它是如何工作的filterMatchMode从PrimeFaces DataTable

Question

Primefaces Datatable允许您使用属性filterMatchMode配置用于列的过滤类型。

尽管如此，如果您使用LazyDataModel，您必须实现您自己的搜索方法，该方法根本不接收该属性。这个特性只对普通的数据模型有用吗?

Answer 1

目前LazyDataModel开箱即用不支持此特性，但是您仍然可以相对轻松地使用它。blemasle在primefaces论坛上发布了相应的补丁，不幸的是仍然没有来自开发人员的响应。

如果你想使用非代码侵入式的解决方案，你可以试试我的。

过滤器约束通过以下方式获得:

 /**
 * @param tableSearchExpr expression, starting from the view root,
 *        which identifies the datatable to retrieve information from
 * @return map, containing pairs of {@code <filtered field id, match mode>}.
 *         Filtered field id is evaluated from the 'filterBy' 
 *         attribute of the column in the following way:
 *         #{item.name} -> name
 *         #{item.category.name} -> category.name
 */
public Map<String, FilterMatchMode> getFiltersMatchMode(String tableSearchExpr) {
    FacesContext context = FacesContext.getCurrentInstance();
    Object component = context.getViewRoot().findComponent(tableSearchExpr);
    if (null == component) {
        throw new IllegalArgumentException(
                    "No component found for search expression: " 
                            + tableSearchExpr);
    }
    if (!(component instanceof DataTable)) {
        throw new IllegalArgumentException(
                    "Component is not a DataTable: " + tableSearchExpr);
    }
    DataTable table = (DataTable) component;
    Map<String, FilterMatchMode> constraints = 
            new HashMap<String, FilterMatchMode>(table.getColumns().size());
    for (UIColumn column : table.getColumns()) {
        ValueExpression filterExpression = 
                  column.getValueExpression("filterBy");
        if (null != filterExpression) {
            String filterExpressionString = filterExpression.
                                                   getExpressionString();
            //evaluating filtered field id
            String filteredField = filterExpressionString.substring(
                    filterExpressionString.indexOf('.') + 1,
                    filterExpressionString.indexOf('}'));
            FilterMatchMode matchMode = 
                  FilterMatchMode.fromUiParam(column.getFilterMatchMode());
            constraints.put(filteredField, matchMode);
        }
    }
    return constraints;
}

其中FilterMatchMode为:

public enum FilterMatchMode {
STARTS_WITH("startsWith"), ENDS_WITH("endsWith"), 
CONTAINS("contains"), EXACT("exact");
/**
 * Value of p:column's filterMatchMode attribute 
 *     which corresponds to this math mode
 */
private final String uiParam;
FilterMatchMode(String uiParam) {
    this.uiParam = uiParam;
}
/**
 * @param uiParam value of p:column's filterMatchMode attribute
 * @return MatchMode which corresponds to given UI parameter
 * @throws IllegalArgumentException if no MatchMode 
 *          is corresponding to given UI parameter
 */
public static FilterMatchMode fromUiParam(String uiParam) {
    for (FilterMatchMode matchMode : values()) {
        if (matchMode.uiParam.equals(uiParam)) {
            return matchMode;
        }
    }
    throw new IllegalArgumentException("No MatchMode found for " + uiParam);
}
}