding
	 * that may be out of date if the file is not synchronized with the local file system
	 * and the encoding has since changed in the file system.
	 * </p>
	 *  
	 * @return the name of a charset, or <code>null</code>
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource could not be read.</li>
	 * <li> This resource is not local.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * </ul>
	 * @see IEncodedStorage#getCharset()
	 * @see IContainer#getDefaultCharset()
	 * @since 3.0
	 */
	public String getCharset(boolean checkImplicit) throws CoreException;
	
	/**
	 * Returns the name of a charset to be used to encode the given contents 
	 * when saving to this file. This file does not have to exist. The character stream is <em>not</em> automatically closed.   
	 * <p>
	 * This method uses the following algorithm to determine the charset to be returned:
	 * <ol>
	 * <li>if this file exists, the charset returned by IFile#getCharset(false), if one is defined, or</li>
	 * <li>the charset automatically discovered based on the file name and the given contents,
	 * if one can be determined, or</li>
	 * <li>the default encoding for the parent resource (as defined by 
	 * <code>IContainer#getDefaultCharset</code>).</li>
	 * </ol>
	 * </p><p>
	 * <b>Note</b>:  this method does not check whether the result is a supported
	 * charset name. Callers should be prepared to handle 
	 * <code>UnsupportedEncodingException</code> where this charset is used. 
	 * </p>
	 * 
	 * @param reader a character stream containing the contents to be saved into this file
	 * @return the name of a charset
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li>The given character stream could not be read.</li>
	 * </ul>
	 * @see #getCharset(boolean)
	 * @see IContainer#getDefaultCharset()
	 * @since 3.1
	 */
	public String getCharsetFor(Reader reader) throws CoreException;

	/**
	 * Returns a description for this file's current contents. Returns 
	 * <code>null</code> if a description cannot be obtained.
	 * <p>
	 * Calling this method produces a similar effect as calling
	 * <code>getDescriptionFor(getContents(), getName(), IContentDescription.ALL)</code> 
	 * on <code>IContentTypeManager</code>, but provides better 
	 * opportunities for improved performance. Therefore, when manipulating 
	 * <code>IFile</code>s, clients should call this method instead of 
	 * <code>IContentTypeManager.getDescriptionFor</code>. 
	 * </p>
	 *  
	 * @return a description for this file's current contents, or 
	 * <code>null</code>
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> This resource could not be read.</li>
	 * <li> This resource is not local.</li>
	 * <li> The workspace is not in sync with the corresponding location
	 *       in the local file system.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * </ul> 
	 * @see IContentDescription
	 * @see IContentTypeManager#getDescriptionFor(InputStream, String, QualifiedName[])
	 * @since 3.0
	 */
	public IContentDescription getContentDescription() throws CoreException;

	/**
	 * Returns an open input stream on the contents of this file.
	 * This refinement of the corresponding <code>IStorage</code> method 
	 * returns an open input stream on the contents of this file.
	 * The client is responsible for closing the stream when finished.
	 *
	 * @return an input stream containing the contents of the file
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> This resource is not local.</li>
	 * <li> The workspace is not in sync with the corresponding location
	 *       in the local file system.</li>
	 * </ul>
	 */
	public InputStream getContents() throws CoreException;

	/**
	 * This refinement of the corresponding <code>IStorage</code> method 
	 * returns an open input stream on the contents of this file.
	 * The client is responsible for closing the stream when finished.
	 * If force is <code>true</code> the file is opened and an input
	 * stream returned regardless of the sync state of the file. The file
	 * is not synchronized with the workspace.
	 * If force is <code>false</code> the method fails if not in sync.
	 *
	 * @param force a flag controlling how to deal with resources that
	 *    are not in sync with the local file system
	 * @return an input stream containing the contents of the file
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> This resource is not local.</li>
	 * <li> The workspace is not in sync with the corresponding location
	 *       in the local file system and force is <code>false</code>.</li>
	 * </ul>
	 */
	public InputStream getContents(boolean force) throws CoreException;

	/**
	 * Returns a constant identifying the character encoding of this file, or 
	 * ENCODING_UNKNOWN if it could not be determined.  The returned constant
	 * will be one of the ENCODING_* constants defined on IFile.
	 * 
	 * This method attempts to guess the file's character encoding by analyzing
	 * the first few bytes of the file.  If no identifying pattern is found at the 
	 * beginning of the file, ENC_UNKNOWN will be returned.  This method will
	 * not attempt any complex analysis of the file to make a guess at the 
	 * encoding that is used.
	 * 
	 * @return The character encoding of this file
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> This resource could not be read.</li>
	 * <li> This resource is not local.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * </ul>
	 * @deprecated use IFile#getCharset instead
	 */
	public int getEncoding() throws CoreException;

	/**
	 * Returns the full path of this file. 
	 * This refinement of the corresponding <code>IStorage</code> and <code>IResource</code>
	 * methods links the semantics of resource and storage object paths such that
	 * <code>IFile</code>s always have a path and that path is relative to the
	 * containing workspace.
	 *
	 * @see IResource#getFullPath()
	 * @see IStorage#getFullPath()
	 */
	public IPath getFullPath();

	/**
	 * Returns a list of past states of this file known to this workspace.
	 * Recently added states first.
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 * 
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @return an array of states of this file
	 * @exception CoreException if this method fails.
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 */
	public IFileState[] getHistory(IProgressMonitor monitor) throws CoreException;

	/**
	 * Returns the name of this file. 
	 * This refinement of the corresponding <code>IStorage</code> and <code>IResource</code>
	 * methods links the semantics of resource and storage object names such that
	 * <code>IFile</code>s always have a name and that name equivalent to the
	 * last segment of its full path.
	 *
	 * @see IResource#getName()
	 * @see IStorage#getName()
	 */
	public String getName();

	/**
	 * Returns whether this file is read-only.
	 * This refinement of the corresponding <code>IStorage</code> and <code>IResource</code>
	 * methods links the semantics of read-only resources and read-only storage objects.
	 *
	 * @see IResource#isReadOnly()
	 * @see IStorage#isReadOnly()
	 */
	public boolean isReadOnly();

	/**
	 * Moves this resource to be at the given location.
	 * <p>
	 * This is a convenience method, fully equivalent to:
	 * <pre>
	 *   move(destination, (keepHistory ? KEEP_HISTORY : IResource.NONE) | (force ? FORCE : IResource.NONE), monitor);
	 * </pre>
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that this file has been removed from its parent and a new file
	 * has been added to the parent of the destination.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 * 
	 * @param destination the destination path 
	 * @param force a flag controlling whether resources that are not
	 *    in sync with the local file system will be tolerated
	 * @param keepHistory a flag controlling whether files under this folder
	 *    should be stored in the workspace's local history
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this resource could not be moved. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> This resource is not local.</li>
	 * <li> The resource corresponding to the parent destination path does not exist.</li>
	 * <li> The resource corresponding to the parent destination path is a closed 
	 *      project.</li>
	 * <li> A resource at destination path does exist.</li>
	 * <li> A resource of a different type exists at the destination path.</li>
	 * <li> This resource is out of sync with the local file system
	 *      and <code>force</code> is <code>false</code>.</li>
	 * <li> The workspace and the local file system are out of sync
	 *      at the destination resource or one of its descendents.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 *
	 * @see IResource#move(IPath,int,IProgressMonitor)
	 * @see IResourceRuleFactory#moveRule(IResource, IResource)
	 */
	public void move(IPath destination, boolean force, boolean keepHistory, IProgressMonitor monitor) throws CoreException;

	/**
	 * Sets the charset for this file. Passing a value of <code>null</code>
	 * will remove the charset setting for this resource.
	 * 
	 * @param newCharset a charset name, or <code>null</code>
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> An error happened while persisting this setting.</li> 
	 * </ul>
	 * @see #getCharset()
	 * @since 3.0
	 * @deprecated Replaced by {@link #setCharset(String, IProgressMonitor)} which 
	 * 	is a workspace operation and reports changes in resource deltas.
	 */
	public void setCharset(String newCharset) throws CoreException;

	/**
	 * Sets the charset for this file. Passing a value of <code>null</code>
	 * will remove the charset setting for this resource.
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that this file's encoding has changed.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 * 
	 * @param newCharset a charset name, or <code>null</code>
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> An error happened while persisting this setting.</li> 
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See {@link IResourceChangeEvent} for more details.</li>
	 * </ul>
	 * @see #getCharset()
	 * @see IResourceRuleFactory#charsetRule(IResource)
	 * @since 3.0
	 */
	public void setCharset(String newCharset, IProgressMonitor monitor) throws CoreException;

	/**
	 * Sets the contents of this file to the bytes in the given input stream.
	 * <p>
	 * This is a convenience method, fully equivalent to:
	 * <pre>
	 *   setContents(source, (keepHistory ? KEEP_HISTORY : IResource.NONE) | (force ? FORCE : IResource.NONE), monitor);
	 * </pre>
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that this file's contents have been changed.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param source an input stream containing the new contents of the file
	 * @param force a flag controlling how to deal with resources that
	 *    are not in sync with the local file system
	 * @param keepHistory a flag indicating whether or not store
	 *    the current contents in the local history
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * <li> The workspace is not in sync with the corresponding location
	 *       in the local file system and <code>force </code> is <code>false</code>.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * <li> The file modification validator disallowed the change.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see #setContents(java.io.InputStream,int,IProgressMonitor)
	 */
	public void setContents(InputStream source, boolean force, boolean keepHistory, IProgressMonitor monitor) throws CoreException;

	/**
	 * Sets the contents of this file to the bytes in the given file state.
	 * <p>
	 * This is a convenience method, fully equivalent to:
	 * <pre>
	 *   setContents(source, (keepHistory ? KEEP_HISTORY : IResource.NONE) | (force ? FORCE : IResource.NONE), monitor);
	 * </pre>
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that this file's content have been changed.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param source a previous state of this resource
	 * @param force a flag controlling how to deal with resources that
	 *    are not in sync with the local file system
	 * @param keepHistory a flag indicating whether or not store
	 *    the current contents in the local history
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> The state does not exist.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * <li> The workspace is not in sync with the corresponding location
	 *       in the local file system and <code>force </code> is <code>false</code>.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * <li> The file modification validator disallowed the change.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see #setContents(IFileState,int,IProgressMonitor)
	 */
	public void setContents(IFileState source, boolean force, boolean keepHistory, IProgressMonitor monitor) throws CoreException;

	/**
	 * Sets the contents of this file to the bytes in the given input stream.
	 * The stream will get closed whether this method succeeds or fails.
	 * If the stream is <code>null</code> then the content is set to be the
	 * empty sequence of bytes.
	 * <p>
	 * The <code>FORCE</code> update flag controls how this method deals with
	 * cases where the workspace is not completely in sync with the local file 
	 * system. If <code>FORCE</code> is not specified, the method will only attempt
	 * to overwrite a corresponding file in the local file system provided
	 * it is in sync with the workspace. This option ensures there is no 
	 * unintended data loss; it is the recommended setting.
	 * However, if <code>FORCE</code> is specified, an attempt will be made
	 * to write a corresponding file in the local file system, overwriting any
	 * existing one if need be. In either case, if this method succeeds, the 
	 * resource will be marked as being local (even if it wasn't before).
	 * </p>
	 * <p>
	 * The <code>KEEP_HISTORY</code> update flag controls whether or not a copy of
	 * current contents of this file should be captured in the workspace's local
	 * history (properties are not recorded in the local history). The local history
	 * mechanism serves as a safety net to help the user recover from mistakes that
	 * might otherwise result in data loss. Specifying <code>KEEP_HISTORY</code>
	 * is recommended except in circumstances where past states of the files are of
	 * no conceivable interest to the user. Note that local history is maintained
	 * with each individual project, and gets discarded when a project is deleted
	 * from the workspace.  This flag is ignored if the file was not previously local.
	 * </p>
	 * <p>
	 * Update flags other than <code>FORCE</code> and <code>KEEP_HISTORY</code> 
	 * are ignored.
	 * </p>
	 * <p>
	 * Prior to modifying the contents of this file, the file modification validator (if provided 
	 * by the VCM plug-in), will be given a chance to perform any last minute preparations.  Validation
	 * is performed by calling <code>IFileModificationValidator.validateSave</code> on this file.
	 * If the validation fails, then this operation will fail.
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that this file's content have been changed.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param source an input stream containing the new contents of the file
	 * @param updateFlags bit-wise or of update flag constants
	 *   (<code>FORCE</code> and <code>KEEP_HISTORY</code>)
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * <li> The workspace is not in sync with the corresponding location
	 *       in the local file system and <code>FORCE</code> is not specified.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * <li> The file modification validator disallowed the change.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see IResourceRuleFactory#modifyRule(IResource)
	 * @since 2.0
	 */
	public void setContents(InputStream source, int updateFlags, IProgressMonitor monitor) throws CoreException;

	/**
	 * Sets the contents of this file to the bytes in the given file state.
	 * <p>
	 * The <code>FORCE</code> update flag controls how this method deals with
	 * cases where the workspace is not completely in sync with the local file 
	 * system. If <code>FORCE</code> is not specified, the method will only attempt
	 * to overwrite a corresponding file in the local file system provided
	 * it is in sync with the workspace. This option ensures there is no 
	 * unintended data loss; it is the recommended setting.
	 * However, if <code>FORCE</code> is specified, an attempt will be made
	 * to write a corresponding file in the local file system, overwriting any
	 * existing one if need be. In either case, if this method succeeds, the 
	 * resource will be marked as being local (even if it wasn't before).
	 * </p>
	 * <p>
	 * The <code>KEEP_HISTORY</code> update flag controls whether or not a copy of
	 * current contents of this file should be captured in the workspace's local
	 * history (properties are not recorded in the local history). The local history
	 * mechanism serves as a safety net to help the user recover from mistakes that
	 * might otherwise result in data loss. Specifying <code>KEEP_HISTORY</code>
	 * is recommended except in circumstances where past states of the files are of
	 * no conceivable interest to the user. Note that local history is maintained
	 * with each individual project, and gets discarded when a project is deleted
	 * from the workspace.  This flag is ignored if the file was not previously local.
	 * </p>
	 * <p>
	 * Update flags other than <code>FORCE</code> and <code>KEEP_HISTORY</code> 
	 * are ignored.
	 * </p>
	 * <p>
	 * Prior to modifying the contents of this file, the file modification validator (if provided 
	 * by the VCM plug-in), will be given a chance to perform any last minute preparations.  Validation
	 * is performed by calling <code>IFileModificationValidator.validateSave</code> on this file.
	 * If the validation fails, then this operation will fail.
	 * </p>
	 * <p>
	 * This method changes resources; these changes will be reported
	 * in a subsequent resource change event, including an indication 
	 * that this file's content have been changed.
	 * </p>
	 * <p>
	 * This method is long-running; progress and cancellation are provided
	 * by the given progress monitor. 
	 * </p>
	 *
	 * @param source a previous state of this resource
	 * @param updateFlags bit-wise or of update flag constants
	 *   (<code>FORCE</code> and <code>KEEP_HISTORY</code>)
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *    reporting is not desired
	 * @exception CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> This resource does not exist.</li>
	 * <li> The state does not exist.</li>
	 * <li> The corresponding location in the local file system
	 *       is occupied by a directory.</li>
	 * <li> The workspace is not in sync with the corresponding location
	 *       in the local file system and <code>FORCE</code> is not specified.</li>
	 * <li> Resource changes are disallowed during certain types of resource change 
	 *       event notification. See <code>IResourceChangeEvent</code> for more details.</li>
	 * <li> The file modification validator disallowed the change.</li>
	 * </ul>
	 * @exception OperationCanceledException if the operation is canceled. 
	 * Cancelation can occur even if no progress monitor is provided.
	 * @see IResourceRuleFactory#modifyRule(IResource)
	 * @since 2.0
	 */
	public void setContents(IFileState source, int updateFlags, IProgressMonitor monitor) throws CoreException;
}
