org.zkoss.zul
Class FieldComparator

java.lang.Object
  org.zkoss.zul.FieldComparator

All Implemented Interfaces:

java.io.Serializable, java.util.Comparator

public class FieldComparator
extends java.lang.Object
implements java.util.Comparator, java.io.Serializable

Based on the the given field names to compare the field value of the object that is passed in compare(java.lang.Object, java.lang.Object) method.

The field names accept compound "a.b.c" expression. It also accept multiple field names that you can give expression in the form of e.g. "name, age, salary" and this comparator will compare in that sequence.

Since:

3.6.0

Author:

henrichen

See Also:

Serialized Form

Constructor Summary

FieldComparator(java.lang.String orderBy, boolean ascending)
Compares with the fields per the given "ORDER BY" clause.

FieldComparator(java.lang.String orderBy, boolean ascending, boolean nullAsMax)
Compares with the fields per the given "ORDER BY" clause.

Method Summary

int	compare(java.lang.Object o1, java.lang.Object o2)
java.lang.String	getOrderBy() Returns the order-by clause.
java.lang.String	getRawOrderBy() Returns the original order-by claused passed to the constructor.
boolean	isAscending() Returns whether the sorting is ascending.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Comparator

equals

Constructor Detail

FieldComparator

public FieldComparator(java.lang.String orderBy,
                       boolean ascending)

Compares with the fields per the given "ORDER BY" clause.

Note: It assumes null as minimum value. If not, use FieldComparator(String, boolean, boolean) instead.

Parameters:

orderBy - the "ORDER BY" clause to be compared upon for the given object in compare(java.lang.Object, java.lang.Object).

ascending - whether to sort as ascending (or descending).

FieldComparator

public FieldComparator(java.lang.String orderBy,
                       boolean ascending,
                       boolean nullAsMax)

Compares with the fields per the given "ORDER BY" clause.

Parameters:

orderBy - the "ORDER BY" clause to be compared upon for the given object in compare(java.lang.Object, java.lang.Object).

ascending - whether to sort as ascending (or descending).

nullAsMax - whether to consider null as the maximum value. If false, null is considered as the minimum value.

Method Detail

compare

public int compare(java.lang.Object o1,
                   java.lang.Object o2)

Specified by:

compare in interface java.util.Comparator

getOrderBy

public java.lang.String getOrderBy()

Returns the order-by clause. Notice that is the parsed result, such as name=category ASC. For the original format, please use getRawOrderBy().

getRawOrderBy

public java.lang.String getRawOrderBy()

Returns the original order-by claused passed to the constructor. It is usually the field's name, such as category, or a concatenation of field names, such as category.name.

Notice that, with the field's name, you could retrieve the value by use of Fields.getByCompound(java.lang.Object, java.lang.String).

Since:

5.0.6

isAscending

public boolean isAscending()

Returns whether the sorting is ascending.

Since:

5.0.6