org.fife.ui.rtextarea.RTATextTransferHandler Maven / Gradle / Ivy
The newest version!
/*
* 07/29/2004
*
* RTATextTransferHandler.java - Handles the transfer of data to/from an
* RTextArea via drag-and-drop.
*
* This library is distributed under a modified BSD license. See the included
* RSyntaxTextArea.License.txt file for details.
*/
package org.fife.ui.rtextarea;
import java.awt.datatransfer.*;
import java.awt.im.InputContext;
import java.io.InputStream;
import java.io.IOException;
import java.io.Reader;
import java.io.StringBufferInputStream;
import java.io.StringReader;
import javax.swing.*;
import javax.swing.text.*;
/**
* Handles the transfer of data to/from an RTextArea via
* drag-and-drop. This class is pretty much ripped off from a subclass of
* BasicTextUI. In the future, it will include the ability to
* drag-and-drop files into RTextAreas (i.e., the text will be
* inserted into the text area).
*
* The main reason this class is kept around is so we can subclass it.
*
* @author Robert Futrell
* @version 0.1
*/
public class RTATextTransferHandler extends TransferHandler {
private JTextComponent exportComp;
private boolean shouldRemove;
private int p0;
private int p1;
private boolean withinSameComponent;
/**
* Try to find a flavor that can be used to import a Transferable to a
* specified text component.
* The set of usable flavors are tried in the following order:
*
* - First, an attempt is made to find a flavor matching the content
* tyep of the EditorKit for the component.
*
- Second, an attempt to find a text/plain flavor is made.
*
- Third, an attempt to find a flavor representing a String
* reference in the same VM is made.
*
- Lastly, DataFlavor.stringFlavor is searched for.
*
*
* @param flavors The flavors to check if c will accept them.
* @param c The text component to see whether it will accept any of the
* specified data flavors as input.
*/
protected DataFlavor getImportFlavor(DataFlavor[] flavors,
JTextComponent c) {
DataFlavor refFlavor = null;
DataFlavor stringFlavor = null;
for (int i = 0; i < flavors.length; i++) {
String mime = flavors[i].getMimeType();
if (mime.startsWith("text/plain")) {
return flavors[i];
}
else if (refFlavor == null
&& mime.startsWith("application/x-java-jvm-local-objectref")
&& flavors[i].getRepresentationClass() == String.class)
{
refFlavor = flavors[i];
}
else if (stringFlavor==null &&
flavors[i].equals(DataFlavor.stringFlavor))
{
stringFlavor = flavors[i];
}
}
if (refFlavor != null)
return refFlavor;
else if (stringFlavor != null)
return stringFlavor;
return null;
}
/**
* Import the given stream data into the text component.
*/
protected void handleReaderImport(Reader in, JTextComponent c)
throws BadLocationException, IOException {
char[] buff = new char[1024];
int nch;
boolean lastWasCR = false;
int last;
StringBuilder sbuff = null;
// Read in a block at a time, mapping \r\n to \n, as well as single
// \r to \n.
while ((nch = in.read(buff, 0, buff.length)) != -1) {
if (sbuff == null) {
sbuff = new StringBuilder(nch);
}
last = 0;
for (int counter = 0; counter < nch; counter++) {
switch (buff[counter]) {
case '\r':
if (lastWasCR) {
if (counter == 0)
sbuff.append('\n');
else
buff[counter - 1] = '\n';
}
else
lastWasCR = true;
break;
case '\n':
if (lastWasCR) {
if (counter > (last + 1))
sbuff.append(buff, last, counter - last - 1);
// else nothing to do, can skip \r, next write will
// write \n
lastWasCR = false;
last = counter;
}
break;
default:
if (lastWasCR) {
if (counter == 0)
sbuff.append('\n');
else
buff[counter - 1] = '\n';
lastWasCR = false;
}
break;
} // End fo switch (buff[counter]).
} // End of for (int counter = 0; counter < nch; counter++).
if (last < nch) {
if (lastWasCR) {
if (last < (nch - 1))
sbuff.append(buff, last, nch - last - 1);
}
else
sbuff.append(buff, last, nch - last);
}
} // End of while ((nch = in.read(buff, 0, buff.length)) != -1).
if (withinSameComponent) {
((RTextArea)c).beginAtomicEdit();
}
if (lastWasCR)
sbuff.append('\n');
c.replaceSelection(sbuff != null ? sbuff.toString() : "");
}
/**
* This is the type of transfer actions supported by the source. Some
* models are not mutable, so a transfer operation of COPY only should
* be advertised in that case.
*
* @param c The component holding the data to be transfered. This
* argument is provided to enable sharing of TransferHandlers by
* multiple components.
* @return If the text component is editable, COPY_OR_MOVE is returned,
* otherwise just COPY is allowed.
*/
@Override
public int getSourceActions(JComponent c) {
if (((JTextComponent)c).isEditable())
return COPY_OR_MOVE;
else
return COPY;
}
/**
* Create a Transferable to use as the source for a data transfer.
*
* @param comp The component holding the data to be transfered. This
* argument is provided to enable sharing of TransferHandlers by
* multiple components.
* @return The representation of the data to be transfered.
*
*/
@Override
protected Transferable createTransferable(JComponent comp) {
exportComp = (JTextComponent)comp;
shouldRemove = true;
p0 = exportComp.getSelectionStart();
p1 = exportComp.getSelectionEnd();
return (p0 != p1) ? (new TextTransferable(exportComp, p0, p1)) : null;
}
/**
* This method is called after data has been exported. This method should
* remove the data that was transfered if the action was MOVE.
*
* @param source The component that was the source of the data.
* @param data The data that was transferred or possibly null
* if the action is NONE.
* @param action The actual action that was performed.
*/
@Override
protected void exportDone(JComponent source, Transferable data, int action) {
// only remove the text if shouldRemove has not been set to
// false by importData and only if the action is a move
if (shouldRemove && action == MOVE) {
TextTransferable t = (TextTransferable)data;
t.removeText();
if (withinSameComponent) {
((RTextArea)source).endAtomicEdit();
withinSameComponent = false;
}
}
exportComp = null;
if (data instanceof TextTransferable) {
ClipboardHistory.get().add(((TextTransferable)data).getPlainData());
}
}
/**
* This method causes a transfer to a component from a clipboard or a
* DND drop operation. The Transferable represents the data to be
* imported into the component.
*
* @param comp The component to receive the transfer. This
* argument is provided to enable sharing of TransferHandlers by
* multiple components.
* @param t The data to import
* @return true iff the data was inserted into the component.
*/
@Override
public boolean importData(JComponent comp, Transferable t) {
JTextComponent c = (JTextComponent)comp;
withinSameComponent = c==exportComp;
// if we are importing to the same component that we exported from
// then don't actually do anything if the drop location is inside
// the drag location and set shouldRemove to false so that exportDone
// knows not to remove any data
if (withinSameComponent && c.getCaretPosition()>=p0 && c.getCaretPosition()<=p1) {
shouldRemove = false;
return true;
}
boolean imported = false;
DataFlavor importFlavor = getImportFlavor(t.getTransferDataFlavors(), c);
if (importFlavor != null) {
try {
InputContext ic = c.getInputContext();
if (ic != null)
ic.endComposition();
Reader r = importFlavor.getReaderForText(t);
handleReaderImport(r, c);
imported = true;
} catch (UnsupportedFlavorException ufe) {
ufe.printStackTrace();
} catch (BadLocationException ble) {
ble.printStackTrace();
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
return imported;
}
/**
* This method indicates if a component would accept an import of the
* given set of data flavors prior to actually attempting to import it.
*
* @param comp The component to receive the transfer. This argument is
* provided to enable sharing of TransferHandlers by multiple
* components.
* @param flavors The data formats available.
* @return true iff the data can be inserted.
*/
@Override
public boolean canImport(JComponent comp, DataFlavor[] flavors) {
JTextComponent c = (JTextComponent)comp;
if (!(c.isEditable() && c.isEnabled()))
return false;
return (getImportFlavor(flavors, c) != null);
}
/**
* A possible implementation of the Transferable interface for RTextAreas.
*/
static class TextTransferable implements Transferable {
Position p0;
Position p1;
JTextComponent c;
protected String plainData;
private static DataFlavor[] stringFlavors;
private static DataFlavor[] plainFlavors;
TextTransferable(JTextComponent c, int start, int end) {
this.c = c;
Document doc = c.getDocument();
try {
p0 = doc.createPosition(start);
p1 = doc.createPosition(end);
plainData = c.getSelectedText();
} catch (BadLocationException ble) {
}
}
/**
* Fetch the data in a text/plain format.
*/
protected String getPlainData() {
return plainData;
}
/**
* Returns an object which represents the data to be transferred. The class
* of the object returned is defined by the representation class of the flavor.
*
* @param flavor the requested flavor for the data
* @see DataFlavor#getRepresentationClass
* @exception IOException if the data is no longer available
* in the requested flavor.
* @exception UnsupportedFlavorException if the requested data flavor is
* not supported.
*/
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
if (isPlainFlavor(flavor)) {
String data = getPlainData();
data = (data == null) ? "" : data;
if (String.class.equals(flavor.getRepresentationClass())) {
return data;
} else if (Reader.class.equals(flavor.getRepresentationClass())) {
return new StringReader(data);
} else if (InputStream.class.equals(flavor.getRepresentationClass())) {
return new StringBufferInputStream(data);
}
// fall through to unsupported
} else if (isStringFlavor(flavor)) {
String data = getPlainData();
data = (data == null) ? "" : data;
return data;
}
throw new UnsupportedFlavorException(flavor);
}
/**
* Returns an array of DataFlavor objects indicating the flavors the data
* can be provided in. The array should be ordered according to preference
* for providing the data (from most richly descriptive to least descriptive).
*
* @return an array of data flavors in which this data can be transferred
*/
public DataFlavor[] getTransferDataFlavors() {
int plainCount = (isPlainSupported()) ? plainFlavors.length: 0;
int stringCount = (isPlainSupported()) ? stringFlavors.length : 0;
int totalCount = plainCount + stringCount;
DataFlavor[] flavors = new DataFlavor[totalCount];
// fill in the array
int pos = 0;
if (plainCount > 0) {
System.arraycopy(plainFlavors, 0, flavors, pos, plainCount);
pos += plainCount;
}
if (stringCount > 0) {
System.arraycopy(stringFlavors, 0, flavors, pos, stringCount);
//pos += stringCount;
}
return flavors;
}
/**
* Returns whether or not the specified data flavor is supported for
* this object.
* @param flavor the requested flavor for the data
* @return boolean indicating whether or not the data flavor is supported
*/
public boolean isDataFlavorSupported(DataFlavor flavor) {
DataFlavor[] flavors = getTransferDataFlavors();
for (int i = 0; i < flavors.length; i++) {
if (flavors[i].equals(flavor))
return true;
}
return false;
}
/**
* Returns whether or not the specified data flavor is an plain flavor that
* is supported.
* @param flavor the requested flavor for the data
* @return boolean indicating whether or not the data flavor is supported
*/
protected boolean isPlainFlavor(DataFlavor flavor) {
DataFlavor[] flavors = plainFlavors;
for (int i = 0; i < flavors.length; i++) {
if (flavors[i].equals(flavor))
return true;
}
return false;
}
/**
* Should the plain text flavors be offered? If so, the method
* getPlainData should be implemented to provide something reasonable.
*/
protected boolean isPlainSupported() {
return plainData != null;
}
/**
* Returns whether or not the specified data flavor is a String flavor that
* is supported.
* @param flavor the requested flavor for the data
* @return boolean indicating whether or not the data flavor is supported
*/
protected boolean isStringFlavor(DataFlavor flavor) {
DataFlavor[] flavors = stringFlavors;
for (int i = 0; i < flavors.length; i++) {
if (flavors[i].equals(flavor))
return true;
}
return false;
}
void removeText() {
if ((p0 != null) && (p1 != null) && (p0.getOffset() != p1.getOffset())) {
try {
Document doc = c.getDocument();
doc.remove(p0.getOffset(), p1.getOffset() - p0.getOffset());
} catch (BadLocationException e) {
}
}
}
// Initialization of supported flavors.
static {
try {
plainFlavors = new DataFlavor[3];
plainFlavors[0] = new DataFlavor("text/plain;class=java.lang.String");
plainFlavors[1] = new DataFlavor("text/plain;class=java.io.Reader");
plainFlavors[2] = new DataFlavor("text/plain;charset=unicode;class=java.io.InputStream");
stringFlavors = new DataFlavor[2];
stringFlavors[0] = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType+";class=java.lang.String");
stringFlavors[1] = DataFlavor.stringFlavor;
} catch (ClassNotFoundException cle) {
System.err.println("Error initializing org.fife.ui.RTATextTransferHandler");
}
}
}
}