Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2015 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 *******************************************************************************/ package org.eclipse.ui.views.properties; import org.eclipse.core.runtime.Assert; import org.eclipse.jface.viewers.CellEditor; import org.eclipse.jface.viewers.ICellEditorValidator; import org.eclipse.jface.viewers.ILabelProvider; import org.eclipse.jface.viewers.LabelProvider; import org.eclipse.swt.widgets.Composite; /** * Standard implementation for property descriptors. * <p> * The required attributes of property descriptors (id and display name) are * passed to the constructor; the optional attributes can be configured using * the various set methods (all have reasonable default values): * <ul> * <li><code>setDescription</code></li> * <li><code>setCategory</code></li> * <li><code>setLabelProvider</code></li> * <li><code>setHelpContexts</code></li> * </ul> * Subclasses should reimplement <code>getPropertyEditor</code> to provide a * cell editor for changing the value; otherwise the property will be * effectively read only. * </p> * <p> * There are several concrete subclasses provided in this package that cover * the most common cases: * <ul> * <li><code>TextPropertyDescriptor</code> - edits with a * <code>TextCellEditor</code></li> * <li><code>ComboBoxPropertyDescriptor - edits with a * <code>ComboBoxCellEditor</code></code></li> * <li><code>ColorPropertyDescriptor - edits with a * <code>ColorCellEditor</code></code></li> * </ul> * </p> */ public class PropertyDescriptor implements IPropertyDescriptor { /** * The property id. */ private Object id; /** * The name to display for the property. */ private String display; /** * Category name, or <code>null</code> if none (the default). */ private String category = null; /** * Description of the property, or <code>null</code> if none (the default). */ private String description = null; /** * The help context ids, or <code>null</code> if none (the default). */ private Object helpIds; /** * The flags used to filter the property. */ private String[] filterFlags; /** * The object that provides the property value's text and image, or * <code>null</code> if the default label provider is used (the default). */ private ILabelProvider labelProvider = null; /** * The object to validate the values in the cell editor, or <code>null</code> * if none (the default). */ private ICellEditorValidator validator; /** * Indicates if the descriptor is compatible with other descriptors of this * type. <code>false</code> by default. */ private boolean incompatible = false; /** * Creates a new property descriptor with the given id and display name * @param id * @param displayName */ public PropertyDescriptor(Object id, String displayName) { Assert.isNotNull(id); Assert.isNotNull(displayName); this.id = id; this.display = displayName; } /** * The <code>PropertyDescriptor</code> implementation of this * <code>IPropertyDescriptor</code> method returns <code>null</code>. * <p> * Since no cell editor is returned, the property is read only. * </p> */ @Override public CellEditor createPropertyEditor(Composite parent) { return null; } /** * Returns <code>true</code> if this property descriptor is to be always * considered incompatible with any other property descriptor. * This prevents a property from displaying during multiple * selection. * * @return <code>true</code> to indicate always incompatible */ protected boolean getAlwaysIncompatible() { return incompatible; } /** * The <code>PropertyDescriptor</code> implementation of this * <code>IPropertyDescriptor</code> method returns the value set by * the <code>setCategory</code> method. If unset, this method returns * <code>null</code> indicating the default category. * * @see #setCategory */ @Override public String getCategory() { return category; } /** * The <code>PropertyDescriptor</code> implementation of this * <code>IPropertyDescriptor</code> method returns the value set by * the <code>setDescription</code> method. If unset, this method returns * <code>null</code> indicating no description. * * @see #setDescription */ @Override public String getDescription() { return description; } /** * The <code>SimplePropertyDescriptor</code> implementation of this * <code>IPropertyDescriptor</code> method returns the value supplied * on the constructor. */ @Override public String getDisplayName() { return display; } /** * The <code>SimplePropertyDescriptor</code> implementation of this * <code>IPropertyDescriptor</code> method returns the value set by * the <code>setFilterFlags</code> method. If unset, this method returns * <code>null</code>. * <p> * Valid values for these flags are declared as constants on * <code>IPropertySheetEntry</code> */ @Override public String[] getFilterFlags() { return filterFlags; } /** * The <code>SimplePropertyDescriptor</code> implementation of this * <code>IPropertyDescriptor</code> method returns the value set by * the <code>setHelpContextId</code> method. If unset, this method returns * <code>null</code>. * * @see #setHelpContextIds */ @Override public Object getHelpContextIds() { return helpIds; } /** * The <code>PropertyDescriptor</code> implementation of this * <code>IPropertyDescriptor</code> method returns the value supplied * on the constructor. */ @Override public Object getId() { return id; } /** * The <code>PropertyDescriptor</code> implementation of this * <code>IPropertyDescriptor</code> method returns the value set by * the <code>setProvider</code> method or, if no value has been set * it returns a <code>LabelProvider</code> * * @see #setLabelProvider */ @Override public ILabelProvider getLabelProvider() { if (labelProvider != null) { return labelProvider; } return new LabelProvider(); } /** * Returns the input validator for editing the property. * * @return the validator used to verify correct values for this property, * or <code>null</code> */ protected ICellEditorValidator getValidator() { return validator; } /** * Returns whether a label provider has been set on the receiver. * @return whether a label provider has been set on the receiver. * @see #setLabelProvider * @since 3.0 */ public boolean isLabelProviderSet() { return labelProvider != null; } /** * The <code>SimplePropertyDescriptor</code> implementation of this * <code>IPropertyDescriptor</code> method returns true if the other * property has the same id and category and <code>getAlwaysIncompatible()</code> * returns false */ @Override public boolean isCompatibleWith(IPropertyDescriptor anotherProperty) { if (getAlwaysIncompatible()) { return false; } // Compare id Object id1 = getId(); Object id2 = anotherProperty.getId(); if (!id1.equals(id2)) { return false; } // Compare Category (may be null) if (getCategory() == null) { if (anotherProperty.getCategory() != null) { return false; } } else { if (!getCategory().equals(anotherProperty.getCategory())) { return false; } } return true; } /** * Sets a flag indicating whether this property descriptor is to be always * considered incompatible with any other property descriptor. * Setting this flag prevents a property from displaying during multiple * selection. * * @param flag <code>true</code> to indicate always incompatible */ public void setAlwaysIncompatible(boolean flag) { incompatible = flag; } /** * Sets the category for this property descriptor. * * @param category the category for the descriptor, or <code>null</code> if none * @see #getCategory */ public void setCategory(String category) { this.category = category; } /** * Sets the description for this property descriptor. * The description should be limited to a single line so that it can be * displayed in the status line. * * @param description the description, or <code>null</code> if none * @see #getDescription */ public void setDescription(String description) { this.description = description; } /** * Sets the the filter flags for this property descriptor. * The description should be limited to a single line so that it can be * displayed in the status line. * <p> * Valid values for these flags are declared as constants on * <code>IPropertySheetEntry</code> * </p> * * @param value the filter flags * @see #getFilterFlags */ public void setFilterFlags(String value[]) { filterFlags = value; } /** * Sets the help context id for this property descriptor. * * NOTE: Help support system API's changed since 2.0 and arrays * of contexts are no longer supported. * </p> * <p> * Thus the only valid parameter type for this method * is a <code>String</code> representing a context id. * The previously valid parameter types are deprecated. * The plural name for this method is unfortunate. * </p> * * @param contextIds the help context ids, or <code>null</code> if none * @see #getHelpContextIds */ public void setHelpContextIds(Object contextIds) { helpIds = contextIds; } /** * Sets the label provider for this property descriptor. * <p> * If no label provider is set an instance of <code>LabelProvider</code> * will be created as the default when needed. * </p> * * @param provider the label provider for the descriptor, or * <code>null</code> if the default label provider should be used * @see #getLabelProvider */ public void setLabelProvider(ILabelProvider provider) { labelProvider = provider; } /** * Sets the input validator for the cell editor for this property descriptor. * <p> * [Issue: This method should be unnecessary is the cell editor's own * validator is used. * ] * </p> * * @param validator the cell input validator, or <code>null</code> if none */ public void setValidator(ICellEditorValidator validator) { this.validator = validator; } }