org.eclipse.nebula.widgets.nattable.extension.glazedlists/src/org/eclipse/nebula/widgets/nattable/extension/glazedlists/hideshow/GlazedListsRowHideShowLayer.java

/*******************************************************************************
 * Copyright (c) 2013, 2020 Dirk Fauth and others.
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *    Dirk Fauth <dirk.fauth@googlemail.com> - initial API and implementation
 *******************************************************************************/
package org.eclipse.nebula.widgets.nattable.extension.glazedlists.hideshow;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.Properties;
import java.util.stream.Collectors;

import org.apache.commons.codec.binary.Base64;
import org.eclipse.nebula.widgets.nattable.command.ILayerCommandHandler;
import org.eclipse.nebula.widgets.nattable.data.IRowDataProvider;
import org.eclipse.nebula.widgets.nattable.data.IRowIdAccessor;
import org.eclipse.nebula.widgets.nattable.hideshow.IRowHideShowLayer;
import org.eclipse.nebula.widgets.nattable.hideshow.command.HideRowByIndexCommandHandler;
import org.eclipse.nebula.widgets.nattable.hideshow.command.MultiRowHideCommandHandler;
import org.eclipse.nebula.widgets.nattable.hideshow.command.MultiRowShowCommandHandler;
import org.eclipse.nebula.widgets.nattable.hideshow.command.RowHideCommandHandler;
import org.eclipse.nebula.widgets.nattable.hideshow.command.RowPositionHideCommandHandler;
import org.eclipse.nebula.widgets.nattable.hideshow.command.ShowAllRowsCommandHandler;
import org.eclipse.nebula.widgets.nattable.layer.AbstractLayerTransform;
import org.eclipse.nebula.widgets.nattable.layer.ILayer;
import org.eclipse.nebula.widgets.nattable.layer.IUniqueIndexLayer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import ca.odell.glazedlists.FilterList;
import ca.odell.glazedlists.matchers.AbstractMatcherEditor;
import ca.odell.glazedlists.matchers.CompositeMatcherEditor;
import ca.odell.glazedlists.matchers.Matcher;
import ca.odell.glazedlists.matchers.MatcherEditor;

/**
 * Adds the functionality for manually hiding rows in a NatTable that is based
 * on GlazedLists. Technically it will filter items by id in the
 * {@link FilterList}.
 * <p>
 * Note: If you want to add row hide/show AND filtering to your NatTable, you
 * need to use the DefaultGlazedListsStaticFilterStrategy and add the
 * {@link Matcher} that is used by this command as a static
 * {@link MatcherEditor}. Otherwise these two functions will not work correctly
 * together.
 */
public class GlazedListsRowHideShowLayer<T> extends AbstractLayerTransform implements IRowHideShowLayer, IUniqueIndexLayer {

    private static final Logger LOG = LoggerFactory.getLogger(GlazedListsRowHideShowLayer.class);

    /**
     * Key for persisting the number of hidden row id's. This is necessary
     * because the id's are serializables and reading them againd by
     * ObjectInputStream need to know how long to read.
     */
    public static final String PERSISTENCE_KEY_HIDDEN_ROW_IDS_COUNT = ".hiddenRowIDsCount"; //$NON-NLS-1$
    public static final String PERSISTENCE_KEY_HIDDEN_ROW_IDS = ".hiddenRowIDs"; //$NON-NLS-1$

    /**
     * The collection of row id's that are hidden.
     */
    private final HashSet<Serializable> rowIdsToHide = new HashSet<>();

    /**
     * The {@link IRowIdAccessor} that is used to extract the id out of the row
     * object. This is necessary to determine the row object to hide in terms of
     * content.
     */
    private final IRowIdAccessor<T> rowIdAccessor;

    /**
     * The {@link IRowDataProvider} needed to get the object at a given position
     * so it is possible to retrieve the id that is used for filtering.
     */
    private final IRowDataProvider<T> rowDataProvider;

    /**
     * The {@link MatcherEditor} that is used to filter the rows with the
     * specified id's.
     */
    private final HideRowMatcherEditor hideRowByIdMatcherEditor = new HideRowMatcherEditor();

    /**
     * Creates a {@link GlazedListsRowHideShowLayer} for adding row hide/show
     * for GlazedLists based NatTables. Using this constructor will only
     * instantiate this layer. To use this correctly you need to register the
     * local row hide {@link MatcherEditor} against the {@link FilterList}
     * yourself.
     *
     * @param underlyingLayer
     *            The underlying layer.
     * @param rowDataProvider
     *            The {@link IRowDataProvider} needed to get the object at a
     *            given position so it is possible to retrieve the id that is
     *            used for filtering.
     * @param rowIdAccessor
     *            The {@link IRowIdAccessor} that is used to extract the id out
     *            of the row object. This is necessary to determine the row
     *            object to hide in terms of content.
     */
    public GlazedListsRowHideShowLayer(ILayer underlyingLayer, IRowDataProvider<T> rowDataProvider, IRowIdAccessor<T> rowIdAccessor) {
        super(underlyingLayer);
        if (rowIdAccessor == null) {
            throw new IllegalArgumentException("rowIdAccessor can not be null!"); //$NON-NLS-1$
        }

        this.rowDataProvider = rowDataProvider;
        this.rowIdAccessor = rowIdAccessor;

        registerCommandHandlers();
    }

    /**
     * Creates a {@link GlazedListsRowHideShowLayer} for adding row hide/show
     * for GlazedLists based NatTables. Using this constructor will add the
     * {@link MatcherEditor} to the given {@link FilterList}. This might not
     * work correctly in combination with other filters like e.g. the filter
     * row.
     *
     * @param underlyingLayer
     *            The underlying layer.
     * @param rowDataProvider
     *            The {@link IRowDataProvider} needed to get the object at a
     *            given position so it is possible to retrieve the id that is
     *            used for filtering.
     * @param rowIdAccessor
     *            The {@link IRowIdAccessor} that is used to extract the id out
     *            of the row object. This is necessary to determine the row
     *            object to hide in terms of content.
     * @param filterList
     *            The {@link FilterList} to apply the local row hide
     *            {@link Matcher} to.
     */
    public GlazedListsRowHideShowLayer(
            ILayer underlyingLayer,
            IRowDataProvider<T> rowDataProvider,
            IRowIdAccessor<T> rowIdAccessor,
            FilterList<T> filterList) {
        super(underlyingLayer);
        if (rowIdAccessor == null) {
            throw new IllegalArgumentException("rowIdAccessor can not be null!"); //$NON-NLS-1$
        }
        if (filterList == null) {
            throw new IllegalArgumentException("filterList can not be null!"); //$NON-NLS-1$
        }

        this.rowDataProvider = rowDataProvider;
        this.rowIdAccessor = rowIdAccessor;

        filterList.setMatcherEditor(this.hideRowByIdMatcherEditor);

        registerCommandHandlers();
    }

    /**
     * Creates a {@link GlazedListsRowHideShowLayer} for adding row hide/show
     * for GlazedLists based NatTables. Using this constructor will add the
     * {@link MatcherEditor} to the given {@link CompositeMatcherEditor}. This
     * way it is possible to add more filter logic than only the row hide
     * filter.
     *
     * @param underlyingLayer
     *            The underlying layer.
     * @param rowDataProvider
     *            The {@link IRowDataProvider} needed to get the object at a
     *            given position so it is possible to retrieve the id that is
     *            used for filtering.
     * @param rowIdAccessor
     *            The {@link IRowIdAccessor} that is used to extract the id out
     *            of the row object. This is necessary to determine the row
     *            object to hide in terms of content.
     * @param matcherEditor
     *            The {@link CompositeMatcherEditor} to which the local row hide
     *            {@link Matcher} should be added.
     */
    public GlazedListsRowHideShowLayer(
            ILayer underlyingLayer,
            IRowDataProvider<T> rowDataProvider,
            IRowIdAccessor<T> rowIdAccessor,
            CompositeMatcherEditor<T> matcherEditor) {
        super(underlyingLayer);
        if (rowIdAccessor == null) {
            throw new IllegalArgumentException("rowIdAccessor can not be null!"); //$NON-NLS-1$
        }
        if (matcherEditor == null) {
            throw new IllegalArgumentException("matcherEditor can not be null!"); //$NON-NLS-1$
        }

        this.rowDataProvider = rowDataProvider;
        this.rowIdAccessor = rowIdAccessor;

        matcherEditor.getMatcherEditors().add(this.hideRowByIdMatcherEditor);

        registerCommandHandlers();
    }

    /**
     * Register the {@link ILayerCommandHandler} that will handle the row
     * hide/show events for this layer.
     */
    @Override
    protected void registerCommandHandlers() {
        registerCommandHandler(new RowHideCommandHandler(this));
        registerCommandHandler(new MultiRowHideCommandHandler(this));
        registerCommandHandler(new ShowAllRowsCommandHandler(this));
        registerCommandHandler(new MultiRowShowCommandHandler(this));
        registerCommandHandler(new RowPositionHideCommandHandler(this));
        registerCommandHandler(new HideRowByIndexCommandHandler(this));
    }

    /**
     *
     * @return The {@link MatcherEditor} that is used to filter rows via row
     *         id's.
     *
     * @since 2.0
     */
    public MatcherEditor<T> getHideRowMatcherEditor() {
        return this.hideRowByIdMatcherEditor;
    }

    @Override
    public void hideRowPositions(int... rowPositions) {
        hideRows(Arrays.stream(rowPositions)
                .map(this::getRowIndexByPosition)
                .mapToObj(rowIndex -> this.rowIdAccessor.getRowId(this.rowDataProvider.getRowObject(rowIndex)))
                .collect(Collectors.toSet()));
    }

    /**
     * Hide the rows at the given positions. Will collect the id's of the rows
     * at the given positions as this layer operates on content rather than
     * positions.
     *
     * @param rowPositions
     *            The positions of the rows to hide.
     */
    @Override
    public void hideRowPositions(Collection<Integer> rowPositions) {
        hideRowPositions(rowPositions.stream().mapToInt(Integer::intValue).toArray());
    }

    @Override
    public void hideRowIndexes(int... rowIndexes) {
        hideRows(Arrays.stream(rowIndexes)
                .mapToObj(rowIndex -> this.rowIdAccessor.getRowId(this.rowDataProvider.getRowObject(rowIndex)))
                .collect(Collectors.toSet()));
    }

    /**
     * Hide the rows at the given indexes. Will collect the id's of the rows at
     * the given positions as this layer operates on content rather than
     * positions.
     *
     * @param rowIndexes
     *            The indexes of the rows to hide.
     */
    @Override
    public void hideRowIndexes(Collection<Integer> rowIndexes) {
        hideRowPositions(rowIndexes.stream().mapToInt(Integer::intValue).toArray());
    }

    @Override
    public void showRowIndexes(int... rowIndexes) {
        showRows(Arrays.stream(rowIndexes)
                .mapToObj(rowIndex -> this.rowIdAccessor.getRowId(this.rowDataProvider.getRowObject(rowIndex)))
                .collect(Collectors.toSet()));
    }

    /**
     * Show the rows with the given indexes again. Will collect the id's of the
     * rows at the given positions as this layer operates on content rather than
     * positions.
     *
     * @param rowIndexes
     *            The indexes of the rows that should be showed again.
     */
    @Override
    public void showRowIndexes(Collection<Integer> rowIndexes) {
        showRowIndexes(rowIndexes.stream().mapToInt(Integer::intValue).toArray());
    }

    /**
     * Hide the rows that contain the objects with the given row ids.
     *
     * @param rowIds
     *            The row ids of the rows that should be hidden.
     */
    public void hideRows(Collection<Serializable> rowIds) {
        this.rowIdsToHide.addAll(rowIds);
        this.hideRowByIdMatcherEditor.fireChange();
    }

    /**
     * Show the rows that contain the objects with the given row ids. Will of
     * course only have impact if those rows are currently hidden.
     *
     * @param rowIds
     *            The row ids of the rows that should be showed.
     */
    public void showRows(Collection<Serializable> rowIds) {
        this.rowIdsToHide.removeAll(rowIds);
        this.hideRowByIdMatcherEditor.fireChange();
    }

    /**
     * {@inheritDoc}
     * <p>
     * <b>This method is not supported by this layer as hidden rows are actually
     * filtered from the content and therefore not next to another position on a
     * deeper layer!</b>
     * </p>
     */
    @Override
    public void showRowPosition(int rowPosition, boolean showToTop, boolean showAll) {
        throw new UnsupportedOperationException(
                "Hidden rows are filtered from the content and therefore not next to any other row position"); //$NON-NLS-1$
    }

    /**
     * Show all rows that where previously hidden.
     */
    @Override
    public void showAllRows() {
        this.rowIdsToHide.clear();
        this.hideRowByIdMatcherEditor.fireChange();
    }

    /**
     * @return The {@link MatcherEditor} that is used to filter the rows with
     *         the specified id's.
     */
    public MatcherEditor<T> getMatcherEditor() {
        return this.hideRowByIdMatcherEditor;
    }

    @Override
    public int getColumnPositionByIndex(int columnIndex) {
        return ((IUniqueIndexLayer) getUnderlyingLayer()).getColumnPositionByIndex(columnIndex);
    }

    @Override
    public int getRowPositionByIndex(int rowIndex) {
        return ((IUniqueIndexLayer) getUnderlyingLayer()).getRowPositionByIndex(rowIndex);
    }

    @Override
    public void saveState(String prefix, Properties properties) {
        if (!this.rowIdsToHide.isEmpty()) {
            // store the number of row id's that will be hidden
            properties.setProperty(prefix
                    + PERSISTENCE_KEY_HIDDEN_ROW_IDS_COUNT,
                    Integer.toString(this.rowIdsToHide.size()));

            try (ByteArrayOutputStream bos = new ByteArrayOutputStream();
                    ObjectOutputStream out = new ObjectOutputStream(bos)) {
                for (Serializable serializable : this.rowIdsToHide) {
                    out.writeObject(serializable);
                }
                properties.setProperty(prefix + PERSISTENCE_KEY_HIDDEN_ROW_IDS,
                        new String(Base64.encodeBase64(bos.toByteArray())));
            } catch (Exception e) {
                LOG.error("Error while persisting GlazedListsRowHideShowLayer state", e); //$NON-NLS-1$
            }
        }

        super.saveState(prefix, properties);
    }

    @Override
    public void loadState(String prefix, Properties properties) {
        this.rowIdsToHide.clear();
        String property = properties.getProperty(prefix + PERSISTENCE_KEY_HIDDEN_ROW_IDS_COUNT);
        int count = property != null ? Integer.valueOf(property) : 0;
        property = properties.getProperty(prefix + PERSISTENCE_KEY_HIDDEN_ROW_IDS);
        if (property != null) {
            try (ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(Base64.decodeBase64(property.getBytes())))) {
                Serializable ser = null;
                for (int i = 0; i < count; i++) {
                    ser = (Serializable) in.readObject();
                    this.rowIdsToHide.add(ser);
                }
            } catch (Exception e) {
                LOG.error("Error while restoring GlazedListsRowHideShowLayer state", e); //$NON-NLS-1$
            }
        }
        this.hideRowByIdMatcherEditor.fireChange();

        super.loadState(prefix, properties);
    }

    /**
     * {@link MatcherEditor} implementation that will only match objects that
     * are not hidden by id. It also enables to fire change events to indicate
     * changes to the filter.
     */
    class HideRowMatcherEditor extends AbstractMatcherEditor<T> {
        /**
         * The {@link Matcher} that is used to filter the rows with the
         * specified id's.
         */
        private final Matcher<T> hideRowByIdMatcher = rowObject -> !GlazedListsRowHideShowLayer.this.rowIdsToHide.contains(GlazedListsRowHideShowLayer.this.rowIdAccessor.getRowId(rowObject));

        /**
         * Fire a change so the listeners can be informed about a change for the
         * {@link Matcher}
         */
        public void fireChange() {
            fireChanged(this.hideRowByIdMatcher);
        }
    }

}