Package com.tangosol.util.comparator

Class EntryComparator

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.comparator.SafeComparator
com.tangosol.util.comparator.EntryComparator
All Implemented Interfaces:
ExternalizableLite, PortableObject, EntryAwareComparator, QueryMapComparator, Remote.Comparator, Serializable, Comparator
public class EntryComparator extends SafeComparator
Comparator implementation used to compare map entries. Depending on the comparison style this comparator will compare entries' values, entries' keys or, when the provided comparator is an instance of QueryMapComparator, the entries themselves.
Author:
gg 2002.12.14
See Also:

  • Field Details

    • CMP_AUTO

      public static final int CMP_AUTO
      Indicates that this EntryComparator should choose the comparison style based on the underying comparator type.
      See Also:

    • CMP_VALUE

      public static final int CMP_VALUE
      Indicates that this EntryComparator should compare the entries' values.
      See Also:

    • CMP_KEY

      public static final int CMP_KEY
      Indicates that this EntryComparator should compare the entries' keys.
      See Also:

    • CMP_ENTRY

      public static final int CMP_ENTRY
      Indicates that entries that implement QueryMap.Entry interface will be compared using the compareEntries() method.
      See Also:

    • m_nStyle

      protected int m_nStyle
      Comparison style utilized by this EntryComparator. Valid values are any of the CMP_* constants.

  • Constructor Details

    • EntryComparator

      public EntryComparator()
      Default constructor (for ExternalizableLite and PortableObject).

    • EntryComparator

      public EntryComparator(Comparator comparator)
      Construct an EntryComparator to compare entries' values using the provided Comparator object. The EntryComparator will choose the comparison style based on the specified comparator type: if the comparator is an instance of the KeyExtractor, the CMP_KEY style will be assumed; otherwise, the CMP_VALUE style is used.
      Parameters:
      comparator - the comparator to use; if not specified the "natural" comparison of entries' values is used

    • EntryComparator

      public EntryComparator(Comparator comparator, int nStyle)
      Construct an EntryComparator to compare entries using the provided Comparator object according to the specified comparison style. If the style is CMP_AUTO then the comparator type is checked: if the comparator is an instance of the KeyExtractor, the CMP_KEY style will be assumed; otherwise, the CMP_VALUE style is used.
      Parameters:
      comparator - the comparator to use; if not specified the "natural" comparison is used
      nStyle - the comparison style to use; valid values are any of the CMP_* constants

  • Method Details

    • compare

      public int compare(Object o1, Object o2)
      Compares two arguments for order. The arguments must be Map.Entry objects. Depending on the comparison style, this method will pass either the entries' values, keys or the entries themselves to the underlying Comparator.
      Specified by:
      compare in interface Comparator
      Overrides:
      compare in class SafeComparator
      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

    • equals

      public boolean equals(Object o)
      Determine if two EntryComparator objects are equal.
      Specified by:
      equals in interface Comparator
      Overrides:
      equals in class SafeComparator
      Parameters:
      o - the other object
      Returns:
      true if the passed object is equal to this

    • getComparisonStyle

      public int getComparisonStyle()
      Obtain the comparison style value utilized by this EntryComparator. The returned value should be one of the CMP_* constants.
      Returns:
      the comparison style value

    • isCompareValue

      public boolean isCompareValue()
      Check whether or not this EntryComparator uses entries' values to pass for comparison to the underlying Comparator.
      Returns:
      true iff entries' values are used for comparison

    • isCompareKey

      public boolean isCompareKey()
      Check whether or not this EntryComparator uses entries' keys to pass for comparison to the underlying Comparator.
      Returns:
      true iff entries' keys are used for comparison

    • isCompareEntry

      public boolean isCompareEntry()
      Check whether or not this EntryComparator pass entries themselves for comparison to the underlying compareEntries() method.
      Returns:
      true iff entries themselves are used for comparison

    • 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
      Overrides:
      readExternal in class SafeComparator
      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

    • 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
      Overrides:
      writeExternal in class SafeComparator
      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
      Overrides:
      readExternal in class SafeComparator
      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
      Overrides:
      writeExternal in class SafeComparator
      Parameters:
      out - the PofWriter to which to write the object's state
      Throws:
      IOException - if an I/O error occurs