Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2012 IBM Corporation and others. * 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: * IBM Corporation - initial API and implementation * Sergey Prigogin (Google) *******************************************************************************/ package org.eclipse.cdt.codan.internal.ui.preferences; import org.eclipse.cdt.codan.internal.ui.CodanUIMessages; import org.eclipse.jface.preference.FieldEditor; import org.eclipse.jface.viewers.CheckStateChangedEvent; import org.eclipse.jface.viewers.CheckboxTreeViewer; import org.eclipse.jface.viewers.ICheckStateListener; import org.eclipse.jface.viewers.ITreeContentProvider; import org.eclipse.jface.viewers.StructuredViewer; import org.eclipse.jface.viewers.ViewerComparator; import org.eclipse.swt.SWT; import org.eclipse.swt.layout.GridData; import org.eclipse.swt.layout.GridLayout; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Control; import org.eclipse.swt.widgets.Shell; import org.eclipse.swt.widgets.Tree; /** * An abstract field editor that manages a checked tree. Values in the tree * should be set outside by setting getTreeViewer().setContentProvider() and * getTreeViewer().setInput() Control stores checked elements only in preference * storage. * * <p> * Subclasses may implement the <code>parseString</code>, * <code>createList</code>, <code>storeValue</code> and * <code>getListSeparator</code> framework methods. * </p> */ public abstract class CheckedTreeEditor extends FieldEditor implements ICheckStateListener { /** * The list widget; <code>null</code> if none (before creation or after disposal). */ private CheckboxTreeViewer treeViewer; private Composite listParent; private boolean isValid; private boolean emptySelectionAllowed; /** * Creates a new list field editor */ protected CheckedTreeEditor() { } /** * Creates a list field editor. * * @param name * the name of the preference this field editor works on * @param labelText * the label text of the field editor * @param parent * the parent of the field editor's control */ public CheckedTreeEditor(String name, String labelText, Composite parent) { init(name, labelText); createControl(parent); } /* * (non-Javadoc) Method declared on FieldEditor. */ @Override protected void adjustForNumColumns(int numColumns) { Control control = getLabelControl(); if (control != null) { ((GridData) control.getLayoutData()).horizontalSpan = numColumns; ((GridData) getTreeControl().getLayoutData()).horizontalSpan = numColumns; } else { ((GridData) getTreeControl().getLayoutData()).horizontalSpan = numColumns; } } /* * (non-Javadoc) Method declared on FieldEditor. */ @Override protected void doFillIntoGrid(Composite parent, int numColumns) { doFillLabelIntoGrid(parent, numColumns); doFillBoxIntoGrid(parent, numColumns); } protected void doFillLabelIntoGrid(Composite parent, int numColumns) { String text = getLabelText(); if (text != null && text.length() > 0) { Control control = getLabelControl(parent); GridData gd = new GridData(); gd.horizontalSpan = numColumns; control.setLayoutData(gd); } } protected void doFillBoxIntoGrid(Composite parent, int numColumns) { GridData gd; Control list = createListControl(parent); gd = new GridData(GridData.FILL_HORIZONTAL); gd.verticalAlignment = GridData.FILL; gd.horizontalSpan = numColumns; gd.grabExcessHorizontalSpace = true; gd.grabExcessVerticalSpace = true; list.setLayoutData(gd); } /* * (non-Javadoc) Method declared on FieldEditor. */ @Override protected void doLoad() { if (getTreeControl() != null) { String s = getPreferenceStore().getString(getPreferenceName()); getViewer().setInput(modelFromString(s)); } } protected abstract Object modelFromString(String s); Control getTreeControl() { if (treeViewer == null) return null; return treeViewer.getControl(); } public CheckboxTreeViewer getTreeViewer() { return treeViewer; } /** * @Override * @see org.eclipse.jface.viewers.ICheckStateListener#checkStateChanged(org.eclipse.jface.viewers.CheckStateChangedEvent) */ @Override public void checkStateChanged(CheckStateChangedEvent event) { Object element = event.getElement(); treeViewer.setGrayed(element, false); treeViewer.setSubtreeChecked(element, event.getChecked()); Object parent = getContentProvider().getParent(element); if (parent != null) { updateCheckedState(parent); treeViewer.setParentsGrayed(parent, true); } refreshValidState(); } private ITreeContentProvider getContentProvider() { return ((ITreeContentProvider) treeViewer.getContentProvider()); } private void updateCheckedState(Object parent) { Object[] children = getContentProvider().getChildren(parent); int i, count = 0; for (i = 0; i < children.length; i++) { Object object = children[i]; if (treeViewer.getChecked(object)) { count++; } } if (count > 0) { treeViewer.setChecked(parent, true); } if (count == 0) { treeViewer.setGrayed(parent, false); treeViewer.setChecked(parent, false); return; } if (count < i) { treeViewer.setGrayed(parent, true); } } /* * (non-Javadoc) Method declared on FieldEditor. */ @Override protected void doLoadDefault() { if (getTreeControl() != null) { String s = getPreferenceStore().getDefaultString(getPreferenceName()); getViewer().setInput(modelFromString(s)); } } /* * (non-Javadoc) Method declared on FieldEditor. */ @Override protected void doStore() { String s = modelToString(getViewer().getInput()); if (s != null) { getPreferenceStore().setValue(getPreferenceName(), s); } } /** * Returns this field editor's list control. * * @param parent * the parent control * @return the list control */ public Tree createListControl(Composite parent) { Tree table = (Tree) getTreeControl(); if (table == null) { listParent = parent; treeViewer = new CheckboxTreeViewer(parent, SWT.BORDER | SWT.MULTI | SWT.V_SCROLL | SWT.H_SCROLL | SWT.FULL_SELECTION); table = treeViewer.getTree(); table.setFont(parent.getFont()); treeViewer.setComparator(new ViewerComparator()); treeViewer.addCheckStateListener(this); } else { checkParent(table, parent); } return table; } public StructuredViewer getViewer() { return treeViewer; } /* * (non-Javadoc) Method declared on FieldEditor. */ @Override public int getNumberOfControls() { return 2; } /** * Returns this field editor's shell. * <p> * This method is internal to the framework; subclassers should not call * this method. * </p> * * @return the shell */ protected Shell getShell() { return treeViewer.getControl().getShell(); } /* * (non-Javadoc) Method declared on FieldEditor. */ @Override public void setFocus() { if (getTreeControl() != null) { getTreeControl().setFocus(); } } /* * @see FieldEditor.setEnabled(boolean,Composite). */ @Override public void setEnabled(boolean enabled, Composite parent) { super.setEnabled(enabled, parent); createListControl(parent).setEnabled(enabled); } /** * Combines the given list of items into a single string. This method is the * converse of <code>parseString</code>. * <p> * Subclasses may implement this method. * </p> * * @return the combined string * @see #modelFromString(String) */ protected abstract String modelToString(Object model); @Override protected void createControl(Composite parent) { GridLayout ly = (GridLayout) parent.getLayout(); doFillIntoGrid(parent, ly.numColumns); } /** * @param b */ public void setEnabled(boolean b) { setEnabled(b, listParent); } public Composite getTreeParent() { return listParent; } /* * (non-Javadoc) Method declared on FieldEditor. */ @Override public boolean isValid() { return isValid; } /* * (non-Javadoc) Method declared on FieldEditor. */ @Override protected void refreshValidState() { isValid = checkState(); } protected boolean checkState() { if (!emptySelectionAllowed) { Object[] checkedElements = getTreeViewer().getCheckedElements(); if (checkedElements.length == 0) { showErrorMessage(CodanUIMessages.CheckedTreeEditor_SelectionCannotBeEmpty); return false; } } clearErrorMessage(); return true; } public final boolean isEmptySelectionAllowed() { return emptySelectionAllowed; } public final void setEmptySelectionAllowed(boolean emptySelectionAllowed) { this.emptySelectionAllowed = emptySelectionAllowed; } }