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require values parameter when generating bit vectors from enums, throwing NullPointerException if omitted; merge check for type eligibility; add E... generateBitVector() variant; alter generateBitVector(Class<E>, EnumSet<E>) to (Class<E>, Iterable<E>) by using |= << instead of + to accumulate values; process only specified values 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1149320 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Matthew Jason Benson 2011-07-21 19:11:47 +00:00
parent 42c7d34dff
commit 37b9565b26
2 changed files with 115 additions and 35 deletions
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92
src/main/java/org/apache/commons/lang3/EnumUtils.java
View File

@ -123,58 +123,86 @@ public static <E extends Enum<E>> E getEnum(Class<E> enumClass, String enumName)
* <p>Do not use this method if you have more than 64 values in your Enum, as this
* would create a value greater than a long can hold.</p>
*
* @param enumClass the class of the enum we are working with, not null
* @param set the set of enum values we want to convert
* @param enumClass the class of the enum we are working with, not {@code null}
* @param values the values we want to convert, not {@code null}
* @param <E> the type of the enumeration
* @return a long whose binary value represents the given set of enum values.
* @throws NullPointerException if {@code enumClass} or {@code values} is {@code null}
* @throws IllegalArgumentException if {@code enumClass} is not an enum class or has more than 64 values
* @since 3.0.1
*/
public static <E extends Enum<E>> long generateBitVector(Class<E> enumClass, EnumSet<E> set) {
if (enumClass == null) {
throw new IllegalArgumentException("EnumClass must be defined.");
}
final E[] constants = enumClass.getEnumConstants();
if (constants != null && constants.length > 64) {
throw new IllegalArgumentException("EnumClass is too big to be stored in a 64-bit value.");
}
public static <E extends Enum<E>> long generateBitVector(Class<E> enumClass, Iterable<E> values) {
checkBitVectorable(enumClass);
Validate.notNull(values);
long total = 0;
if (set != null) {
if (constants != null && constants.length > 0) {
for (E constant : constants) {
if (set.contains(constant)) {
total += Math.pow(2, constant.ordinal());
}
}
}
for (E constant : values) {
total |= (1 << constant.ordinal());
}
return total;
}
/**
* <p>Creates a long bit vector representation of the given array of Enum values.</p>
*
* <p>This generates a value that is usable by {@link EnumUtils#processBitVector}.</p>
*
* <p>Do not use this method if you have more than 64 values in your Enum, as this
* would create a value greater than a long can hold.</p>
*
* @param enumClass the class of the enum we are working with, not {@code null}
* @param values the values we want to convert, not {@code null}
* @param <E> the type of the enumeration
* @return a long whose binary value represents the given set of enum values.
* @throws NullPointerException if {@code enumClass} or {@code values} is {@code null}
* @throws IllegalArgumentException if {@code enumClass} is not an enum class or has more than 64 values
* @since 3.0.1
*/
public static <E extends Enum<E>> long generateBitVector(Class<E> enumClass, E... values) {
Validate.noNullElements(values);
return generateBitVector(enumClass, Arrays.<E> asList(values));
}
/**
* <p>Convert a long value created by {@link EnumUtils#generateBitVector} into the set of
* enum values that it represents.</p>
*
* <p>If you store this value, beware any changes to the enum that would affect ordinal values.</p>
* @param enumClass the class of the enum we are working with, not null
* @param enumClass the class of the enum we are working with, not {@code null}
* @param value the long value representation of a set of enum values
* @param <E> the type of the enumeration
* @return a set of enum values
* @throws NullPointerException if {@code enumClass} is {@code null}
* @throws IllegalArgumentException if {@code enumClass} is not an enum class or has more than 64 values
* @since 3.0.1
*/
public static <E extends Enum<E>> EnumSet<E> processBitVector(Class<E> enumClass, long value) {
if (enumClass == null) {
throw new IllegalArgumentException("EnumClass must be defined.");
}
final E[] constants = enumClass.getEnumConstants();
if (constants != null && constants.length > 64) {
throw new IllegalArgumentException("EnumClass is too big to be stored in a 64-bit value.");
}
final EnumSet results = EnumSet.noneOf(enumClass);
if (constants != null && constants.length > 0) {
for (E constant : constants) {
if ((value & (1 << constant.ordinal())) != 0) {
results.add(constant);
}
final E[] constants = checkBitVectorable(enumClass).getEnumConstants();
final EnumSet<E> results = EnumSet.noneOf(enumClass);
for (E constant : constants) {
if ((value & (1 << constant.ordinal())) != 0) {
results.add(constant);
}
}
return results;
}
/**
* Validate that {@code enumClass} is compatible with representation in a {@code long}.
* @param <E> the type of the enumeration
* @param enumClass to check
* @return {@code enumClass}
* @throws NullPointerException if {@code enumClass} is {@code null}
* @throws IllegalArgumentException if {@code enumClass} is not an enum class or has more than 64 values
* @since 3.0.1
*/
private static <E extends Enum<E>> Class<E> checkBitVectorable(Class<E> enumClass) {
Validate.notNull(enumClass, "EnumClass must be defined.");
final E[] constants = enumClass.getEnumConstants();
Validate.isTrue(constants != null, "%s does not seem to be an Enum type", enumClass);
Validate.isTrue(constants.length <= Long.SIZE, "Cannot store %s %s values in %s bits", constants.length,
enumClass.getSimpleName(), Long.SIZE);
return enumClass;
}
}

58
src/test/java/org/apache/commons/lang3/EnumUtilsTest.java
View File

@ -20,6 +20,7 @@
import static org.junit.Assert.*;
import java.util.ArrayList;
import java.util.EnumSet;
import java.util.List;
import java.util.Map;
@ -89,19 +90,56 @@ public void test_getEnum_nullClass() {
EnumUtils.getEnum((Class<Traffic>) null, "PURPLE");
}
@Test(expected=IllegalArgumentException.class)
@Test(expected=NullPointerException.class)
public void test_generateBitVector_nullClass() {
EnumUtils.generateBitVector(null, EnumSet.of(Traffic.RED));
}
@Test(expected=NullPointerException.class)
public void test_generateBitVector_nullIterable() {
EnumUtils.generateBitVector(null, (Iterable<Traffic>) null);
}
@Test(expected=NullPointerException.class)
public void test_generateBitVector_nullClassWithArray() {
EnumUtils.generateBitVector(null, Traffic.RED);
}
@Test(expected=NullPointerException.class)
public void test_generateBitVector_nullArray() {
EnumUtils.generateBitVector(null, (Traffic[]) null);
}
@Test(expected=IllegalArgumentException.class)
public void test_generateBitVector_longClass() {
EnumUtils.generateBitVector(TooMany.class, EnumSet.of(TooMany.A1));
}
@Test(expected=IllegalArgumentException.class)
public void test_generateBitVector_longClassWithArray() {
EnumUtils.generateBitVector(TooMany.class, TooMany.A1);
}
@SuppressWarnings("unchecked")
@Test(expected=IllegalArgumentException.class)
public void test_generateBitVector_nonEnumClass() {
@SuppressWarnings("rawtypes")
Class rawType = Object.class;
@SuppressWarnings("rawtypes")
List rawList = new ArrayList();
EnumUtils.generateBitVector(rawType, rawList);
}
@SuppressWarnings("unchecked")
@Test(expected=IllegalArgumentException.class)
public void test_generateBitVector_nonEnumClassWithArray() {
@SuppressWarnings("rawtypes")
Class rawType = Object.class;
EnumUtils.generateBitVector(rawType);
}
@Test
public void test_generateBitVector() {
assertEquals(0L, EnumUtils.generateBitVector(Traffic.class, null));
assertEquals(0L, EnumUtils.generateBitVector(Traffic.class, EnumSet.noneOf(Traffic.class)));
assertEquals(1L, EnumUtils.generateBitVector(Traffic.class, EnumSet.of(Traffic.RED)));
assertEquals(2L, EnumUtils.generateBitVector(Traffic.class, EnumSet.of(Traffic.AMBER)));
@ -112,7 +150,21 @@ public void test_generateBitVector() {
assertEquals(7L, EnumUtils.generateBitVector(Traffic.class, EnumSet.of(Traffic.RED, Traffic.AMBER, Traffic.GREEN)));
}
@Test(expected=IllegalArgumentException.class)
@Test
public void test_generateBitVectorFromArray() {
assertEquals(0L, EnumUtils.generateBitVector(Traffic.class));
assertEquals(1L, EnumUtils.generateBitVector(Traffic.class, Traffic.RED));
assertEquals(2L, EnumUtils.generateBitVector(Traffic.class, Traffic.AMBER));
assertEquals(4L, EnumUtils.generateBitVector(Traffic.class, Traffic.GREEN));
assertEquals(3L, EnumUtils.generateBitVector(Traffic.class, Traffic.RED, Traffic.AMBER));
assertEquals(5L, EnumUtils.generateBitVector(Traffic.class, Traffic.RED, Traffic.GREEN));
assertEquals(6L, EnumUtils.generateBitVector(Traffic.class, Traffic.AMBER, Traffic.GREEN));
assertEquals(7L, EnumUtils.generateBitVector(Traffic.class, Traffic.RED, Traffic.AMBER, Traffic.GREEN));
//gracefully handles duplicates:
assertEquals(7L, EnumUtils.generateBitVector(Traffic.class, Traffic.RED, Traffic.AMBER, Traffic.GREEN, Traffic.GREEN));
}
@Test(expected=NullPointerException.class)
public void test_processBitVector_nullClass() {
final Class<Traffic> empty = null;
EnumUtils.processBitVector(empty, 0L);