JDK8/Java8源码在线阅读
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package javax.swing.text;
import java.util.Vector;
import java.io.Serializable;
import javax.swing.undo.*;
import javax.swing.SwingUtilities;
/**
* An implementation of the AbstractDocument.Content interface that is
* a brute force implementation that is useful for relatively small
* documents and/or debugging. It manages the character content
* as a simple character array. It is also quite inefficient.
* <p>
* It is generally recommended that the gap buffer or piece table
* implementations be used instead. This buffer does not scale up
* to large sizes.
* <p>
* <strong>Warning:</strong>
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeans™
* has been added to the <code>java.beans</code> package.
* Please see {@link java.beans.XMLEncoder}.
*
* @author Timothy Prinzing
*/
public final class StringContent implements AbstractDocument.Content, Serializable {
/**
* Creates a new StringContent object. Initial size defaults to 10.
*/
public StringContent() {
this(10);
}
/**
* Creates a new StringContent object, with the initial
* size specified. If the length is < 1, a size of 1 is used.
*
* @param initialLength the initial size
*/
public StringContent(int initialLength) {
if (initialLength < 1) {
initialLength = 1;
}
data = new char[initialLength];
data[0] = '\n';
count = 1;
}
/**
* Returns the length of the content.
*
* @return the length >= 1
* @see AbstractDocument.Content#length
*/
public int length() {
return count;
}
/**
* Inserts a string into the content.
*
* @param where the starting position >= 0 && < length()
* @param str the non-null string to insert
* @return an UndoableEdit object for undoing
* @exception BadLocationException if the specified position is invalid
* @see AbstractDocument.Content#insertString
*/
public UndoableEdit insertString(int where, String str) throws BadLocationException {
if (where >= count || where < 0) {
throw new BadLocationException("Invalid location", count);
}
char[] chars = str.toCharArray();
replace(where, 0, chars, 0, chars.length);
if (marks != null) {
updateMarksForInsert(where, str.length());
}
return new InsertUndo(where, str.length());
}
/**
* Removes part of the content. where + nitems must be < length().
*
* @param where the starting position >= 0
* @param nitems the number of characters to remove >= 0
* @return an UndoableEdit object for undoing
* @exception BadLocationException if the specified position is invalid
* @see AbstractDocument.Content#remove
*/
public UndoableEdit remove(int where, int nitems) throws BadLocationException {
if (where + nitems >= count) {
throw new BadLocationException("Invalid range", count);
}
String removedString = getString(where, nitems);
UndoableEdit edit = new RemoveUndo(where, removedString);
replace(where, nitems, empty, 0, 0);
if (marks != null) {
updateMarksForRemove(where, nitems);
}
return edit;
}
/**
* Retrieves a portion of the content. where + len must be <= length().
*
* @param where the starting position >= 0
* @param len the length to retrieve >= 0
* @return a string representing the content; may be empty
* @exception BadLocationException if the specified position is invalid
* @see AbstractDocument.Content#getString
*/
public String getString(int where, int len) throws BadLocationException {
if (where + len > count) {
throw new BadLocationException("Invalid range", count);
}
return new String(data, where, len);
}
/**
* Retrieves a portion of the content. where + len must be <= length()
*
* @param where the starting position >= 0
* @param len the number of characters to retrieve >= 0
* @param chars the Segment object to return the characters in
* @exception BadLocationException if the specified position is invalid
* @see AbstractDocument.Content#getChars
*/
public void getChars(int where, int len, Segment chars) throws BadLocationException {
if (where + len > count) {
throw new BadLocationException("Invalid location", count);
}
chars.array = data;
chars.offset = where;
chars.count = len;
}
/**
* Creates a position within the content that will
* track change as the content is mutated.
*
* @param offset the offset to create a position for >= 0
* @return the position
* @exception BadLocationException if the specified position is invalid
*/
public Position createPosition(int offset) throws BadLocationException {
// some small documents won't have any sticky positions
// at all, so the buffer is created lazily.
if (marks == null) {
marks = new Vector<PosRec>();
}
return new StickyPosition(offset);
}
// --- local methods ---------------------------------------
/**
* Replaces some of the characters in the array
* @param offset offset into the array to start the replace
* @param length number of characters to remove
* @param replArray replacement array
* @param replOffset offset into the replacement array
* @param replLength number of character to use from the
* replacement array.
*/
void replace(int offset, int length,
char[] replArray, int replOffset, int replLength) {
int delta = replLength - length;
int src = offset + length;
int nmove = count - src;
int dest = src + delta;
if ((count + delta) >= data.length) {
// need to grow the array
int newLength = Math.max(2*data.length, count + delta);
char[] newData = new char[newLength];
System.arraycopy(data, 0, newData, 0, offset);
System.arraycopy(replArray, replOffset, newData, offset, replLength);
System.arraycopy(data, src, newData, dest, nmove);
data = newData;
} else {
// patch the existing array
System.arraycopy(data, src, data, dest, nmove);
System.arraycopy(replArray, replOffset, data, offset, replLength);
}
count = count + delta;
}
void resize(int ncount) {
char[] ndata = new char[ncount];
System.arraycopy(data, 0, ndata, 0, Math.min(ncount, count));
data = ndata;
}
synchronized void updateMarksForInsert(int offset, int length) {
if (offset == 0) {
// zero is a special case where we update only
// marks after it.
offset = 1;
}
int n = marks.size();
for (int i = 0; i < n; i++) {
PosRec mark = marks.elementAt(i);
if (mark.unused) {
// this record is no longer used, get rid of it
marks.removeElementAt(i);
i -= 1;
n -= 1;
} else if (mark.offset >= offset) {
mark.offset += length;
}
}
}
synchronized void updateMarksForRemove(int offset, int length) {
int n = marks.size();
for (int i = 0; i < n; i++) {
PosRec mark = marks.elementAt(i);
if (mark.unused) {
// this record is no longer used, get rid of it
marks.removeElementAt(i);
i -= 1;
n -= 1;
} else if (mark.offset >= (offset + length)) {
mark.offset -= length;
} else if (mark.offset >= offset) {
mark.offset = offset;
}
}
}
/**
* Returns a Vector containing instances of UndoPosRef for the
* Positions in the range
* <code>offset</code> to <code>offset</code> + <code>length</code>.
* If <code>v</code> is not null the matching Positions are placed in
* there. The vector with the resulting Positions are returned.
* <p>
* This is meant for internal usage, and is generally not of interest
* to subclasses.
*
* @param v the Vector to use, with a new one created on null
* @param offset the starting offset >= 0
* @param length the length >= 0
* @return the set of instances
*/
protected Vector getPositionsInRange(Vector v, int offset,
int length) {
int n = marks.size();
int end = offset + length;
Vector placeIn = (v == null) ? new Vector() : v;
for (int i = 0; i < n; i++) {
PosRec mark = marks.elementAt(i);
if (mark.unused) {
// this record is no longer used, get rid of it
marks.removeElementAt(i);
i -= 1;
n -= 1;
} else if(mark.offset >= offset && mark.offset <= end)
placeIn.addElement(new UndoPosRef(mark));
}
return placeIn;
}
/**
* Resets the location for all the UndoPosRef instances
* in <code>positions</code>.
* <p>
* This is meant for internal usage, and is generally not of interest
* to subclasses.
*
* @param positions the positions of the instances
*/
protected void updateUndoPositions(Vector positions) {
for(int counter = positions.size() - 1; counter >= 0; counter--) {
UndoPosRef ref = (UndoPosRef)positions.elementAt(counter);
// Check if the Position is still valid.
if(ref.rec.unused) {
positions.removeElementAt(counter);
}
else
ref.resetLocation();
}
}
private static final char[] empty = new char[0];
private char[] data;
private int count;
transient Vector<PosRec> marks;
/**
* holds the data for a mark... separately from
* the real mark so that the real mark can be
* collected if there are no more references to
* it.... the update table holds only a reference
* to this grungy thing.
*/
final class PosRec {
PosRec(int offset) {
this.offset = offset;
}
int offset;
boolean unused;
}
/**
* This really wants to be a weak reference but
* in 1.1 we don't have a 100% pure solution for
* this... so this class trys to hack a solution
* to causing the marks to be collected.
*/
final class StickyPosition implements Position {
StickyPosition(int offset) {
rec = new PosRec(offset);
marks.addElement(rec);
}
public int getOffset() {
return rec.offset;
}
protected void finalize() throws Throwable {
// schedule the record to be removed later
// on another thread.
rec.unused = true;
}
public String toString() {
return Integer.toString(getOffset());
}
PosRec rec;
}
/**
* Used to hold a reference to a Position that is being reset as the
* result of removing from the content.
*/
final class UndoPosRef {
UndoPosRef(PosRec rec) {
this.rec = rec;
this.undoLocation = rec.offset;
}
/**
* Resets the location of the Position to the offset when the
* receiver was instantiated.
*/
protected void resetLocation() {
rec.offset = undoLocation;
}
/** Location to reset to when resetLocatino is invoked. */
protected int undoLocation;
/** Position to reset offset. */
protected PosRec rec;
}
/**
* UnoableEdit created for inserts.
*/
class InsertUndo extends AbstractUndoableEdit {
protected InsertUndo(int offset, int length) {
super();
this.offset = offset;
this.length = length;
}
public void undo() throws CannotUndoException {
super.undo();
try {
synchronized(StringContent.this) {
// Get the Positions in the range being removed.
if(marks != null)
posRefs = getPositionsInRange(null, offset, length);
string = getString(offset, length);
remove(offset, length);
}
} catch (BadLocationException bl) {
throw new CannotUndoException();
}
}
public void redo() throws CannotRedoException {
super.redo();
try {
synchronized(StringContent.this) {
insertString(offset, string);
string = null;
// Update the Positions that were in the range removed.
if(posRefs != null) {
updateUndoPositions(posRefs);
posRefs = null;
}
}
} catch (BadLocationException bl) {
throw new CannotRedoException();
}
}
// Where the string goes.
protected int offset;
// Length of the string.
protected int length;
// The string that was inserted. To cut down on space needed this
// will only be valid after an undo.
protected String string;
// An array of instances of UndoPosRef for the Positions in the
// range that was removed, valid after undo.
protected Vector posRefs;
}
/**
* UndoableEdit created for removes.
*/
class RemoveUndo extends AbstractUndoableEdit {
protected RemoveUndo(int offset, String string) {
super();
this.offset = offset;
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