/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
package net.sourceforge.phpdt.internal.corext.template;

import net.sourceforge.phpdt.internal.corext.Assert;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;


/**
 * A typical text based document template context.
 */
public abstract class DocumentTemplateContext extends TemplateContext {

  /** The text of the document. */
  private final IDocument fDocument;
  /** The completion offset. */
  private final int fCompletionOffset;
  /** The completion length. */
  private final int fCompletionLength;

  /**
   * Creates a document template context.
   */
  protected DocumentTemplateContext(ContextType type, IDocument document,
    int completionOffset, int completionLength)
  {
    super(type);
		
    Assert.isNotNull(document);
    Assert.isTrue(completionOffset >= 0 && completionOffset <= document.getLength());
    Assert.isTrue(completionLength >= 0);
		
    fDocument= document;
    fCompletionOffset= completionOffset;
    fCompletionLength= completionLength;
  }
	
  public IDocument getDocument() {
    return fDocument;	
  }
	
  /**
   * Returns the completion offset within the string of the context.
   */
  public int getCompletionOffset() {
    return fCompletionOffset;	
  }
	
  /**
   * Returns the completion length within the string of the context.
   */
  public int getCompletionLength() {
    return fCompletionLength;
  }
	
  /**
   * Returns the keyword which triggered template insertion.
   */
  public String getKey() {
    int offset= getStart();
    int length= getEnd() - offset;
    try {
      return fDocument.get(offset, length);
    } catch (BadLocationException e) {
      return ""; //$NON-NLS-1$	
    }
  }

  /**
   * Returns the beginning offset of the keyword.
   */
  public int getStart() {
    return fCompletionOffset;		
  }
	
  /**
   * Returns the end offset of the keyword.
   */
  public int getEnd() {
    return fCompletionOffset + fCompletionLength;
  }
		
}