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/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.custom;


/**
 * Clients may implement the StyledTextContent interface to provide a 
 * custom store for the StyledText widget content. The StyledText widget 
 * interacts with its StyledTextContent in order to access and update 
 * the text that is being displayed and edited in the widget. 
 * A custom content implementation can be set in the widget using the
 * StyledText.setContent API.
 */
public interface StyledTextContent {

/**
 * Called by StyledText to add itself as an Observer to content changes.
 * See TextChangeListener for a description of the listener methods that
 * are called when text changes occur.
 * 

* * @param listener the listener * @exception IllegalArgumentException

    *
  • ERROR_NULL_ARGUMENT when listener is null
  • *
*/ public void addTextChangeListener(TextChangeListener listener); /** * Return the number of characters in the content. *

* * @return the number of characters in the content. */ public int getCharCount(); /** * Return the line at the given line index without delimiters. *

* * @param lineIndex index of the line to return. Does not include * delimiters of preceding lines. Index 0 is the first line of the * content. * @return the line text without delimiters */ public String getLine(int lineIndex); /** * Return the line index at the given character offset. *

* * @param offset offset of the line to return. The first character of the * document is at offset 0. An offset of getLength() is valid and should * answer the number of lines. * @return the line index. The first line is at index 0. If the character * at offset is a delimiter character, answer the line index of the line * that is delimited. * For example, if text = "\r\n\r\n", and delimiter = "\r\n", then: *

    *
  • getLineAtOffset(0) == 0 *
  • getLineAtOffset(1) == 0 *
  • getLineAtOffset(2) == 1 *
  • getLineAtOffset(3) == 1 *
  • getLineAtOffset(4) == 2 *
*/ public int getLineAtOffset(int offset); /** * Return the number of lines. Should answer 1 when no text is specified. * The StyledText widget relies on this behavior for drawing the cursor. *

* * @return the number of lines. For example: *

    *
  • text value ==> getLineCount *
  • null ==> 1 *
  • "" ==> 1 *
  • "a\n" ==> 2 *
  • "\n\n" ==> 3 *
*/ public int getLineCount(); /** * Return the line delimiter that should be used by the StyledText * widget when inserting new lines. New lines entered using key strokes * and paste operations use this line delimiter. * Implementors may use System.getProperty("line.separator") to return * the platform line delimiter. *

* * @return the line delimiter that should be used by the StyledText widget * when inserting new lines. */ public String getLineDelimiter(); /** * Return the character offset of the first character of the given line. *

* NOTE: When there is no text (i.e., no lines), getOffsetAtLine(0) * is a valid call that should return 0. *

* * @param lineIndex index of the line. The first line is at index 0. * @return offset offset of the first character of the line. The first * character of the document is at offset 0. The return value should * include line delimiters. * For example, if text = "\r\ntest\r\n" and delimiter = "\r\n", then: *
    *
  • getOffsetAtLine(0) == 0 *
  • getOffsetAtLine(1) == 2 *
  • getOffsetAtLine(2) == 8 *
*/ public int getOffsetAtLine(int lineIndex); /** * Returns a string representing the content at the given range. *

* * @param start the start offset of the text to return. Offset 0 is the * first character of the document. * @param length the length of the text to return * @return the text at the given range */ public String getTextRange(int start, int length); /** * Remove the specified text changed listener. *

* * @param listener the listener which should no longer be notified * * @exception IllegalArgumentException

    *
  • ERROR_NULL_ARGUMENT when listener is null
  • *
*/ public void removeTextChangeListener(TextChangeListener listener); /** * Replace the text with "newText" starting at position "start" * for a length of "replaceLength". *

* Implementors have to notify the TextChangeListeners that were added * using addTextChangeListener before and after the content * is changed. A TextChangingEvent has to be sent to the * textChanging method before the content is changed and a * TextChangedEvent has to be sent to the textChanged method * after the content has changed. * The text change that occurs after the TextChangingEvent * has been sent has to be consistent with the data provided in the * TextChangingEvent. * This data will be cached by the widget and will be used when the * TextChangedEvent is received. *

* The TextChangingEvent should be set as follows: *

    *
  • event.start = start of the replaced text *
  • event.newText = text that is going to be inserted or empty String * if no text will be inserted *
  • event.replaceCharCount = length of text that is going to be replaced *
  • event.newCharCount = length of text that is going to be inserted *
  • event.replaceLineCount = number of lines that are going to be replaced *
  • event.newLineCount = number of new lines that are going to be inserted *
* NOTE: newLineCount is the number of inserted lines and replaceLineCount * is the number of deleted lines based on the change that occurs visually. * For example: *
    *
  • (replaceText, newText) ==> (replaceLineCount, newLineCount) *
  • ("", "\n") ==> (0, 1) *
  • ("\n\n", "a") ==> (2, 0) *
  • ("a", "\n\n") ==> (0, 2) *
  • ("\n", "") ==> (1, 0) *
*

* * @param start start offset of text to replace, none of the offsets include * delimiters of preceding lines, offset 0 is the first character of the * document * @param replaceLength length of text to replace * @param text text to replace * @see TextChangeListener */ public void replaceTextRange(int start, int replaceLength, String text); /** * Set text to "text". * Implementors have to send a TextChangedEvent to the * textSet method of the TextChangeListeners that were added using * addTextChangeListener. *

* * @param text the new text * @see TextChangeListener */ public void setText(String text); }





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