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...	...	@@ -125,7 +125,7 @@
125	125	The next task consists of creating a view that is able to display the state of a Turing Machine. We will do this using a table with one column, where each row represents an entry on the tape of the Turing Machine. The tape shall be infinite to one side, and the position of the read/write head shall be movable by two buttons. The content of the tape shall be determined by the currently active instance of our simple text editor.
126	126
127	127	{{info title="Hint"}}
128		-In this tutorial, we will be making use of the Standard Widget Toolkit (SWT) and JFace to build a user interface. It might be a good idea now to search for an introduction to SWT and JFace concepts on the Internet before you proceed.
	128	+In the following, we will be making use of the Standard Widget Toolkit (SWT) and JFace to build a user interface. It might be a good idea now to search for an introduction to SWT and JFace concepts on the Internet before you proceed.
129	129	{{/info}}
130	130
131	131	== Creating the View Class ==
...	...	@@ -192,8 +192,35 @@
192	192	1*. For {{code language="none"}}pos > text.length(){{/code}}, return the character {{code language="none"}}BLANK_CHAR{{/code}}.
193	193	1*. Otherwise, return the text character at index {{code language="none"}}pos - 1{{/code}}.
194	194	1. Add a private field tape of type {{code language="none"}}TuringTape{{/code}} to {{code language="none"}}TapeViewPart{{/code}} and initialize it with a new instance.
195		-1. Create a class {{code language="none"}}TapeData{{/code}} in {{code language="none"}}de.cau.cs.rtprak.login.simple.views{{/code}} with two fields {{code language="none"}}int index{{/code}} and {{code language="none"}}char character{{/code}}, and add a constructor for initialization as well as corresponding getter methods.
	195	+1. Create a class {{code language="none"}}TapeData{{/code}} in {{code language="none"}}de.cau.cs.rtprak.login.simple.model{{/code}} with two fields {{code language="none"}}int index{{/code}} and {{code language="none"}}char character{{/code}}, and add a constructor for initialization as well as corresponding getter methods.
	196	+1. Create a class {{code language="none"}}TapeContentProvider{{/code}} in the {{code language="none"}}de.cau.cs.rtprak.login.simple.views{{/code}} package that implements [[IStructuredContentProvider>>url:http://help.eclipse.org/juno/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/jface/viewers/IStructuredContentProvider.html||shape="rect"]].\\
	197	+1*. The methods {{code language="none"}}dispose(){{/code}} and {{code language="none"}}inputChanged(){{/code}} may remain empty.
	198	+1*. The method {{code language="none"}}getElements(){{/code}} must return an array of objects, where each object must contain all necessary data to be displayed in a single row of the table. The number of returned objects corresponds to the number of rows.
	199	+1*. Suppose the input element is an instance of {{code language="none"}}TuringTape{{/code}}. The result of {{code language="none"}}getElements(){{/code}} shall be an array of {{code language="none"}}TapeData{{/code}} elements. The size of the array shall be one more than the maximum of the tape head position and the length of the tape text. The index and character of each tape data element shall be filled with {{code language="none"}}i{{/code}} and the result of {{code language="none"}}turingTape.getCharacter(i){{/code}}, respectively, where {{code language="none"}}i{{/code}} is the array index of the element.
	200	+1. Create a class {{code language="none"}}TapeLabelProvider{{/code}} in the {{code language="none"}}de.cau.cs.rtprak.login.simple.views{{/code}} package that extends [[BaseLabelProvider>>url:http://help.eclipse.org/juno/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/jface/viewers/BaseLabelProvider.html||shape="rect"]] and implements [[ITableLabelProvider>>url:http://help.eclipse.org/juno/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/jface/viewers/ITableLabelProvider.html||shape="rect"]].\\
	201	+1*. Add a private field tape of type {{code language="none"}}TuringTape{{/code}} that is initialized from the constructor.
	202	+1*. Add fields {{code language="none"}}presentImage{{/code}} and {{code language="none"}}absentImage{{/code}} of type [[Image>>url:http://help.eclipse.org/juno/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/graphics/Image.html||shape="rect"]].
	203	+1*. (((
	204	+Initialize each image using the following code, where {{code language="none"}}path_to_image{{/code}} is {{code language="none"}}icons/head_present.gif{{/code}} and {{code language="none"}}icons/head_absent.gif{{/code}}, respectively:
196	196
	206	+{{code language="java"}}
	207	+image = Activator.imageDescriptorFromPlugin(Activator.PLUGIN_ID, "path_to_image").createImage();
	208	+{{/code}}
	209	+)))
	210	+1*. Override the implementation of {{code language="none"}}dispose(){{/code}} in {{code language="none"}}TapeLabelProvider{{/code}} to dispose both images after calling {{code language="none"}}super.dispose(){{/code}}.
	211	+1*. In {{code language="none"}}getColumnImage(){{/code}} and {{code language="none"}}getColumnText(){{/code}}, first check whether the element is an instance of {{code language="none"}}TapeData{{/code}} and the column index is 0, and return {{code language="none"}}null{{/code}} otherwise. If the check passes, return the following:\\
	212	+1**. {{code language="none"}}getColumnImage(){{/code}}: {{code language="none"}}presentImage{{/code}} if the index given by the tape data element equals the current value of {{code language="none"}}tape.getHeadPosition(){{/code}}, {{code language="none"}}absentImage{{/code}} otherwise.
	213	+1**. {{code language="none"}}getColumnText(){{/code}}: a {{code language="none"}}String{{/code}} containing the character of the tape data element.
	214	+1. (((
	215	+Add the following lines to {{code language="none"}}createPartControl(){{/code}} in {{code language="none"}}TapeViewPart{{/code}}:
	216	+
	217	+{{code}}
	218	+tableViewer.setContentProvider(new TapeContentProvider());
	219	+tableViewer.setLabelProvider(new TapeLabelProvider(tape));
	220	+tableViewer.setInput(tape);
	221	+{{/code}}
	222	+)))
	223	+
197	197
198	198
199	199	= Creating an Extension Point =

Confluence.Code.ConfluencePageClass[0]

Id

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1		-2982292
	1	+2982295

URL

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1		-https://rtsys.informatik.uni-kiel.de/confluence//wiki/spaces/WS12EclPract/pages/2982292/The Plug-in Architecture of Eclipse
	1	+https://rtsys.informatik.uni-kiel.de/confluence//wiki/spaces/WS12EclPract/pages/2982295/The Plug-in Architecture of Eclipse