How to query geodatabase objects

static ICursor getRestaurants(ITable table)throws Exception{
    // Create the query filter.
    IQueryFilter queryFilter = new QueryFilter();
    // Select the fields to be returned - the name and address of the businesses.
    queryFilter.setSubFields("NAME, ADDRESS");
    // Set the filter to return only restaurants.
    queryFilter.setWhereClause("TYPE = 'Restaurant'");
    // Use the PostfixClause to alphabetically order the set by name.
    IQueryFilterDefinition queryFilterDef = (IQueryFilterDefinition)queryFilter;
    queryFilterDef.setPostfixClause("ORDER BY NAME");
    ICursor cursor = table.ITable_search(queryFilter, true);
    return cursor;
}

static IFeatureCursor getStreetsInEnvelope(IFeatureClass featureClass)throws
    Exception{
    // Create the envelope and define its position.
    IEnvelope envelope = new Envelope();
    envelope.putCoords( - 84.4078, 33.7787,  - 84.3856, 33.7997);
    // Create the spatial filter and set its spatial constraints.
    ISpatialFilter spatialFilter = new SpatialFilter();
    spatialFilter.setGeometryByRef(envelope);
    spatialFilter.setGeometryField(featureClass.getShapeFieldName());
    spatialFilter.setSpatialRel(esriSpatialRelEnum.esriSpatialRelIntersects);
    // Set the attribute constraints and subfields.
    // We want to exclude ramps, highways and interstates.
    spatialFilter.setWhereClause("NAME <> 'Ramp' AND PRE_TYPE NOT IN ('Hwy', 'I')");
    spatialFilter.setSubFields("NAME, TYPE");
    // Execute the query.
    IFeatureCursor featureCursor = featureClass.search(spatialFilter, true);
    return featureCursor;
}

// For example, tables = "customers"
// subFields = "NAME, ADDRESS"
// whereClause = "ADDRESS LIKE '%CENTER%'"
public ICursor useQueryDef(IFeatureWorkspace featureWorkspace, String tables, String
    subFields, String whereClause)throws Exception{
    // Create the query definition.
    IQueryDef queryDef = featureWorkspace.createQueryDef();
    // Provide a list of table(s) to join.
    queryDef.setTables(tables);
    // Declare the subfields to retrieve.
    queryDef.setSubFields(subFields);
    // Assign a where clause to filter the results.
    queryDef.setWhereClause(whereClause);
    // Evaluate queryDef to execute a database query and return a cursor to the application.
    ICursor cursor = queryDef.evaluate();
    return cursor;
}

public ITable createQueryTable(IWorkspace workspace, IQueryDef queryDef, String
    tableName)throws Exception{
    // Create a reference to a TableQueryName object.
    IQueryName2 queryName2 = new TableQueryName();
    queryName2.setPrimaryKey("");
    // Specify the query definition.
    queryName2.setQueryDef(queryDef);
    // Get a name object for the workspace.
    IDataset dataset = (IDataset)workspace;
    IWorkspaceName workspaceName = (IWorkspaceName)dataset.getFullName();
    // Cast the TableQueryName object to the IDatasetName interface and open it.
    IDatasetName datasetName = (IDatasetName)queryName2;
    datasetName.setWorkspaceNameByRef(workspaceName);
    datasetName.setName(tableName);
    IName name = (IName)datasetName;
    // Open the name object and get a reference to a table object.
    ITable table = (ITable)name.open();
    return table;
}

static boolean isPredicateSupported(IWorkspace workspace, int predicate)throws
    Exception{
    // Cast to the ISQLSyntax interface and get the supportedPredicates value.
    ISQLSyntax sqlSyntax = (ISQLSyntax)workspace;
    int supportedPredicates = sqlSyntax.getSupportedPredicates();
    //use bitwise arithmetic to check for support.
    int predicateValue = predicate;
    int supportedValue = predicateValue & supportedPredicates;
    boolean isSupported = supportedValue > 0;
    return isSupported;
}

static String functionNameForWorkspace(IWorkspace workspace, int sqlFunctionName)
    throws Exception{
    // Cast to the ISQLSyntax interface and get the correct function name.
    ISQLSyntax sqlSyntax = (ISQLSyntax)workspace;
    String functionName = sqlSyntax.getFunctionName(sqlFunctionName);
    // If functionName is null, the function is not supported and an exception should be thrown.
    if (functionName == null){
        throw new Exception("SQL Function Not Supported.");
    }
    return functionName;
}