bundles/org.eclipse.core.contenttype/src/org/eclipse/core/runtime/content/IContentType.java

/*******************************************************************************
 * Copyright (c) 2004, 2009 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.runtime.content;

import java.io.*;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.QualifiedName;
import org.eclipse.core.runtime.preferences.IScopeContext;

/**
 * Content types represent and provide information on file types, such as
 * associated file names/extensions, default charset, etc.
 *
 * @noimplement This interface is not intended to be implemented by clients.
 * @since 3.0
 */
public interface IContentType extends IContentTypeSettings {
	/**
	 * File spec type flag constant, indicating that predefined file
	 * specifications should not be taken into account.
	 */
	int IGNORE_PRE_DEFINED = 0b1;
	/**
	 * File spec type flag constant, indicating that user-defined file
	 * specifications should not be taken into account.
	 */
	int IGNORE_USER_DEFINED = 0b10;
	/**
	 * File spec type constant, indicating a file name specification.
	 */
	int FILE_NAME_SPEC = 0b100;
	/**
	 * File spec type constant, indicating a file extension specification.
	 */
	int FILE_EXTENSION_SPEC = 0b1000;
	/**
	 * File spec type constant, indicating a file name pattern specification.
	 * <code>?</code> represents any single character, <code>*<code> represent any
	 * string.
	 *
	 * @since 3.7
	 */
	int FILE_PATTERN_SPEC = 0b10000;

	/**
	 * Returns a reference to this content type's base type. If this content type
	 * does not have a base type (it is a root type), returns <code>null</code>.
	 *
	 * @return this content type's base type, or <code>null</code>
	 */
	IContentType getBaseType();

	/**
	 * Returns the default content description for this content type. A default
	 * content description is returned by the content type API whenever
	 * content analysis could not find any particular information to be described
	 * about the contents being processed, so all default attributes for the
	 * content type in question apply.
	 * <p>
	 * Clients doing caching of content descriptions may choose to treat default
	 * descriptions in a special manner, since they are easily recoverable
	 * through this API.
	 * </p>
	 *
	 *  @return a content description
	 *  @since 3.1
	 */
	IContentDescription getDefaultDescription();

	/**
	 * Tries to obtain a description for the given contents.
	 * <p>
	 * Any IOExceptions that may occur while reading the given input stream
	 * will flow to the caller.  The input stream will not be closed by this
	 * operation.
	 * </p>
	 *
	 * @param contents the contents to be interpreted
	 * @param options an array of keys for all properties that should be described
	 * @return a content description if one could be obtained, or
	 * <code>null</code>
	 * @throws IOException if an error occurs while reading the contents
	 * @see IContentDescription
	 */
	IContentDescription getDescriptionFor(InputStream contents, QualifiedName[] options) throws IOException;

	/**
	 * Tries to obtain a description for the given contents.
	 * <p>
	 * Any IOExceptions that may occur while reading the given reader
	 * will flow to the caller.  The reader will not be closed by this
	 * operation.
	 * </p>
	 *
	 * @param contents the contents to be interpreted
	 * @param options an array of keys for all properties that should be described
	 * @return a content description if one could be obtained, or
	 * <code>null</code>
	 * @throws UnsupportedOperationException if this content type
	 * has a describer that does not implement
	 * <code>ITextContentDescriber</code>
	 * @throws IOException if an error occurs while reading the contents
	 * @see IContentDescription
	 */
	IContentDescription getDescriptionFor(Reader contents, QualifiedName[] options) throws IOException;

	/**
	 * Returns the default charset for this content type if one has been defined,
	 * <code>null</code> otherwise.
	 * This refinement of the corresponding <code>IContentTypeSettings</code>
	 * method also takes into account the charset defined by the content type
	 * provider (or its base content type).
	 *
	 * @return the default charset, or <code>null</code>
	 */
	@Override String getDefaultCharset();

	/**
	 * Returns file specifications from this content type. The type mask
	 * is a bit-wise or of file specification type constants indicating the
	 * file specification types of interest.
	 * This refinement of the corresponding <code>IContentTypeSettings</code>
	 * method supports additional flags because it also takes into account the
	 * file specifications defined by the content type provider (or its base
	 * content type).
	 *
	 * @param type a bit-wise or of file specification type constants. Valid
	 * flags are:
	 *<ul>
	 *<li>one of <code>FILE_EXTENSION_SPEC</code> or
	 *<code>FILE_NAME_SPEC</code></li>
	 *<li>and optionally, one of <code>IGNORE_PRE_DEFINED</code>
	 *or <code>IGNORE_USER_DEFINED</code></li>
	 *</ul>
	 * @return the file specification
	 * @see #FILE_NAME_SPEC
	 * @see #FILE_EXTENSION_SPEC
	 * @see #IGNORE_PRE_DEFINED
	 * @see #IGNORE_USER_DEFINED
	 */
	@Override String[] getFileSpecs(int type);

	/**
	 * Returns this content type's unique identifier. Each content type has an
	 * identifier by which they can be retrieved from the content type catalog.
	 *
	 * @return this content type's unique identifier
	 */
	@Override String getId();

	/**
	 * Returns a user-friendly name for this content type.
	 *
	 * @return this content type's name
	 */
	String getName();

	/**
	 * Returns whether this content type is associated with the
	 * given file name.
	 *
	 * @param fileName the file name
	 * @return <code>true</code> if this content type is associated with
	 * the given file name, <code>false</code> otherwise
	 * @see #isAssociatedWith(String, IScopeContext)
	 */
	boolean isAssociatedWith(String fileName);

	/**
	 * Returns whether this content type is associated with the
	 * given file name in the given preference scope.
	 *
	 * @param fileName the file name
	 * @param context a preference scope context
	 * @return <code>true</code> if this content type is associated with
	 * the given file name, <code>false</code> otherwise
	 * @since 3.1
	 */
	boolean isAssociatedWith(String fileName, IScopeContext context);

	/**
	 * Returns whether this content type is a kind of the given content
	 * type. A content type A is a kind of a content type B if:
	 * <ol>
	 * <li>A and B are the same content type, or</li>
	 * <li>A's base type is B, or</li>
	 * <li>A's base type is a kind of B.</li>
	 * </ol>
	 *
	 * @param another a content type
	 * @return <code>true</code> if this content type is a kind of the
	 * given content type, <code>false</code> otherwise
	 */
	boolean isKindOf(IContentType another);

	/**
	 * Returns the settings for this content type in the given
	 * preference context.
	 *
	 * @param context a preference scope context
	 * @return setting in the given context
	 * @throws CoreException if this method fails. Reasons include:
	 * <ul>
	 * <li> An error occurred obtaining the settings.</li>
	 * </ul>
	 * @since 3.1
	 */
	IContentTypeSettings getSettings(IScopeContext context) throws CoreException;
}