Class ComparatorChain
- java.lang.Object
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- org.apache.commons.collections.comparators.ComparatorChain
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- All Implemented Interfaces:
java.io.Serializable
,java.util.Comparator
@Deprecated(since="2021-04-30") public class ComparatorChain extends java.lang.Object implements java.util.Comparator, java.io.Serializable
Deprecated.Commons Collections 3 is in maintenance mode. Commons Collections 4 should be used instead.A ComparatorChain is a Comparator that wraps one or more Comparators in sequence. The ComparatorChain calls each Comparator in sequence until either 1) any single Comparator returns a non-zero result (and that result is then returned), or 2) the ComparatorChain is exhausted (and zero is returned). This type of sorting is very similar to multi-column sorting in SQL, and this class allows Java classes to emulate that kind of behaviour when sorting a List.
To further facilitate SQL-like sorting, the order of any single Comparator in the list can be reversed.
Calling a method that adds new Comparators or changes the ascend/descend sort after compare(Object, Object) has been called will result in an UnsupportedOperationException. However, take care to not alter the underlying List of Comparators or the BitSet that defines the sort order.
Instances of ComparatorChain are not synchronized. The class is not thread-safe at construction time, but it is thread-safe to perform multiple comparisons after all the setup operations are complete.
- Since:
- Commons Collections 2.0
- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description ComparatorChain()
Deprecated.Construct a ComparatorChain with no Comparators.ComparatorChain(java.util.Comparator comparator)
Deprecated.Construct a ComparatorChain with a single Comparator, sorting in the forward orderComparatorChain(java.util.Comparator comparator, boolean reverse)
Deprecated.Construct a Comparator chain with a single Comparator, sorting in the given orderComparatorChain(java.util.List list)
Deprecated.Construct a ComparatorChain from the Comparators in the List.ComparatorChain(java.util.List list, java.util.BitSet bits)
Deprecated.Construct a ComparatorChain from the Comparators in the given List.
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description void
addComparator(java.util.Comparator comparator)
Deprecated.Add a Comparator to the end of the chain using the forward sort ordervoid
addComparator(java.util.Comparator comparator, boolean reverse)
Deprecated.Add a Comparator to the end of the chain using the given sort orderint
compare(java.lang.Object o1, java.lang.Object o2)
Deprecated.Perform comparisons on the Objects as per Comparator.compare(o1,o2).boolean
equals(java.lang.Object object)
Deprecated.Returnstrue
iff that Object is is aComparator
whose ordering is known to be equivalent to mine.int
hashCode()
Deprecated.Implement a hash code for this comparator that is consistent withequals
.boolean
isLocked()
Deprecated.Determine if modifications can still be made to the ComparatorChain.void
setComparator(int index, java.util.Comparator comparator)
Deprecated.Replace the Comparator at the given index, maintaining the existing sort order.void
setComparator(int index, java.util.Comparator comparator, boolean reverse)
Deprecated.Replace the Comparator at the given index in the ComparatorChain, using the given sort ordervoid
setForwardSort(int index)
Deprecated.Change the sort order at the given index in the ComparatorChain to a forward sort.void
setReverseSort(int index)
Deprecated.Change the sort order at the given index in the ComparatorChain to a reverse sort.int
size()
Deprecated.Number of Comparators in the current ComparatorChain.
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Constructor Detail
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ComparatorChain
public ComparatorChain()
Deprecated.Construct a ComparatorChain with no Comparators. You must add at least one Comparator before calling the compare(Object,Object) method, or an UnsupportedOperationException is thrown
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ComparatorChain
public ComparatorChain(java.util.Comparator comparator)
Deprecated.Construct a ComparatorChain with a single Comparator, sorting in the forward order- Parameters:
comparator
- First comparator in the Comparator chain
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ComparatorChain
public ComparatorChain(java.util.Comparator comparator, boolean reverse)
Deprecated.Construct a Comparator chain with a single Comparator, sorting in the given order- Parameters:
comparator
- First Comparator in the ComparatorChainreverse
- false = forward sort; true = reverse sort
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ComparatorChain
public ComparatorChain(java.util.List list)
Deprecated.Construct a ComparatorChain from the Comparators in the List. All Comparators will default to the forward sort order.- Parameters:
list
- List of Comparators- See Also:
ComparatorChain(List,BitSet)
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ComparatorChain
public ComparatorChain(java.util.List list, java.util.BitSet bits)
Deprecated.Construct a ComparatorChain from the Comparators in the given List. The sort order of each column will be drawn from the given BitSet. When determining the sort order for Comparator at index i in the List, the ComparatorChain will call BitSet.get(i). If that method returns false, the forward sort order is used; a return value of true indicates reverse sort order.- Parameters:
list
- List of Comparators. NOTE: This constructor does not perform a defensive copy of the listbits
- Sort order for each Comparator. Extra bits are ignored, unless extra Comparators are added by another method.
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Method Detail
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addComparator
public void addComparator(java.util.Comparator comparator)
Deprecated.Add a Comparator to the end of the chain using the forward sort order- Parameters:
comparator
- Comparator with the forward sort order
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addComparator
public void addComparator(java.util.Comparator comparator, boolean reverse)
Deprecated.Add a Comparator to the end of the chain using the given sort order- Parameters:
comparator
- Comparator to add to the end of the chainreverse
- false = forward sort order; true = reverse sort order
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setComparator
public void setComparator(int index, java.util.Comparator comparator) throws java.lang.IndexOutOfBoundsException
Deprecated.Replace the Comparator at the given index, maintaining the existing sort order.- Parameters:
index
- index of the Comparator to replacecomparator
- Comparator to place at the given index- Throws:
java.lang.IndexOutOfBoundsException
- if index < 0 or index >= size()
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setComparator
public void setComparator(int index, java.util.Comparator comparator, boolean reverse)
Deprecated.Replace the Comparator at the given index in the ComparatorChain, using the given sort order- Parameters:
index
- index of the Comparator to replacecomparator
- Comparator to setreverse
- false = forward sort order; true = reverse sort order
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setForwardSort
public void setForwardSort(int index)
Deprecated.Change the sort order at the given index in the ComparatorChain to a forward sort.- Parameters:
index
- Index of the ComparatorChain
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setReverseSort
public void setReverseSort(int index)
Deprecated.Change the sort order at the given index in the ComparatorChain to a reverse sort.- Parameters:
index
- Index of the ComparatorChain
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size
public int size()
Deprecated.Number of Comparators in the current ComparatorChain.- Returns:
- Comparator count
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isLocked
public boolean isLocked()
Deprecated.Determine if modifications can still be made to the ComparatorChain. ComparatorChains cannot be modified once they have performed a comparison.- Returns:
- true = ComparatorChain cannot be modified; false = ComparatorChain can still be modified.
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compare
public int compare(java.lang.Object o1, java.lang.Object o2) throws java.lang.UnsupportedOperationException
Deprecated.Perform comparisons on the Objects as per Comparator.compare(o1,o2).- Specified by:
compare
in interfacejava.util.Comparator
- Parameters:
o1
- the first object to compareo2
- the second object to compare- Returns:
- -1, 0, or 1
- Throws:
java.lang.UnsupportedOperationException
- if the ComparatorChain does not contain at least one Comparator
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hashCode
public int hashCode()
Deprecated.Implement a hash code for this comparator that is consistent withequals
.- Overrides:
hashCode
in classjava.lang.Object
- Returns:
- a suitable hash code
- Since:
- Commons Collections 3.0
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equals
public boolean equals(java.lang.Object object)
Deprecated.Returnstrue
iff that Object is is aComparator
whose ordering is known to be equivalent to mine.This implementation returns
true
iffobject.
equalsgetClass()
this.getClass()
, and the underlying comparators and order bits are equal. Subclasses may want to override this behavior to remain consistent with theComparator.equals(Object)
contract.- Specified by:
equals
in interfacejava.util.Comparator
- Overrides:
equals
in classjava.lang.Object
- Parameters:
object
- the object to compare with- Returns:
- true if equal
- Since:
- Commons Collections 3.0
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