DocumentPartitioner.java

/*******************************************************************************
 * Copyright (c) 2012-2015 Codenvy, S.A.
 * 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:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.ide.ext.java.jdt.text;

import org.eclipse.che.ide.api.editor.text.TypedRegion;

/**
 * A document partitioner divides a document into a set of disjoint text partitions. Each partition has a content type, an offset,
 * and a length. The document partitioner is connected to one document and informed about all changes of this document before any
 * of the document's document listeners. A document partitioner can thus incrementally update on the receipt of a document change
 * event.
 * <p>
 * <p/>
 * In order to provided backward compatibility for clients of <code>DocumentPartitioner</code>, extension interfaces are used to
 * provide a means of evolution.
 * <p>
 * Clients may implement this interface and its extension interfaces or use the standard implementation
 * <code>DefaultPartitioner</code>.
 * </p>
 *
 * @see Document
 */
public interface DocumentPartitioner {

    /**
     * Connects the partitioner to a document. Connect indicates the begin of the usage of the receiver as partitioner of the given
     * document. Thus, resources the partitioner needs to be operational for this document should be allocated.
     * <p/>
     * <p/>
     * The caller of this method must ensure that this partitioner is also set as the document's document partitioner.
     *
     * @param document
     *         the document to be connected to
     */
    void connect(Document document);

    /**
     * Disconnects the partitioner from the document it is connected to. Disconnect indicates the end of the usage of the receiver
     * as partitioner of the connected document. Thus, resources the partitioner needed to be operation for its connected document
     * should be deallocated.
     * <p/>
     * The caller of this method should also must ensure that this partitioner is no longer the document's partitioner.
     */
    void disconnect();

    /**
     * Informs about a forthcoming document change. Will be called by the connected document and is not intended to be used by
     * clients other than the connected document.
     *
     * @param event
     *         the event describing the forthcoming change
     */
    void documentAboutToBeChanged(DocumentEvent event);

    /**
     * The document has been changed. The partitioner updates the document's partitioning and returns whether the structure of the
     * document partitioning has been changed, i.e. whether partitions have been added or removed. Will be called by the connected
     * document and is not intended to be used by clients other than the connected document.
     *
     * @param event
     *         the event describing the document change
     * @return <code>true</code> if partitioning changed
     */
    boolean documentChanged(DocumentEvent event);

    /**
     * Returns the set of all legal content types of this partitioner. I.e. any result delivered by this partitioner may not
     * contain a content type which would not be included in this method's result.
     *
     * @return the set of legal content types
     */
    String[] getLegalContentTypes();

    /**
     * Returns the content type of the partition containing the given offset in the connected document. There must be a document
     * connected to this partitioner.
     *
     * @param offset
     *         the offset in the connected document
     * @return the content type of the offset's partition
     */
    String getContentType(int offset);

    /**
     * Returns the partitioning of the given range of the connected document. There must be a document connected to this
     * partitioner.
     *
     * @param offset
     *         the offset of the range of interest
     * @param length
     *         the length of the range of interest
     * @return the partitioning of the range
     */
    TypedRegion[] computePartitioning(int offset, int length);

    /**
     * Returns the partition containing the given offset of the connected document. There must be a document connected to this
     * partitioner.
     *
     * @param offset
     *         the offset for which to determine the partition
     * @return the partition containing the offset
     */
    TypedRegion getPartition(int offset);
}