net.zer0bandwidth.android.lib.util

Class StringComparator.Base

java.lang.Object

net.zer0bandwidth.android.lib.util.StringComparator.Base

All Implemented Interfaces:

java.util.Comparator<java.lang.String>, StringComparator

Direct Known Subclasses:

JavaStringComparator, LexicalStringComparator

Enclosing interface:

StringComparator

public abstract static class StringComparator.Base
extends java.lang.Object
implements StringComparator

An abstract base class which provides logic that will be common to most, if not all, actual implementations of the interface. The implementation of compare(java.lang.String, java.lang.String) begins by comparing the strings as objects, examining their nullness/emptiness. If that algorithm is already enough to identify the "greater" string, then there is no need for the actual implementation class to do anything further. Otherwise, the implementation class's executeComparison(java.lang.String, java.lang.String) may proceed already knowing that the strings are non-null and non-empty, and that String.equals(java.lang.Object) has already been tried and is not worth trying again.

Since:

zer0bandwidth-net/android 0.2.1 (#56)

Nested Class Summary

Nested classes/interfaces inherited from interface net.zer0bandwidth.android.lib.util.StringComparator

StringComparator.Base

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	EVALUATION_INDETERMINATE Semantic constant not intended as an actual return value; instead, the internal compareAsObjects(java.lang.String, java.lang.String) method will return this when its naïve evaluation of the strings (comparing their nullness and emptiness) isn't enough to resolve the comparison.

Fields inherited from interface net.zer0bandwidth.android.lib.util.StringComparator

EQUAL, S1_IS_GREATER, S2_IS_GREATER

Constructor Summary

Constructors

Constructor and Description
Base()

Method Summary

Modifier and Type	Method and Description
int	compare(java.lang.String s1, java.lang.String s2) Executes compareAsObjects(java.lang.String, java.lang.String) first to determine whether there is already a clear winner, and if not, calls the comparator's more specific executeComparison(java.lang.String, java.lang.String) method.
protected static int	compareAsObjects(java.lang.String s1, java.lang.String s2) Compares the strings as objects — that is, it bases its comparison on the simple question of whether one or both of the strings is null or empty.
protected abstract int	executeComparison(java.lang.String s1, java.lang.String s2) Executes the comparison that is specific to this class.

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

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Field Detail

EVALUATION_INDETERMINATE

protected static final int EVALUATION_INDETERMINATE

Semantic constant not intended as an actual return value; instead, the internal compareAsObjects(java.lang.String, java.lang.String) method will return this when its naïve evaluation of the strings (comparing their nullness and emptiness) isn't enough to resolve the comparison.

See Also:

Constant Field Values

Constructor Detail

Base

public Base()

Method Detail

compareAsObjects

protected static int compareAsObjects(java.lang.String s1,
                                      java.lang.String s2)

Compares the strings as objects — that is, it bases its comparison on the simple question of whether one or both of the strings is null or empty.

• Two references to the same object are trivially equal.
• Null and/or empty strings are equal.
• Non-null strings for which s1.equals(s2) are equal.
• Otherwise, a non-null, non-empty string is "greater than" a null or empty string.

Parameters:

s1 - the first string to compare

s2 - the second string to compare

Returns:

an indication of order or equality

• StringComparator.EQUAL (0) if the strings are equal
• StringComparator.S1_IS_GREATER (1) if the first is "greater"
• StringComparator.S2_IS_GREATER (-1) if the second is "greater"
• EVALUATION_INDETERMINATE if this method's naïve algorithm was not enough to figure out which is greater

executeComparison

protected abstract int executeComparison(java.lang.String s1,
                                         java.lang.String s2)

Executes the comparison that is specific to this class. If the base class's implementation of compare(java.lang.String, java.lang.String) is used as-is, then this method is guaranteed that the strings are non-null, non-empty, and that String.equals(java.lang.Object) has returned false.

Parameters:

s1 - the first string to compare

s2 - the second string to compare

Returns:

an indication of order or equality

• StringComparator.EQUAL (0) if the strings are equal
• StringComparator.S1_IS_GREATER (1) if the first is "greater"
• StringComparator.S2_IS_GREATER (-1) if the second is "greater"

compare

public int compare(java.lang.String s1,
                   java.lang.String s2)

Executes compareAsObjects(java.lang.String, java.lang.String) first to determine whether there is already a clear winner, and if not, calls the comparator's more specific executeComparison(java.lang.String, java.lang.String) method. Implementation classes must override this method if they don't want compareAsObjects to be executed first.

This method does not throw a NullPointerException, as it is specifically designed to handle null values.

Specified by:

compare in interface java.util.Comparator<java.lang.String>

Parameters:

s1 - the first string to compare

s2 - the second string to compare

Returns:

an indication of order or equality

• StringComparator.EQUAL (0) if the strings are equal
• StringComparator.S1_IS_GREATER (1) if the first is "greater"
• StringComparator.S2_IS_GREATER (-1) if the second is "greater"
• EVALUATION_INDETERMINATE if this method's naïve algorithm was not enough to figure out which is greater