private void initTableColumns() {

        addEnabledCol(DataRetentionRule::isEnabled);

        // Rule
        dataGrid.addResizableColumn(
                DataGridUtil.textColumnBuilder((DataRetentionRule row) ->
                                NullSafe.toString(row.getRuleNumber()))
                        .rightAligned()
                        .build(),
                DataGridUtil.headingBuilder("Rule")
                        .rightAligned()
                        .withToolTip("The lower the rule number, the higher priority when matching streams. " +
                                     "A stream's retention will be governed by the matching rule with the " +
                                     "highest priority.")
                        .build(),
                50);

        // Name
        dataGrid.addResizableColumn(
                DataGridUtil.textColumnBuilder(DataRetentionRule::getName)
                        .build(),
                DataGridUtil.headingBuilder("Name")
                        .withToolTip("The name of the rule.")
                        .build(),
                200);

        // Retention
        dataGrid.addResizableColumn(
                DataGridUtil.textColumnBuilder(DataRetentionRule::getAgeString)
                        .build(),
                DataGridUtil.headingBuilder("Retention")
                        .withToolTip("The length of time streams matching this rule will be retained for.")
                        .build(),
                90);

        // Expression
        dataGrid.addResizableColumn(
                DataGridUtil.textColumnBuilder(DataRetentionRule::getAgeString)
                        .build(),
                DataGridUtil.headingBuilder("Expression")
                        .withToolTip("The rule expression used to match streams with.")
                        .build(),
                600);

        addActionButtonColumn(20);
        dataGrid.addEndColumn(new EndColumn<>());
    }
Add the columns to the table.
stroom-core-client/src/main/java/stroom/receive/rules/client/presenter/DataRetentionPolicyListPresenter.java