com.tangosol.util.comparator
Class ChainedComparator

java.lang.Object
  com.tangosol.util.Base
      com.tangosol.util.comparator.ChainedComparator

All Implemented Interfaces:

ExternalizableLite, PortableObject, EntryAwareComparator, QueryMapComparator, Serializable, Comparator

public class ChainedComparator
extends Base
implements Comparator, QueryMapComparator, EntryAwareComparator, Serializable, ExternalizableLite, PortableObject

Composite comparator implementation based on a collection of comparators. The comparators in the array assumed to be sorted according to their priorities; only in a case when the n-th comparator cannot determine the order of the passed objects:

   aComparator[n].compare(o1, o2) == 0
 

the (n+1)-th comparator will be applied to calculate the value.

Author:

gg 2002.11.14

Field Summary

protected Comparator[]

m_aComparator The Comparator array.

Constructor Summary

ChainedComparator()
Default constructor (for ExternalizableLite and PortableObject).

ChainedComparator(Comparator[] aComparator)
Construct a ChainedComparator.

Method Summary

int	compare(Object o1, Object o2) Compares its two arguments for order.
int	compareEntries(QueryMap.Entry entry1, QueryMap.Entry entry2) Compare two entries based on the rules specified by Comparator.
boolean	equals(Object o) Determine if two ChainedComparator objects are equal.
Comparator[]	getComparators() Obtain the underlying Comparator array.
int	hashCode() Return the hash code for this comparator.
boolean	isKeyComparator() Specifies whether this comparator expects to compare keys or values.
void	readExternal(DataInput in) Restore the contents of this object by loading the object's state from the passed DataInput object.
void	readExternal(PofReader in) Restore the contents of a user type instance by reading its state using the specified PofReader object.
String	toString() Return a human-readable description for this ChainedComparator.
void	writeExternal(DataOutput out) Save the contents of this object by storing the object's state into the passed DataOutput object.
void	writeExternal(PofWriter out) Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Field Detail

m_aComparator

protected Comparator[] m_aComparator

The Comparator array.

Constructor Detail

ChainedComparator

public ChainedComparator()

Default constructor (for ExternalizableLite and PortableObject).

ChainedComparator

public ChainedComparator(Comparator[] aComparator)

Construct a ChainedComparator.

Parameters:

aComparator - the comparator array

Method Detail

compare

public int compare(Object o1,
                   Object o2)

Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

Specified by:

compare in interface Comparator

Parameters:

o1 - the first object to be compared

o2 - the second object to be compared

Returns:

a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second

Throws:

ClassCastException - if the arguments' types prevent them from being compared by this Comparator.

compareEntries

public int compareEntries(QueryMap.Entry entry1,
                          QueryMap.Entry entry2)

Compare two entries based on the rules specified by Comparator.

This implementation simply passes on this invocation to the wrapped Comparator objects if they too implement this interface, or invokes their default compare method passing the values extracted from the passed entries.

Specified by:

compareEntries in interface QueryMapComparator

Parameters:

entry1 - the first entry to compare values from; read-only

entry2 - the second entry to compare values from; read-only

Returns:

a negative integer, zero, or a positive integer as the first entry denotes a value that is is less than, equal to, or greater than the value denoted by the second entry

isKeyComparator

public boolean isKeyComparator()

Specifies whether this comparator expects to compare keys or values.

Specified by:

isKeyComparator in interface EntryAwareComparator

Returns:

true iff all the underlying comparators implement the EntryAwareComparator interface and all isKeyComparator() calls return true

toString

public String toString()

Return a human-readable description for this ChainedComparator.

Returns:

a String description of the ChainedComparator

equals

public boolean equals(Object o)

Determine if two ChainedComparator objects are equal.

Specified by:

equals in interface Comparator

Parameters:

o - the other comparator

Returns:

true if the passed object is equal to this ChainedComparator

hashCode

public int hashCode()

Return the hash code for this comparator.

Returns:

the hash code value for this comparator

getComparators

public Comparator[] getComparators()

Obtain the underlying Comparator array.

Returns:

the Comparator array

readExternal

public void readExternal(DataInput in)
                  throws IOException

Restore the contents of this object by loading the object's state from the passed DataInput object.

Specified by:

readExternal in interface ExternalizableLite

Parameters:

in - the DataInput stream to read data from in order to restore the state of this object

Throws:

IOException - if an I/O exception occurs

NotActiveException - if the object is not in its initial state, and therefore cannot be deserialized into

writeExternal

public void writeExternal(DataOutput out)
                   throws IOException

Save the contents of this object by storing the object's state into the passed DataOutput object.

Specified by:

writeExternal in interface ExternalizableLite

Parameters:

out - the DataOutput stream to write the state of this object to

Throws:

IOException - if an I/O exception occurs

readExternal

public void readExternal(PofReader in)
                  throws IOException

Restore the contents of a user type instance by reading its state using the specified PofReader object.

Specified by:

readExternal in interface PortableObject

Parameters:

in - the PofReader from which to read the object's state

Throws:

IOException - if an I/O error occurs

writeExternal

public void writeExternal(PofWriter out)
                   throws IOException

Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Specified by:

writeExternal in interface PortableObject

Parameters:

out - the PofWriter to which to write the object's state

Throws:

IOException - if an I/O error occurs