| /******************************************************************************* |
| * Copyright (c) 2004, 2005 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.IOException; |
| import java.io.InputStream; |
| import org.eclipse.core.runtime.QualifiedName; |
| |
| /** |
| * Content describers know how to retrieve metadata from |
| * contents. |
| * <p> |
| * Note: It is expected that content describer implementations be declared in a package |
| * that is exempt from plug-in activation (using the Eclipse-AutoStart bundle |
| * manifest header). Since all describers are instantiated when the content type |
| * framework is initialized, failure in complying with this requirement causes |
| * premature activation, which must be avoided. Future implementations of the |
| * framework might refuse to instantiate describers if doing so would trigger |
| * activation of the corresponding plug-in. |
| * </p> |
| * <p> |
| * Describers for text-based content types should implement |
| * <code>ITextContentDescriber</code> instead. |
| * </p> |
| * <p> |
| * Clients may implement this interface. |
| * </p> |
| |
| * @see IContentDescription |
| * @since 3.0 |
| */ |
| public interface IContentDescriber { |
| /** |
| * Description result constant, indicating that it was not possible |
| * to determine whether the contents were valid for |
| * the intended content type. |
| * |
| * @see #describe |
| */ |
| int INDETERMINATE = 1; |
| /** |
| * Description result constant, indicating the contents are invalid for |
| * the intended content type. |
| * |
| * @see #describe |
| */ |
| int INVALID = 0; |
| /** |
| * Description result constant, indicating the contents are valid for |
| * the intended content type. |
| * |
| * @see #describe |
| */ |
| int VALID = 2; |
| |
| /** |
| * Tries to fill a description for the given contents. Returns |
| * an <code>int</code> indicating whether the given stream of |
| * bytes represents a valid sample for its corresponding content type. |
| * If no content description is provided, this method should perform |
| * content type validation. |
| * <p> |
| * The input stream must be kept open, and any IOExceptions while |
| * reading the stream should flow to the caller. |
| * </p> |
| * |
| * @param contents the contents to be examined |
| * @param description a description to be filled in, or <code>null</code> if |
| * only content type validation is to be performed |
| * @return one of the following:<ul> |
| * <li><code>VALID</code></li>, |
| * <li><code>INVALID</code></li>, |
| * <li><code>INDETERMINATE</code></li> |
| * </ul> |
| * @throws IOException if an I/O error occurs |
| * @see IContentDescription |
| * @see #VALID |
| * @see #INVALID |
| * @see #INDETERMINATE |
| */ |
| int describe(InputStream contents, IContentDescription description) throws IOException; |
| |
| /** |
| * Returns the properties supported by this describer. |
| * |
| * @return the supported properties |
| * @see #describe |
| */ |
| QualifiedName[] getSupportedOptions(); |
| } |