IPreferencesService service = Platform.getPreferencesService();
        if( null == service ) {
            // Probably not running under Eclipse
            return new ValidationConfiguration();
        }
        
        IProject project = null; // TODO Where can I get this?
        IScopeContext[] contexts = { new ProjectScope( project ) };
        
        String defaultValue = "";
        String patterns = service.getString( I18N_QUALIFIER, VALIDATION_IGNORE_PATTERN_KEY, defaultValue, contexts );
        
        ValidationConfiguration config = new ValidationConfiguration();
        config.setIgnoreString( patterns );
        
        return config;

import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.Logger;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.ProjectScope;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.preferences.IPreferencesService;
import org.eclipse.core.runtime.preferences.IScopeContext;
import org.eclipse.emf.common.util.URI;


public class I18nPreferences {
    
    private final static Logger log = Logger.getLogger( I18nPreferences.class );
    
    private final static String I18N_QUALIFIER = "com.pany.eclipse.i18n_dsl.I18nDsl"; // Name of the prefs file under .settings
    private final static String VALIDATION_IGNORE_PATTERN_KEY = "validation.ignore"; // Key in the prefs file

    /** Get validation configuration for a resource */
    public ValidationConfiguration validationConfiguration( URI uri ) {

        // URI looks like this: 
        // platform:/resource/project/src/.../file.dsl
        log.debug( "Search config for " + uri );
        ValidationConfiguration config = new ValidationConfiguration();

        IPreferencesService service = Platform.getPreferencesService();
        if( null == service ) {
            // Probably not running under Eclipse
            log.debug( "No IPreferencesService" );
            return config;
        }
        
        String s = uri.toString();
        s = StringUtils.substringAfter( s, "platform:/resource/" );
        String projectName = StringUtils.substringBefore( s, "/" );
        log.debug( "Loading preferences for " + projectName );
        
        IWorkspace workspace = ResourcesPlugin.getWorkspace();
        IProject project = (IProject) workspace.getRoot().findMember( projectName );
        if( null == project ) {
            log.debug( "Can't locate project " + projectName + " in workspace" );
            return config;
        }
        
        // Only project specific preferences are considered
        IScopeContext[] contexts = { new ProjectScope( project ) };
        
        String defaultValue = "";
        String patterns = service.getString( I18N_QUALIFIER, VALIDATION_IGNORE_PATTERN_KEY, defaultValue, contexts );
        log.debug( "Found pattern: " + patterns );
        
        config.setIgnoreString( patterns );
        
        return config;
    }
}