TextBufferTracker (Oracle Fusion Middleware Java API Reference for Oracle Extension SDK)

A tracker of changes to the TextBuffer of a TextNode. A client which needs to track regions in a text buffer across edits can get a tracker for the text node, store the tracker version along with the offsets and lengths of the regions, and then at any time use the tracker to adjust offsets and lengths to reflect subsequent edits.

The text buffer uses text differencing to minimize the tracking impact of text buffer reloads which do not significantly change the text (e.g., minor external edits or VCS checkouts). The handling depends somewhat on undocumented text buffer implementation details. In particular, the tracker assumes that between RELOAD_STARTED and RELOAD_ENDED, the text buffer will issue a single remove event for the old text (unless the old text is empty), followed by a single insert event for the new text (unless the new text is empty).

Text buffers that are managed by TextNode may be garbage collected and later reloaded into a new text buffer which retains the listeners of the original text buffer. In this case, the tracker assumes that between the RELOAD_STARTED and RELOAD_ENDED, it will only see the insert event and not the remove event. To distinguish this case from a normal reload starting from an empty buffer, the tracker uses its history of the buffer length.

A text node that is closed without saving has to be tracked as a reversion, because if it is reopened every thing will be out of sync otherwise. The dirty flag is cleared by the time the nodeClosed event is fired, so the nodeWillClose event is used.

Field Summary
`static int`	`DEFAULT_COMPARISON_LIMIT`

Fields inherited from interface oracle.javatools.buffer.TextBufferListener
`EDIT_BEGIN_ATTRIBUTE, EDIT_END_ATTRIBUTE, EOL_TYPE_ATTRIBUTE, MODIFIED_ATTRIBUTE, READ_ONLY_ATTRIBUTE, RELOAD_END_ATTRIBUTE, RELOAD_START_ATTRIBUTE`

Method Summary
`boolean`	`adjustOffsetLength(int offset, int length, int version, int[] adjusted)` Adjusts a region of the tracked buffer to reflect modifications since a version.
`void`	`attributeUpdate(TextBuffer buffer, int attribute)` Provides notification regarding a change to one of the buffer attributes.
`static TextBufferTracker`	`createTrackerFromSnapshot(TextNode node, ReadTextBuffer snapshot, int comparisonLimit)` Creates a text buffer tracker for a text node with a specified snapshot as its initial version and the current node contents as the current version.
`static TextBufferTracker`	`getTracker(TextNode node)` Gets the text buffer tracker for a text node.
`java.net.URL`	`getURL()` Gets the URL of the tracked buffer.
`int`	`getVersion()` Gets the current version of the tracked buffer.
`void`	`insertUpdate(TextBuffer buffer, int offset, int count, char[] text)` Provides notification about an insertion into the `TextBuffer`.
`boolean`	`isModified(int version)` Gets whether the tracked buffer has been modified since a version.
`boolean`	`isModified(int offset, int length, int version)` Gets whether a region of the tracked buffer has been modified since a version.
`void`	`nodeClosed(NodeEvent event)` Called after a Node has been closed.
`void`	`nodeDeleted(NodeEvent e)` Called after a Node has been deleted from disk and removed from the NodeFactory cache.
`void`	`nodeDirtyStateChanged(NodeEvent e, boolean dirty)` Called when the dirty state of a Node has just changed.
`void`	`nodeOpened(NodeEvent event)` Called after a Node has been opened.
`void`	`nodeRenamed(NodeEvent e, java.net.URL oldURL, java.net.URL newURL)` Called after a Node has been renamed and recached under the new URL in the NodeFactory.
`void`	`nodeReverted(NodeEvent e)` Called when a Node has been reverted (reloaded) to its last saved state.
`void`	`nodeSaved(NodeEvent e)` Called after a Node has been saved.
`void`	`nodeWillBeSaved(NodeEvent e)` Called before a Node is about to be saved.
`void`	`nodeWillClose(NodeEvent e)` Called when a Node is about to be closed.
`void`	`nodeWillOpen(NodeEvent e)` Called when a Node is about to be opened.
`void`	`removeUpdate(TextBuffer buffer, int offset, int count, char[] text)` Provides notification about a removal from the `TextBuffer`.
`void`	`replaceText(TextBuffer buffer, char[] fromText, char[] toText, int comparisonLimit)`
`java.lang.String`	`toString()`

Methods inherited from class oracle.ide.model.NodeListener
`invokeLaterIfNeeded`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Field Detail

DEFAULT_COMPARISON_LIMIT

public static final int DEFAULT_COMPARISON_LIMIT

See Also:: Constant Field Values

Method Detail

getTracker

public static TextBufferTracker getTracker(TextNode node)

Gets the text buffer tracker for a text node. One tracker is created per node.

Parameters:: node - The TextNode to track.

createTrackerFromSnapshot

public static TextBufferTracker createTrackerFromSnapshot(TextNode node,
                                                          ReadTextBuffer snapshot,
                                                          int comparisonLimit)
                                                   throws java.io.IOException

Creates a text buffer tracker for a text node with a specified snapshot as its initial version and the current node contents as the current version.

A particular use case for this is where a source node is a template which is expanded for use at runtime and offsets are reported from the expanded version and need to be mapped back to the source.

Parameters:: node - The TextNode to track.
Throws:: java.io.IOException

getURL

public java.net.URL getURL()

Gets the URL of the tracked buffer.

Returns:

getVersion

public int getVersion()

Gets the current version of the tracked buffer. Note that this is not the change id of the buffer.

adjustOffsetLength

public boolean adjustOffsetLength(int offset,
                                  int length,
                                  int version,
                                  int[] adjusted)

Adjusts a region of the tracked buffer to reflect modifications since a version.

Parameters:: offset - The offset of the region when the version was current.; length - The length of the region when the version was current.; version - The version from which to adjust.; adjusted - A two element int array for the adjusted offset and length.
Returns:: true if the region contains changes since the version.

isModified

public boolean isModified(int version)

Gets whether the tracked buffer has been modified since a version.

Parameters:: version - The version from which to compare.

isModified

public boolean isModified(int offset,
                          int length,
                          int version)

Gets whether a region of the tracked buffer has been modified since a version.

Parameters:: offset - The offset of the region when the version was current.; length - The length of the region when the version was current.; version - The version from which to compare.
Returns:: true if the region as been modified since the version.
See Also:: adjustOffsetLength(int, int, int, int[])

toString

public java.lang.String toString()

Overrides:: toString in class java.lang.Object