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.
*
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package javax.swing.text;
import java.util.Vector;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import javax.swing.undo.AbstractUndoableEdit;
import javax.swing.undo.CannotRedoException;
import javax.swing.undo.CannotUndoException;
import javax.swing.undo.UndoableEdit;
import javax.swing.SwingUtilities;
import java.lang.ref.WeakReference;
import java.lang.ref.ReferenceQueue;
/**
* An implementation of the AbstractDocument.Content interface
* implemented using a gapped buffer similar to that used by emacs.
* The underlying storage is a array of unicode characters with
* a gap somewhere. The gap is moved to the location of changes
* to take advantage of common behavior where most changes are
* in the same location. Changes that occur at a gap boundary are
* generally cheap and moving the gap is generally cheaper than
* moving the array contents directly to accommodate the change.
* <p>
* The positions tracking change are also generally cheap to
* maintain. The Position implementations (marks) store the array
* index and can easily calculate the sequential position from
* the current gap location. Changes only require update to the
* the marks between the old and new gap boundaries when the gap
* is moved, so generally updating the marks is pretty cheap.
* The marks are stored sorted so they can be located quickly
* with a binary search. This increases the cost of adding a
* mark, and decreases the cost of keeping the mark updated.
*
* @author Timothy Prinzing
*/
public class GapContent extends GapVector implements AbstractDocument.Content, Serializable {
/**
* Creates a new GapContent object. Initial size defaults to 10.
*/
public GapContent() {
this(10);
}
/**
* Creates a new GapContent object, with the initial
* size specified. The initial size will not be allowed
* to go below 2, to give room for the implied break and
* the gap.
*
* @param initialLength the initial size
*/
public GapContent(int initialLength) {
super(Math.max(initialLength,2));
char[] implied = new char[1];
implied[0] = '\n';
replace(0, 0, implied, implied.length);
marks = new MarkVector();
search = new MarkData(0);
queue = new ReferenceQueue<StickyPosition>();
}
/**
* Allocate an array to store items of the type
* appropriate (which is determined by the subclass).
*/
protected Object allocateArray(int len) {
return new char[len];
}
/**
* Get the length of the allocated array.
*/
protected int getArrayLength() {
char[] carray = (char[]) getArray();
return carray.length;
}
// --- AbstractDocument.Content methods -------------------------
/**
* Returns the length of the content.
*
* @return the length >= 1
* @see AbstractDocument.Content#length
*/
public int length() {
int len = getArrayLength() - (getGapEnd() - getGapStart());
return len;
}
/**
* 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 > length() || where < 0) {
throw new BadLocationException("Invalid insert", length());
}
char[] chars = str.toCharArray();
replace(where, 0, chars, chars.length);
return new InsertUndo(where, str.length());
}
/**
* Removes part of the content.
*
* @param where the starting position >= 0, where + nitems < length()
* @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 >= length()) {
throw new BadLocationException("Invalid remove", length() + 1);
}
String removedString = getString(where, nitems);
UndoableEdit edit = new RemoveUndo(where, removedString);
replace(where, nitems, empty, 0);
return edit;
}
/**
* Retrieves a portion of the content.
*
* @param where the starting position >= 0
* @param len the length to retrieve >= 0
* @return a string representing the content
* @exception BadLocationException if the specified position is invalid
* @see AbstractDocument.Content#getString
*/
public String getString(int where, int len) throws BadLocationException {
Segment s = new Segment();
getChars(where, len, s);
return new String(s.array, s.offset, s.count);
}
/**
* Retrieves a portion of the content. If the desired content spans
* the gap, we copy the content. If the desired content does not
* span the gap, the actual store is returned to avoid the copy since
* it is contiguous.
*
* @param where the starting position >= 0, where + len <= length()
* @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 {
int end = where + len;
if (where < 0 || end < 0) {
throw new BadLocationException("Invalid location", -1);
}
if (end > length() || where > length()) {
throw new BadLocationException("Invalid location", length() + 1);
}
int g0 = getGapStart();
int g1 = getGapEnd();
char[] array = (char[]) getArray();
if ((where + len) <= g0) {
// below gap
chars.array = array;
chars.offset = where;
} else if (where >= g0) {
// above gap
chars.array = array;
chars.offset = g1 + where - g0;
} else {
// spans the gap
int before = g0 - where;
if (chars.isPartialReturn()) {
// partial return allowed, return amount before the gap
chars.array = array;
chars.offset = where;
chars.count = before;
return;
}
// partial return not allowed, must copy
chars.array = new char[len];
chars.offset = 0;
System.arraycopy(array, where, chars.array, 0, before);
System.arraycopy(array, g1, chars.array, before, len - before);
}
chars.count = len;
}
/**
* Creates a position within the content that will
* track change as the content is mutated.
*
* @param offset the offset to track >= 0
* @return the position
* @exception BadLocationException if the specified position is invalid
*/
public Position createPosition(int offset) throws BadLocationException {
while ( queue.poll() != null ) {
unusedMarks++;
}
if (unusedMarks > Math.max(5, (marks.size() / 10))) {
removeUnusedMarks();
}
int g0 = getGapStart();
int g1 = getGapEnd();
int index = (offset < g0) ? offset : offset + (g1 - g0);
search.index = index;
int sortIndex = findSortIndex(search);
MarkData m;
StickyPosition position;
if (sortIndex < marks.size()
&& (m = marks.elementAt(sortIndex)).index == index
&& (position = m.getPosition()) != null) {
//position references the correct StickyPostition
} else {
position = new StickyPosition();
m = new MarkData(index,position,queue);
position.setMark(m);
marks.insertElementAt(m, sortIndex);
}
return position;
}
/**
* Holds the data for a mark... separately from
* the real mark so that the real mark (Position
* that the caller of createPosition holds) can be
* collected if there are no more references to
* it. The update table holds only a reference
* to this data.
*/
final class MarkData extends WeakReference<StickyPosition> {
MarkData(int index) {
super(null);
this.index = index;
}
MarkData(int index, StickyPosition position, ReferenceQueue<? super StickyPosition> queue) {
super(position, queue);
this.index = index;
}
/**
* Fetch the location in the contiguous sequence
* being modeled. The index in the gap array
* is held by the mark, so it is adjusted according
* to it's relationship to the gap.
*/
public final int getOffset() {
int g0 = getGapStart();
int g1 = getGapEnd();
int offs = (index < g0) ? index : index - (g1 - g0);
return Math.max(offs, 0);
}
StickyPosition getPosition() {
return get();
}
int index;
}
final class StickyPosition implements Position {
StickyPosition() {
}
void setMark(MarkData mark) {
this.mark = mark;
}
public final int getOffset() {
return mark.getOffset();
}
public String toString() {
return Integer.toString(getOffset());
}
MarkData mark;
}
// --- variables --------------------------------------
private static final char[] empty = new char[0];
private transient MarkVector marks;
/**
* Record used for searching for the place to
* start updating mark indexs when the gap
* boundaries are moved.
*/
private transient MarkData search;
/**
* The number of unused mark entries
*/
private transient int unusedMarks = 0;
private transient ReferenceQueue<StickyPosition> queue;
final static int GROWTH_SIZE = 1024 * 512;
// --- gap management -------------------------------
/**
* Make the gap bigger, moving any necessary data and updating
* the appropriate marks
*/
protected void shiftEnd(int newSize) {
int oldGapEnd = getGapEnd();
super.shiftEnd(newSize);
// Adjust marks.
int dg = getGapEnd() - oldGapEnd;
int adjustIndex = findMarkAdjustIndex(oldGapEnd);
int n = marks.size();
for (int i = adjustIndex; i < n; i++) {
MarkData mark = marks.elementAt(i);
mark.index += dg;
}
}
/**
* Overridden to make growth policy less agressive for large
* text amount.
*/
int getNewArraySize(int reqSize) {
if (reqSize < GROWTH_SIZE) {
return super.getNewArraySize(reqSize);
} else {
return reqSize + GROWTH_SIZE;
}
}
/**
* Move the start of the gap to a new location,
* without changing the size of the gap. This
* moves the data in the array and updates the
* marks accordingly.
*/
protected void shiftGap(int newGapStart) {
int oldGapStart = getGapStart();
int dg = newGapStart - oldGapStart;
int oldGapEnd = getGapEnd();
int newGapEnd = oldGapEnd + dg;
int gapSize = oldGapEnd - oldGapStart;
// shift gap in the character array
super.shiftGap(newGapStart);
// update the marks
if (dg > 0) {
// Move gap up, move data and marks down.
int adjustIndex = findMarkAdjustIndex(oldGapStart);
int n = marks.size();
for (int i = adjustIndex; i < n; i++) {
MarkData mark = marks.elementAt(i);
if (mark.index >= newGapEnd) {
break;
}
mark.index -= gapSize;
}
} else if (dg < 0) {
// Move gap down, move data and marks up.
int adjustIndex = findMarkAdjustIndex(newGapStart);
int n = marks.size();
for (int i = adjustIndex; i < n; i++) {
MarkData mark = marks.elementAt(i);
if (mark.index >= oldGapEnd) {
break;
}
mark.index += gapSize;
}
}
resetMarksAtZero();
}
/**
* Resets all the marks that have an offset of 0 to have an index of
* zero as well.
*/
protected void resetMarksAtZero() {
if (marks != null && getGapStart() == 0) {
int g1 = getGapEnd();
for (int counter = 0, maxCounter = marks.size();
counter < maxCounter; counter++) {
MarkData mark = marks.elementAt(counter);
if (mark.index <= g1) {
mark.index = 0;
}
else {
break;
}
}
}
}
/**
* Adjust the gap end downward. This doesn't move
* any data, but it does update any marks affected
* by the boundary change. All marks from the old
* gap start down to the new gap start are squeezed
* to the end of the gap (their location has been
* removed).
*/
protected void shiftGapStartDown(int newGapStart) {
// Push aside all marks from oldGapStart down to newGapStart.
int adjustIndex = findMarkAdjustIndex(newGapStart);
int n = marks.size();
int g0 = getGapStart();
int g1 = getGapEnd();
for (int i = adjustIndex; i < n; i++) {
MarkData mark = marks.elementAt(i);
if (mark.index > g0) {
// no more marks to adjust
break;
}
mark.index = g1;
}
// shift the gap in the character array
super.shiftGapStartDown(newGapStart);
resetMarksAtZero();
}
/**
* Adjust the gap end upward. This doesn't move
* any data, but it does update any marks affected
* by the boundary change. All marks from the old
* gap end up to the new gap end are squeezed
* to the end of the gap (their location has been
* removed).
*/
protected void shiftGapEndUp(int newGapEnd) {
int adjustIndex = findMarkAdjustIndex(getGapEnd());
int n = marks.size();
for (int i = adjustIndex; i < n; i++) {
MarkData mark = marks.elementAt(i);
if (mark.index >= newGapEnd) {
break;
}
mark.index = newGapEnd;
}
// shift the gap in the character array
super.shiftGapEndUp(newGapEnd);
resetMarksAtZero();
}
/**
* Compares two marks.
*
* @param o1 the first object
* @param o2 the second object
* @return < 0 if o1 < o2, 0 if the same, > 0 if o1 > o2
*/
final int compare(MarkData o1, MarkData o2) {
if (o1.index < o2.index) {
return -1;
} else if (o1.index > o2.index) {
return 1;
} else {
return 0;
}
}
/**
* Finds the index to start mark adjustments given
* some search index.
*/
final int findMarkAdjustIndex(int searchIndex) {
search.index = Math.max(searchIndex, 1);
int index = findSortIndex(search);
// return the first in the series
// (ie. there may be duplicates).
for (int i = index - 1; i >= 0; i--) {
MarkData d = marks.elementAt(i);
if (d.index != search.index) {
break;
}
index -= 1;
}
return index;
}
/**
* Finds the index of where to insert a new mark.
*
* @param o the mark to insert
* @return the index
*/
final int findSortIndex(MarkData o) {
int lower = 0;
int upper = marks.size() - 1;
int mid = 0;
if (upper == -1) {
return 0;
}
int cmp;
MarkData last = marks.elementAt(upper);
cmp = compare(o, last);
if (cmp > 0)
return upper + 1;
while (lower <= upper) {
mid = lower + ((upper - lower) / 2);
MarkData entry = marks.elementAt(mid);
cmp = compare(o, entry);
if (cmp == 0) {
// found a match
return mid;
} else if (cmp < 0) {
upper = mid - 1;
} else {
lower = mid + 1;
}
}
// didn't find it, but we indicate the index of where it would belong.
return (cmp < 0) ? mid : mid + 1;
}
/**
* Remove all unused marks out of the sorted collection
* of marks.
*/
final void removeUnusedMarks() {
int n = marks.size();
MarkVector cleaned = new MarkVector(n);
for (int i = 0; i < n; i++) {
MarkData mark = marks.elementAt(i);
if (mark.get() != null) {
cleaned.addElement(mark);
}
}
marks = cleaned;
unusedMarks = 0;
}
static class MarkVector extends GapVector {
MarkVector() {
super();
}
MarkVector(int size) {
super(size);
}
/**
* Allocate an array to store items of the type
* appropriate (which is determined by the subclass).
*/
protected Object allocateArray(int len) {
return new MarkData[len];
}
/**
* Get the length of the allocated array
*/
protected int getArrayLength() {
MarkData[] marks = (MarkData[]) getArray();
return marks.length;
}
/**
* Returns the number of marks currently held
*/
public int size() {
int len = getArrayLength() - (getGapEnd() - getGapStart());
return len;
}
/**
* Inserts a mark into the vector
*/
public void insertElementAt(MarkData m, int index) {
oneMark[0] = m;
replace(index, 0, oneMark, 1);
}
/**
* Add a mark to the end
*/
public void addElement(MarkData m) {
insertElementAt(m, size());
}
/**
* Fetches the mark at the given index
*/
public MarkData elementAt(int index) {
int g0 = getGapStart();
int g1 = getGapEnd();
MarkData[] array = (MarkData[]) getArray();
if (index < g0) {
// below gap
return array[index];
} else {
// above gap
index += g1 - g0;
return array[index];
}
}
/**
* Replaces the elements in the specified range with the passed
* in objects. This will NOT adjust the gap. The passed in indices
* do not account for the gap, they are the same as would be used
* int <code>elementAt</code>.
*/
protected void replaceRange(int start, int end, Object[] marks) {
int g0 = getGapStart();
int g1 = getGapEnd();
int index = start;
int newIndex = 0;
Object[] array = (Object[]) getArray();
if (start >= g0) {
// Completely passed gap
index += (g1 - g0);
end += (g1 - g0);
}
else if (end >= g0) {
// straddles gap
end += (g1 - g0);
while (index < g0) {
array[index++] = marks[newIndex++];
}
index = g1;
}
else {
// below gap
while (index < end) {
array[index++] = marks[newIndex++];
}
}
while (index < end) {
array[index++] = marks[newIndex++];
}
}
MarkData[] oneMark = new MarkData[1];
}
// --- serialization -------------------------------------
private void readObject(ObjectInputStream s)
throws ClassNotFoundException, IOException {
s.defaultReadObject();
marks = new MarkVector();
search = new MarkData(0);
queue = new ReferenceQueue<StickyPosition>();
}
// --- undo support --------------------------------------
/**
* 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.
*
* @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 endOffset = offset + length;
int startIndex;
int endIndex;
int g0 = getGapStart();
int g1 = getGapEnd();
// Find the index of the marks.
if (offset < g0) {
if (offset == 0) {
// findMarkAdjustIndex start at 1!
startIndex = 0;
}
else {
startIndex = findMarkAdjustIndex(offset);
}
if (endOffset >= g0) {
endIndex = findMarkAdjustIndex(endOffset + (g1 - g0) + 1);
}
else {
endIndex = findMarkAdjustIndex(endOffset + 1);
}
}
else {
startIndex = findMarkAdjustIndex(offset + (g1 - g0));
endIndex = findMarkAdjustIndex(endOffset + (g1 - g0) + 1);
}
Vector placeIn = (v == null) ? new Vector(Math.max(1, endIndex -
startIndex)) : v;
for (int counter = startIndex; counter < endIndex; counter++) {
placeIn.addElement(new UndoPosRef(marks.elementAt(counter)));
}
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 UndoPosRef instances to reset
*/
protected void updateUndoPositions(Vector positions, int offset,
int length) {
// Find the indexs of the end points.
int endOffset = offset + length;
int g1 = getGapEnd();
int startIndex;
int endIndex = findMarkAdjustIndex(g1 + 1);
if (offset != 0) {
startIndex = findMarkAdjustIndex(g1);
}
else {
startIndex = 0;
}
// Reset the location of the refenences.
for(int counter = positions.size() - 1; counter >= 0; counter--) {
UndoPosRef ref = (UndoPosRef)positions.elementAt(counter);
ref.resetLocation(endOffset, g1);
}
// We have to resort the marks in the range startIndex to endIndex.
// We can take advantage of the fact that it will be in
// increasing order, accept there will be a bunch of MarkData's with
// the index g1 (or 0 if offset == 0) interspersed throughout.
if (startIndex < endIndex) {
Object[] sorted = new Object[endIndex - startIndex];
int addIndex = 0;
int counter;
if (offset == 0) {
// If the offset is 0, the positions won't have incremented,
// have to do the reverse thing.
// Find the elements in startIndex whose index is 0
for (counter = startIndex; counter < endIndex; counter++) {
MarkData mark = marks.elementAt(counter);
if (mark.index == 0) {
sorted[addIndex++] = mark;
}
}
for (counter = startIndex; counter < endIndex; counter++) {
MarkData mark = marks.elementAt(counter);
if (mark.index != 0) {
sorted[addIndex++] = mark;
}
}
}
else {
for (counter = startIndex; counter < endIndex; counter++) {
MarkData mark = marks.elementAt(counter);
if (mark.index != g1) {
sorted[addIndex++] = mark;
}
}
for (counter = startIndex; counter < endIndex; counter++) {
MarkData mark = marks.elementAt(counter);
if (mark.index == g1) {
sorted[addIndex++] = mark;
}
}
}
// And replace
marks.replaceRange(startIndex, endIndex, sorted);
}
}
/**
* Used to hold a reference to a Mark that is being reset as the
* result of removing from the content.
*/
final class UndoPosRef {
UndoPosRef(MarkData rec) {
this.rec = rec;
this.undoLocation = rec.getOffset();
}
/**
* Resets the location of the Position to the offset when the
* receiver was instantiated.
*
* @param endOffset end location of inserted string.
* @param g1 resulting end of gap.
*/
protected void resetLocation(int endOffset, int g1) {
if (undoLocation != endOffset) {
this.rec.index = undoLocation;
}
else {
this.rec.index = g1;
}
}
/** Previous Offset of rec. */
protected int undoLocation;
/** Mark to reset offset. */
protected MarkData rec;
} // End of GapContent.UndoPosRef
/**
* 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 {
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