Bug 77586 Build Path inclusion filters: filter language must be explained
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/TypeRestrictionEntryDialog.java
doChangeControlPressed();
		}
	}
	
	protected void doChangeControlPressed() {
		IPath pattern= chooseExclusionPattern();
		if (pattern != null) {
			fExclusionPatternDialog.setText(pattern.toString());
		}
	}
	protected void doStatusLineUpdate() {
		checkIfPatternValid();
		updateStatus(fExclusionPatternStatus);
	}		
	
	protected void checkIfPatternValid() {
		String pattern= fExclusionPatternDialog.getText().trim();
		if (pattern.length() == 0) {
			fExclusionPatternStatus.setError(NewWizardMessages.getString("TypeRestrictionEntryDialog.error.empty")); 
			return;
		}
		IPath path= new Path(pattern);
		if (path.isAbsolute() || path.getDevice() != null) {
			fExclusionPatternStatus.setError(NewWizardMessages.getString("TypeRestrictionEntryDialog.error.notrelative")); 
			return;
		}
		if (fExistingPatterns.contains(pattern)) {
			fExclusionPatternStatus.setError(NewWizardMessages.getString("TypeRestrictionEntryDialog.error.exists")); 
			return;
		}