Class ElementChangeRecorder
- java.lang.Object
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- org.eclipse.handly.model.impl.support.ElementChangeRecorder
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public class ElementChangeRecorder extends java.lang.Object
Records changes in the state of an element tree between two discrete points in time and produces a delta tree representing the changes.This implementation caches locally the state of an element tree at the time the recorder begins recording. When
endRecording()
is called, creates a delta tree over the cached state and the new state.Clients can use this class as it stands or subclass it as circumstances warrant.
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Constructor Summary
Constructors Constructor Description ElementChangeRecorder()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
beginRecording(IElement inputElement)
Begins recording changes in the element tree rooted at the given input element, reporting the changes to a new instance of default delta builder.void
beginRecording(IElement inputElement, IElementDeltaBuilder deltaBuilder)
Begins recording changes in the element tree rooted at the given input element, reporting the changes to the given delta builder.void
beginRecording(IElement inputElement, IElementDeltaBuilder deltaBuilder, int maxDepth)
Begins recording changes in the element tree rooted at the given input element for the specified maximum depth, reporting the changes to the given delta builder.IElementDeltaBuilder
endRecording()
Ends the current recording and returns a delta builder with the consolidated changes between the state of the element tree at the time the recording was started and its current state.protected void
findContentChange(java.lang.Object oldBody, java.lang.Object newBody, IElement element)
Finds whether the given element has had a content change.protected IElementDeltaBuilder
getDeltaBuilder()
Returns the current delta builder.protected IElement
getInputElement()
Returns the current input element.protected int
getMaxDepth()
Returns the current maximum depth.boolean
isRecording()
Returns whether this change recorder is currently recording.protected IElementDeltaBuilder
newDeltaBuilder(IElement element)
Returns a new instance of default delta builder rooted at the given element.protected void
recordBody(java.lang.Object body, IElement element)
Remembers the given body for the given element.
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Method Detail
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isRecording
public final boolean isRecording()
Returns whether this change recorder is currently recording.- Returns:
true
if this change recorder is recording, andfalse
otherwise
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beginRecording
public final void beginRecording(IElement inputElement)
Begins recording changes in the element tree rooted at the given input element, reporting the changes to a new instance of default delta builder. The delta builder is rooted at the given input element.- Parameters:
inputElement
- notnull
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beginRecording
public final void beginRecording(IElement inputElement, IElementDeltaBuilder deltaBuilder)
Begins recording changes in the element tree rooted at the given input element, reporting the changes to the given delta builder. The delta builder may benull
, in which case a new instance of default delta builder rooted at the given input element will be used.- Parameters:
inputElement
- notnull
deltaBuilder
- may benull
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beginRecording
public void beginRecording(IElement inputElement, IElementDeltaBuilder deltaBuilder, int maxDepth)
Begins recording changes in the element tree rooted at the given input element for the specified maximum depth, reporting the changes to the given delta builder. The delta builder may benull
, in which case a new instance of default delta builder rooted at the given input element will be used.- Parameters:
inputElement
- notnull
deltaBuilder
- may benull
maxDepth
- the maximum depth the recorder should look into (>= 0)
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endRecording
public IElementDeltaBuilder endRecording()
Ends the current recording and returns a delta builder with the consolidated changes between the state of the element tree at the time the recording was started and its current state.- Returns:
- a delta builder with the consolidated changes
(never
null
) - Throws:
java.lang.IllegalStateException
- if this recorder is not recording
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getInputElement
protected final IElement getInputElement()
Returns the current input element.- Returns:
- the current input element
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getDeltaBuilder
protected final IElementDeltaBuilder getDeltaBuilder()
Returns the current delta builder.- Returns:
- the current delta builder
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getMaxDepth
protected final int getMaxDepth()
Returns the current maximum depth.- Returns:
- the current maximum depth
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newDeltaBuilder
protected IElementDeltaBuilder newDeltaBuilder(IElement element)
Returns a new instance of default delta builder rooted at the given element.This implementation returns a new instance of
ElementDelta.Builder
. The root delta is created via theElementDelta.Factory
registered in the element's model context. If no delta factory is registered, a new instance ofElementDelta
is used.- Parameters:
element
- nevernull
- Returns:
- a new instance of default delta builder (never
null
)
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recordBody
protected void recordBody(java.lang.Object body, IElement element)
Remembers the given body for the given element. Subclasses may override this method, but must make sure to call the super implementation. This method is not intended to be invoked by subclasses.- Parameters:
body
- nevernull
element
- nevernull
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findContentChange
protected void findContentChange(java.lang.Object oldBody, java.lang.Object newBody, IElement element)
Finds whether the given element has had a content change. Subclasses may override this method, but are not intended to invoke it.Implementations can compare the given bodies and, if there are differences (excepting children), insert an appropriate change delta (such as
F_CONTENT
) for the given element into the delta tree being built. Implementations should not take changes in children into account.This implementation invokes
((Body)newBody).
.findContentChange
((Body)oldBody, element, getDeltaBuilder())- Parameters:
oldBody
- the old version of the element's body (nevernull
)newBody
- the new version of the element's body (nevernull
)element
- the element whose bodies are to be compared (nevernull
)
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