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Eclipse Platform
Release 3.0

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org.eclipse.text.edits
Class TextEdit

java.lang.Object
  org.eclipse.text.edits.TextEdit

Direct Known Subclasses:

CopyingRangeMarker, CopySourceEdit, CopyTargetEdit, DeleteEdit, InsertEdit, MoveSourceEdit, MoveTargetEdit, MultiTextEdit, RangeMarker, ReplaceEdit, UndoEdit

public abstract class TextEdit

extends Object

A text edit describes an elementary text manipulation operation. Edits are executed by applying them to a document (e.g. an instance of IDocument ).

Text edits form a tree. Clients can navigate the tree upwards, from child to parent, as well as downwards. Newly created edits are unparented. New edits are added to the tree by calling one of the add methods on a parent edit.

An edit tree is well formed in the following sense:

• a parent edit covers all its children
• children don't overlap
• an edit with length 0 can't have any children

Any manipulation of the tree that violates one of the above requirements results in a MalformedTreeException.

Insert edits are represented by an edit of length 0. If more than one insert edit exists at the same offset then the edits are executed in the order in which they have been added to a parent. The following code example:

    IDocument document= new Document("org");
       MultiEdit edit= new MultiEdit();
    edit.add(new InsertEdit(0, "www.");
    edit.add(new InsertEdit(0, "eclipse.");
    edit.apply(document);
 

therefore results in string: "www.eclipse.org".

Text edits can be executed in a mode where the edit's region is updated to reflect the edit's position in the changed document. Region updating is enabled by default or can be requested by passing UPDATE_REGIONS to the apply(IDocument, int) method. In the above example the region of the InsertEdit(0, "eclipse.") edit after executing the root edit is [3, 8]. If the region of an edit got deleted during change execution the region is set to [-1, -1] and the method isDeleted returns true.

This class isn't intended to be subclassed outside of the edit framework. Clients are only allowed to subclass MultiTextEdit.

Since:

3.0

Field Summary

static int	CREATE_UNDO Flags indicating that applying an edit tree to a document is supposed to create a corresponding undo edit.
static int	NONE Flags indicating that either CREATE_UNDO nor UPDATE_REGIONS is set.
static int	UPDATE_REGIONS Flag indicating that the edit's region will be updated to reflect its position in the changed document.

Constructor Summary

protected	TextEdit(int offset, int length) Create a new text edit.
protected	TextEdit(TextEdit source) Copy constructor

Method Summary

void	accept(TextEditVisitor visitor) Accepts the given visitor on a visit of the current edit.
protected abstract void	accept0(TextEditVisitor visitor) Accepts the given visitor on a type-specific visit of the current edit.
protected void	acceptChildren(TextEditVisitor visitor) Accepts the given visitor on the edits children.
void	addChild(TextEdit child) Adds the given edit child to this edit.
void	addChildren(TextEdit[] edits) Adds all edits in edits to this edit.
UndoEdit	apply(IDocument document) Applies the edit tree rooted by this edit to the given document.
UndoEdit	apply(IDocument document, int style) Applies the edit tree rooted by this edit to the given document.
protected boolean	canZeroLengthCover() Returns true if an edit with length zero can cover another edit.
TextEdit	copy() Creates a deep copy of the edit tree rooted at this edit.
boolean	covers(TextEdit other) Returns true if the edit covers the given edit other.
protected abstract TextEdit	doCopy() Creates and returns a copy of this edit.
boolean	equals(Object obj) The Edit implementation of this Object method uses object identity (==).
TextEdit[]	getChildren() Returns the edit's children.
int	getChildrenSize() Returns the size of the managed children.
static IRegion	getCoverage(TextEdit[] edits) Returns the text range spawned by the given array of text edits.
int	getExclusiveEnd() Returns the exclusive end position of this edit.
int	getInclusiveEnd() Returns the inclusive end position of this edit.
int	getLength() Returns the length of the edit.
int	getOffset() Returns the offset of the edit.
TextEdit	getParent() Returns the edit's parent.
IRegion	getRegion() Returns the range that this edit is manipulating.
boolean	hasChildren() Returns true if this edit has children.
int	hashCode() The Edit implementation of this Object method calls uses Object#hashCode() to compute its hash code.
boolean	isDeleted() Returns whether this edit has been deleted or not.
protected void	postProcessCopy(TextEditCopier copier) This method is called on every edit of the copied tree to do some post-processing like connected an edit to a different edit in the tree.
TextEdit	removeChild(int index) Removes the edit specified by the given index from the list of children.
boolean	removeChild(TextEdit child) Removes the first occurrence of the given child from the list of children.
TextEdit[]	removeChildren() Removes all child edits from and returns them.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

NONE

public static final int NONE

Flags indicating that either CREATE_UNDO nor UPDATE_REGIONS is set.

See Also:

Constant Field Values

CREATE_UNDO

public static final int CREATE_UNDO

Flags indicating that applying an edit tree to a document is supposed to create a corresponding undo edit. If not specified null is returned from method apply.

See Also:

Constant Field Values

UPDATE_REGIONS

public static final int UPDATE_REGIONS

Flag indicating that the edit's region will be updated to reflect its position in the changed document. If not specified when applying an edit tree to a document the edit's region will be arbitrary. It is even not guaranteed that the tree is still well formed.

See Also:

Constant Field Values

Constructor Detail

TextEdit

protected TextEdit(int offset,
                   int length)

Create a new text edit. Parent is initialized to null and the edit doesn't have any children.

Parameters:

offset - the edit's offset

length - the edit's length

TextEdit

protected TextEdit(TextEdit source)

Copy constructor

Parameters:

source - the source to copy form

Method Detail

getRegion

public final IRegion getRegion()

Returns the range that this edit is manipulating. The returned IRegion contains the edit's offset and length at the point in time when this call is made. Any subsequent changes to the edit's offset and length aren't reflected in the returned region object.

Creating a region for a deleted edit will result in an assertion failure.

Returns:

the manipulated region

getOffset

public final int getOffset()

Returns the offset of the edit. An offset is a 0-based character index. Returns -1 if the edit is marked as deleted

Returns:

the offset of the edit

getLength

public final int getLength()

Returns the length of the edit. Returns -1 if the edit is marked as deleted.

Returns:

the length of the edit

getInclusiveEnd

public final int getInclusiveEnd()

Returns the inclusive end position of this edit. The inclusive end position denotes the last character of the region manipulated by this edit. The returned value is the result of the following calculation:

   getOffset() + getLength() - 1;
 



Returns:
the inclusive end position

getExclusiveEnd

public final int getExclusiveEnd()

Returns the exclusive end position of this edit. The exclusive end position denotes the next character of the region manipulated by this edit. The returned value is the result of the following calculation:

   getOffset() + getLength();
 

Returns:

the exclusive end position

isDeleted

public final boolean isDeleted()

Returns whether this edit has been deleted or not.

Returns:

true if the edit has been deleted; otherwise false is returned.

covers

public final boolean covers(TextEdit other)

Returns true if the edit covers the given edit other. It is up to the concrete text edit to decide if a edit of length zero can cover another edit.

Parameters:

other - the other edit

Returns:

true if the edit covers the other edit; otherwise false is returned.

canZeroLengthCover

protected boolean canZeroLengthCover()

Returns true if an edit with length zero can cover another edit. Returns false otherwise.

Returns:

whether an edit of length zero can cover another edit

getParent

public final TextEdit getParent()

Returns the edit's parent. The method returns null if this edit hasn't been add to another edit.

Returns:

the edit's parent

addChild

public final void addChild(TextEdit child)
                    throws MalformedTreeException

Adds the given edit child to this edit.

Parameters:

child - the child edit to add

Throws:

MalformedTreeException - is thrown if the child edit can't be added to this edit. This is the case if the child overlaps with one of its siblings or if the child edit's region isn't fully covered by this edit.

addChildren

public final void addChildren(TextEdit[] edits)
                       throws MalformedTreeException

Adds all edits in edits to this edit.

Parameters:

edits - the text edits to add

Throws:

MalformedTreeException - is thrown if one of the given edits can't be added to this edit.

See Also:

addChild(TextEdit)

removeChild

public final TextEdit removeChild(int index)

Removes the edit specified by the given index from the list of children. Returns the child edit that was removed from the list of children. The parent of the returned edit is set to null.

Parameters:

index - the index of the edit to remove

Returns:

the removed edit

Throws:

IndexOutOfBoundsException - if the index is out of range

removeChild

public final boolean removeChild(TextEdit child)

Removes the first occurrence of the given child from the list of children.

Parameters:

child - the child to be removed

Returns:

true if the edit contained the given child; otherwise false is returned

removeChildren

public final TextEdit[] removeChildren()

Removes all child edits from and returns them. The parent of the removed edits is set to null.

Returns:

an array of the removed edits

hasChildren

public final boolean hasChildren()

Returns true if this edit has children. Otherwise false is returned.

Returns:

true if this edit has children; otherwise false is returned

getChildren

public final TextEdit[] getChildren()

Returns the edit's children. If the edit doesn't have any children an empty array is returned.

Returns:

the edit's children

getChildrenSize

public final int getChildrenSize()

Returns the size of the managed children.

Returns:

the size of the children

getCoverage

public static IRegion getCoverage(TextEdit[] edits)

Returns the text range spawned by the given array of text edits. The method requires that the given array contains at least one edit. If all edits passed are deleted the method returns null.

Parameters:

edits - an array of edits

Returns:

the text range spawned by the given array of edits or null if all edits are marked as deleted

equals

public final boolean equals(Object obj)

The Edit implementation of this Object method uses object identity (==).

Parameters:

obj - the other object

Returns:

true iff this == obj; otherwise false is returned

See Also:

Object.equals(java.lang.Object)

hashCode

public final int hashCode()

The Edit implementation of this Object method calls uses Object#hashCode() to compute its hash code.

Returns:

the object's hash code value

See Also:

Object.hashCode()

toString

public String toString()

copy

public final TextEdit copy()

Creates a deep copy of the edit tree rooted at this edit.

Returns:

a deep copy of the edit tree

See Also:

doCopy()

doCopy

protected abstract TextEdit doCopy()

Creates and returns a copy of this edit. The copy method should be implemented in a way so that the copy can executed without causing any harm to the original edit. Implementors of this method are responsible for creating deep or shallow copies of referenced object to fullfil this requirement.

Implementers of this method should use the copy constructor Edit#Edit(Edit source) to initialize the edit part of the copy. Implementors aren't responsible to actually copy the children or to set the right parent.

This method should not be called from outside the framework. Please use copy to create a copy of a edit tree.

Returns:

a copy of this edit.

See Also:

copy(), postProcessCopy(TextEditCopier), TextEditCopier

postProcessCopy

protected void postProcessCopy(TextEditCopier copier)

This method is called on every edit of the copied tree to do some post-processing like connected an edit to a different edit in the tree.

This default implementation does nothing

Parameters:

copier - the copier that manages a map between original and copied edit.

See Also:

TextEditCopier

accept

public final void accept(TextEditVisitor visitor)

Accepts the given visitor on a visit of the current edit.

Parameters:

visitor - the visitor object

Throws:

IllegalArgumentException - if the visitor is null

accept0

protected abstract void accept0(TextEditVisitor visitor)

Accepts the given visitor on a type-specific visit of the current edit. This method must be implemented in all concrete text edits.

General template for implementation on each concrete TextEdit class:

 
 boolean visitChildren = visitor.visit(this);
 if (visitChildren) {
    acceptChildren(visitor);
 }
 
 

Note that the caller (accept) takes care of invoking visitor.preVisit(this) and visitor.postVisit(this).

Parameters:

visitor - the visitor object

acceptChildren

protected final void acceptChildren(TextEditVisitor visitor)

Accepts the given visitor on the edits children.

This method must be used by the concrete implementations of accept to traverse list-values properties; it encapsulates the proper handling of on-the-fly changes to the list.

Parameters:

visitor - the visitor object

apply

public final UndoEdit apply(IDocument document,
                            int style)
                     throws MalformedTreeException,
                            BadLocationException

Applies the edit tree rooted by this edit to the given document. To check if the edit tree can be applied to the document either catch MalformedTreeException or use TextEditProcessor to execute an edit tree.

Parameters:

document - the document to be manipulated

style - flags controlling the execution of the edit tree. Valid flags are: CREATE_UNDO and UPDATE_REGIONS.

Returns:

a undo edit, if CREATE_UNDO is specified. Otherwise null is returned.

Throws:

MalformedTreeException - is thrown if the tree isn't in a valid state. This exception is thrown before any edit is executed. So the document is still in its original state.

BadLocationException - is thrown if one of the edits in the tree can't be executed. The state of the document is undefined if this exception is thrown.

See Also:

TextEditProcessor.performEdits()

apply

public final UndoEdit apply(IDocument document)
                     throws MalformedTreeException,
                            BadLocationException

Applies the edit tree rooted by this edit to the given document. This method is a convenience method for apply(document, CREATE_UNDO | UPDATE_REGIONS)

Parameters:

document - the document to which to apply this edit

Returns:

a undo edit, if CREATE_UNDO is specified. Otherwise null is returned.

Throws:

MalformedTreeException - is thrown if the tree isn't in a valid state. This exception is thrown before any edit is executed. So the document is still in its original state.

BadLocationException - is thrown if one of the edits in the tree can't be executed. The state of the document is undefined if this exception is thrown.

See Also:

apply(IDocument, int)