1 /*
   2  * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javafx.scene.input;
  27 
  28 import java.util.Arrays;
  29 import java.util.Collections;
  30 import java.util.HashSet;
  31 import java.util.Iterator;
  32 import java.util.Set;
  33 
  34 import com.sun.javafx.util.WeakReferenceQueue;
  35 import javafx.beans.NamedArg;
  36 
  37 /**
  38  * Data format identifier used as means
  39  * of identifying the data stored on a clipboard/dragboard.
  40  * @since JavaFX 2.0
  41  */
  42 public class DataFormat {
  43 
  44     /**
  45      * A static cache of all DataFormats created and currently in use. This is needed
  46      * by the underlying implementation, such that, given a mime type, we can determine
  47      * the associated DataFormat. The OS level is going to supply us with a mime type
  48      * (or other string based key), and we need to be able to map this back to the FX
  49      * DataFormat.
  50      */
  51     private static final WeakReferenceQueue<DataFormat> DATA_FORMAT_LIST = new WeakReferenceQueue<DataFormat>();
  52 
  53     /**
  54      * Represents a plain text string.
  55      */
  56     public static final DataFormat PLAIN_TEXT = new DataFormat("text/plain");
  57 
  58     /**
  59      * Represents an HTML formatted string.
  60      */
  61     public static final DataFormat HTML = new DataFormat("text/html");
  62 
  63     /**
  64      * Represents an RTF formatted string
  65      */
  66     public static final DataFormat RTF = new DataFormat("text/rtf");
  67 
  68     /**
  69      * Represents a URL, encoded as a String
  70      */
  71     public static final DataFormat URL = new DataFormat("text/uri-list");
  72 
  73     /**
  74      * A special platform specific image type, such as is commonly used
  75      * on the clipboard and interoperates widely with other applications.
  76      * For example, on Mac this might ultimately be a TIFF while on
  77      * Windows it might be a DIB (device independent bitmap).
  78      */
  79     public static final DataFormat IMAGE = new DataFormat("application/x-java-rawimage");
  80 
  81     /**
  82      * Represents a List of Files.
  83      */
  84     public static final DataFormat FILES = new DataFormat("application/x-java-file-list", "java.file-list");
  85 
  86     /**
  87      * Data format used internally, represents dragged image. Making this
  88      * a private field prevents user from creating this DataFormat and breaking
  89      * our drag view implementation.
  90      */
  91     private static final DataFormat DRAG_IMAGE = new DataFormat("application/x-java-drag-image");
  92 
  93     /**
  94      * Data format used internally, represents offset in the dragged image.
  95      * Making this a private field prevents user from creating this DataFormat
  96      * and breaking our drag view implementation.
  97      */
  98     private static final DataFormat DRAG_IMAGE_OFFSET = new DataFormat("application/x-java-drag-image-offset");
  99     
 100     /**
 101      * A set of identifiers, typically mime types, for this DataFormat. 
 102      * In most cases this will be a single String.
 103      */
 104     private final Set<String> identifier;
 105 
 106     /**
 107      * Create a new DataFormat, specifying the set of ids that are associated with
 108      * this data format. Typically the ids are one or more mime types. For each 
 109      * id, any data associated with this DataFormat will be registered on the 
 110      * clipboard. For example, suppose I had the following:
 111      * <pre><code>
 112      *     DataFormat fmt = new DataFormat("text/foo", "text/bar");
 113      *     Clipboard clipboard = Clipboard.getSystemClipboard();
 114      *     ClipboardContent content = new ClipboardContent();
 115      *     content.put(fmt, "Hello");
 116      *     clipboard.setContent(content);
 117      * </code></pre>
 118      *
 119      * With the above code, if I were to look on the clipboard, I'd find the String "Hello"
 120      * listed both for "text/foo" and "text/bar" on the clipboard.
 121      *
 122      * <p>
 123      * Note that the ids may be subject to platform restrictions in some cases.
 124      * For instance, Swing requires a mime type so if an {@code id} is not
 125      * of the "type/subtype" format it won't be possible
 126      * to drag data of this type from/to {@link javafx.embed.swing.JFXPanel}.
 127      * </p>
 128      * @param ids The set of ids used to represent this DataFormat on the clipboard.
 129      * @throws IllegalArgumentException if one of the given mime types is already
 130      *         assigned to another DataFormat.
 131      */
 132     public DataFormat(@NamedArg("ids") String... ids) {
 133         DATA_FORMAT_LIST.cleanup();
 134         if (ids != null) {
 135             for (String id : ids) {
 136                 if (lookupMimeType(id) != null) {
 137                     throw new IllegalArgumentException("DataFormat '" + id +
 138                             "' already exists.");
 139                 }
 140             }
 141             this.identifier = Collections.unmodifiableSet(new HashSet<String>(Arrays.asList(ids)));
 142         } else {
 143             this.identifier = Collections.<String>emptySet();
 144         }
 145 
 146         // Add to the statis data format list.
 147         DATA_FORMAT_LIST.add(this);
 148     }
 149 
 150     /**
 151      * Gets the unmodifiable set of identifiers for this DataFormat.
 152      * @return an unmodifiable set that is never null.
 153      */
 154     public final Set<String> getIdentifiers() {
 155         return identifier;
 156     }
 157     
 158     /**
 159      * Returns a string representation of this {@code DataFormat} object.
 160      * @return a string representation of this {@code DataFormat} object.
 161      */ 
 162     @Override public String toString() {
 163         if (identifier.isEmpty()) {
 164             return "[]";
 165         } else if (identifier.size() == 1) {
 166             StringBuilder sb = new StringBuilder("[");
 167             sb.append(identifier.iterator().next());
 168             return (sb.append("]").toString());
 169         } else {
 170             StringBuilder b = new StringBuilder("[");
 171             Iterator<String> itr = identifier.iterator();
 172             while (itr.hasNext()) {
 173                 b = b.append(itr.next());
 174                 if (itr.hasNext()) {
 175                     b = b.append(", ");
 176                 }
 177             }
 178             b = b.append("]");
 179             return b.toString();
 180         }
 181     }
 182 
 183     /**
 184      * Returns a hash code for this {@code DataFormat} object.
 185      * @return a hash code for this {@code DataFormat} object.
 186      */
 187     @Override public int hashCode() {
 188         int hash = 7;
 189 
 190         for (String id : identifier) {
 191             hash = 31 * hash + id.hashCode();
 192         }
 193 
 194         return hash;
 195     }
 196 
 197     /**
 198      * Indicates whether some other object is "equal to" this one.
 199      * @param obj the reference object with which to compare.
 200      * @return {@code true} if this object is equal to the {@code obj} argument; {@code false} otherwise.
 201      */
 202     @Override public boolean equals(Object obj) {
 203         if (obj == null || ! (obj instanceof DataFormat)) {
 204             return false;
 205         }
 206 
 207         DataFormat otherDataFormat = (DataFormat) obj;
 208 
 209         if (identifier.equals(otherDataFormat.identifier)) {
 210             return true;
 211         }
 212 
 213         return false;
 214     }
 215 
 216     /**
 217      * Looks for the DataFormat which has been previously created with
 218      * the given mime type as one of its ids.
 219      * @param mimeType If null or the empty string, then null is returned.
 220      * @return The matching DataFormat
 221      */
 222     public static DataFormat lookupMimeType(String mimeType) {
 223         if (mimeType == null || mimeType.length() == 0) {
 224             return null;
 225         }
 226 
 227         Iterator itr = DATA_FORMAT_LIST.iterator();
 228         while (itr.hasNext()) {
 229             DataFormat dataFormat = (DataFormat) itr.next();
 230             if (dataFormat.getIdentifiers().contains(mimeType)) {
 231                 return dataFormat;
 232             }
 233         }
 234         return null;
 235     }
 236 }