1 /*******************************************************************************
2  * Copyright (c) 2000, 2017 IBM Corporation and others.
3  *
4  * This program and the accompanying materials
5  * are made available under the terms of the Eclipse Public License 2.0
6  * which accompanies this distribution, and is available at
7  * https://www.eclipse.org/legal/epl-2.0/
8  *
9  * SPDX-License-Identifier: EPL-2.0
10  *
11  * Contributors:
12  *     IBM Corporation - initial API and implementation
13  *******************************************************************************/
14 package org.eclipse.swt.dnd;
15 
16 import org.eclipse.swt.internal.cocoa.*;
17 
18 /**
19  * The class <code>TextTransfer</code> provides a platform specific mechanism
20  * for converting plain text represented as a java <code>String</code>
21  * to a platform specific representation of the data and vice versa.
22  *
23  * <p>An example of a java <code>String</code> containing plain text is shown
24  * below:</p>
25  *
26  * <pre><code>
27  *     String textData = "Hello World";
28  * </code></pre>
29  *
30  * <p>Note the <code>TextTransfer</code> does not change the content of the text
31  * data. For a better integration with the platform, the application should convert
32  * the line delimiters used in the text data to the standard line delimiter used by the
33  * platform.
34  * </p>
35  *
36  * @see Transfer
37  */
38 public class TextTransfer extends ByteArrayTransfer {
39 
40 	static TextTransfer _instance = new TextTransfer();
41 
42 	static final String ID_NAME = OS.NSPasteboardTypeString.getString();
43 	static final int ID = registerType(ID_NAME);
44 
TextTransfer()45 TextTransfer() {}
46 
47 /**
48  * Returns the singleton instance of the TextTransfer class.
49  *
50  * @return the singleton instance of the TextTransfer class
51  */
getInstance()52 public static TextTransfer getInstance () {
53 	return _instance;
54 }
55 
56 /**
57  * This implementation of <code>javaToNative</code> converts plain text
58  * represented by a java <code>String</code> to a platform specific representation.
59  *
60  * @param object a java <code>String</code> containing text
61  * @param transferData an empty <code>TransferData</code> object that will
62  *  	be filled in on return with the platform specific format of the data
63  *
64  * @see Transfer#nativeToJava
65  */
66 @Override
javaToNative(Object object, TransferData transferData)67 public void javaToNative (Object object, TransferData transferData) {
68 	if (!checkText(object) || !isSupportedType(transferData)) {
69 		DND.error(DND.ERROR_INVALID_DATA);
70 	}
71 	transferData.data = NSString.stringWith((String) object);
72 }
73 
74 /**
75  * This implementation of <code>nativeToJava</code> converts a platform specific
76  * representation of plain text to a java <code>String</code>.
77  *
78  * @param transferData the platform specific representation of the data to be converted
79  * @return a java <code>String</code> containing text if the conversion was successful; otherwise null
80  *
81  * @see Transfer#javaToNative
82  */
83 @Override
nativeToJava(TransferData transferData)84 public Object nativeToJava(TransferData transferData){
85 	if (!isSupportedType(transferData) || transferData.data == null) return null;
86 	NSString string = (NSString) transferData.data;
87 	return string.getString();
88 }
89 
90 @Override
getTypeIds()91 protected int[] getTypeIds() {
92 	return new int[] {ID};
93 }
94 
95 @Override
getTypeNames()96 protected String[] getTypeNames() {
97 	return new String[] {ID_NAME};
98 }
99 
checkText(Object object)100 boolean checkText(Object object) {
101 	return (object != null && object instanceof String && ((String)object).length() > 0);
102 }
103 @Override
validate(Object object)104 protected boolean validate(Object object) {
105 	return checkText(object);
106 }
107 }
108