Java tutorial
/******************************************************************************* * Copyright (c) 2006, 2019 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 * Tom Schindl <tom.schindl@bestsolution.at> - initial API and implementation * - fix in bug: 166346,167325,174355,195908,198035,215069,227421 *******************************************************************************/ package org.eclipse.jface.viewers; import java.util.Objects; import org.eclipse.jface.util.Policy; import org.eclipse.swt.custom.StyleRange; import org.eclipse.swt.graphics.Color; import org.eclipse.swt.graphics.Font; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.graphics.Rectangle; import org.eclipse.swt.widgets.Control; import org.eclipse.swt.widgets.Widget; /** * ViewerRow is the abstract superclass of the part that represents items in a * Table or Tree. Implementors of {@link ColumnViewer} have to provide a * concrete implementation for the underlying widget * * @since 3.3 * */ public abstract class ViewerRow implements Cloneable { /** * Constant denoting the row above the current one (value is 1). * * @see #getNeighbor(int, boolean) */ public static final int ABOVE = 1; /** * Constant denoting the row below the current one (value is 2). * * @see #getNeighbor(int, boolean) */ public static final int BELOW = 2; private static final String KEY_TEXT_LAYOUT = Policy.JFACE + "styled_label_key_"; //$NON-NLS-1$ private static final String KEY_TEXT_LAYOUT_0 = Policy.JFACE + "styled_label_key_0"; //$NON-NLS-1$ private static String[] cachedDataKeys; /** * Get the bounds of the entry at the columnIndex, * * @param columnIndex column index of interest * @return {@link Rectangle} */ public abstract Rectangle getBounds(int columnIndex); /** * Return the bounds for the whole item. * * @return {@link Rectangle} */ public abstract Rectangle getBounds(); /** * Return the item for the receiver. * * @return {@link Widget} */ public abstract Widget getItem(); /** * Return the number of columns for the receiver. * * @return the number of columns */ public abstract int getColumnCount(); /** * Return the image at the columnIndex. * * @param columnIndex column index of interest * @return {@link Image} or <code>null</code> */ public abstract Image getImage(int columnIndex); /** * Set the image at the columnIndex * * @param columnIndex column index to set image for * @param image image to set */ public abstract void setImage(int columnIndex, Image image); /** * Get the text at the columnIndex. * * @param columnIndex column index of interest * @return {@link String} */ public abstract String getText(int columnIndex); /** * Set the text at the columnIndex * * @param columnIndex column index to set text for * @param text text to set */ public abstract void setText(int columnIndex, String text); /** * Get the background at the columnIndex, * * @param columnIndex column index of interest * @return {@link Color} or <code>null</code> */ public abstract Color getBackground(int columnIndex); /** * Set the background at the columnIndex. * * @param columnIndex column index to set color for * @param color color to set */ public abstract void setBackground(int columnIndex, Color color); /** * Get the foreground at the columnIndex. * * @param columnIndex column index of interest * @return {@link Color} or <code>null</code> */ public abstract Color getForeground(int columnIndex); /** * Set the foreground at the columnIndex. * * @param columnIndex column index to set color for * @param color color to set */ public abstract void setForeground(int columnIndex, Color color); /** * Get the font at the columnIndex. * * @param columnIndex column index of interest * @return {@link Font} or <code>null</code> */ public abstract Font getFont(int columnIndex); /** * Set the {@link Font} at the columnIndex. * * @param columnIndex column index to set font for * @param font font to set */ public abstract void setFont(int columnIndex, Font font); /** * Get the ViewerCell at point. * * @param point position to get cell for * @return {@link ViewerCell} or <code>null</code> if the point is not in the * bounds of a cell */ public ViewerCell getCell(Point point) { int index = getColumnIndex(point); return getCell(index); } /** * Get the columnIndex of the point. * * @param point position to get column index for * @return int or -1 if it cannot be found. */ public int getColumnIndex(Point point) { int count = getColumnCount(); // If there are no columns the column-index is 0 if (count == 0) { return 0; } for (int i = 0; i < count; i++) { if (getBounds(i).contains(point)) { return i; } } return -1; } /** * Get a ViewerCell for the column at index. * * @param column column index of interest * @return {@link ViewerCell} or <code>null</code> if the index is negative. */ public ViewerCell getCell(int column) { if (column >= 0) return new ViewerCell((ViewerRow) clone(), column, getElement()); return null; } /** * Get the Control for the receiver. * * @return {@link Control} */ public abstract Control getControl(); /** * Returns a neighboring row, or <code>null</code> if no neighbor exists in * the given direction. If <code>sameLevel</code> is <code>true</code>, only * sibling rows (under the same parent) will be considered. * * @param direction * the direction {@link #BELOW} or {@link #ABOVE} * * @param sameLevel * if <code>true</code>, search only within sibling rows * @return the row above/below, or <code>null</code> if not found */ public abstract ViewerRow getNeighbor(int direction, boolean sameLevel); /** * The tree path used to identify an element by the unique path * * @return the path */ public abstract TreePath getTreePath(); @Override public abstract Object clone(); /** * @return the model element */ public abstract Object getElement(); @Override public int hashCode() { return Objects.hashCode(getItem()); } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; final ViewerRow other = (ViewerRow) obj; return Objects.equals(getItem(), other.getItem()); } /** * The cell at the current index (as shown in the UI). This can be different * to the original index when columns are reordered. * * @param visualIndex * the current index (as shown in the UI) * @return the cell at the currently visible index */ ViewerCell getCellAtVisualIndex(int visualIndex) { return getCell(getCreationIndex(visualIndex)); } /** * Translate the original column index to the actual one. * <p> * <b>Because of backwards API compatibility the default implementation * returns the original index. Implementators of {@link ColumnViewer} should * overwrite this method if their widget supports reordered columns</b> * </p> * * @param creationIndex * the original index * @return the current index (as shown in the UI) * @since 3.4 */ protected int getVisualIndex(int creationIndex) { return creationIndex; } /** * Translate the current column index (as shown in the UI) to the original * one. * <p> * <b>Because of backwards API compatibility the default implementation * returns the original index. Implementators of {@link ColumnViewer} should * overwrite this method if their widget supports reordered columns</b> * </p> * * @param visualIndex * the current index (as shown in the UI) * @return the original index * @since 3.4 */ protected int getCreationIndex(int visualIndex) { return visualIndex; } /** * The location and bounds of the area where the text is drawn depends on * various things (image displayed, control with SWT.CHECK) * * @param index * the column index * @return the bounds of the of the text area. May return <code>null</code> * if the underlying widget implementation doesn't provide this * information * @since 3.4 */ public Rectangle getTextBounds(int index) { return null; } /** * Returns the location and bounds of the area where the image is drawn. * * @param index * the column index * @return the bounds of the of the image area. May return <code>null</code> * if the underlying widget implementation doesn't provide this * information * @since 3.4 */ public Rectangle getImageBounds(int index) { return null; } /** * Set the style ranges to be applied on the text label at the column index * Note: Requires {@link StyledCellLabelProvider} with owner draw enabled. * * @param columnIndex * the index of the column * @param styleRanges * the styled ranges * * @since 3.4 */ public void setStyleRanges(int columnIndex, StyleRange[] styleRanges) { getItem().setData(getStyleRangesDataKey(columnIndex), styleRanges); } private String getStyleRangesDataKey(int columnIndex) { if (columnIndex == 0) return KEY_TEXT_LAYOUT_0; if (cachedDataKeys == null) { int size = Math.max(10, columnIndex + 1); cachedDataKeys = new String[size]; for (int i = 1; i < cachedDataKeys.length; i++) { cachedDataKeys[i] = KEY_TEXT_LAYOUT + i; } } else if (columnIndex >= cachedDataKeys.length) { String[] newCachedDataKeys = new String[columnIndex + 1]; System.arraycopy(cachedDataKeys, 0, newCachedDataKeys, 0, cachedDataKeys.length); for (int i = cachedDataKeys.length; i < newCachedDataKeys.length; i++) { newCachedDataKeys[i] = KEY_TEXT_LAYOUT + i; } cachedDataKeys = newCachedDataKeys; } return cachedDataKeys[columnIndex]; } /** * Returns the style ranges to be applied on the text label at the column * index or <code>null</code> if no style ranges have been set. * * @param columnIndex * the index of the column * @return styleRanges the styled ranges * * @since 3.4 */ public StyleRange[] getStyleRanges(int columnIndex) { return (StyleRange[]) getItem().getData(getStyleRangesDataKey(columnIndex)); } int getWidth(int columnIndex) { return getBounds(columnIndex).width; } /** * Scrolls the cell at this index into view * <p> * <b>Because of backwards API compatibility the default implementation is a * no-op. Implementators of {@link ColumnViewer} should overwrite this * method if their widget supports reordered columns</b> * </p> * * @param columnIndex * the column index * @return return <code>true</code> when the cell is scrolled into view * @since 3.5 */ protected boolean scrollCellIntoView(int columnIndex) { return false; } /** * Returns <code>true</code> if the column with the given index is visible * * @param columnIndex * the column index * * @return <code>true</code> if the column is visible * @since 3.5 */ protected boolean isColumnVisible(int columnIndex) { return getWidth(columnIndex) > 0; } }