com.datastax.util.lang.ObjectUtils Maven / Gradle / Ivy
package com.datastax.util.lang;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import java.util.Map;
public abstract class ObjectUtils {
private static final int INITIAL_HASH = 7;
private static final int MULTIPLIER = 31;
private static final String EMPTY_STRING = "";
private static final String NULL_STRING = "null";
private static final String ARRAY_START = "{";
private static final String ARRAY_END = "}";
private static final String EMPTY_ARRAY = ARRAY_START + ARRAY_END;
private static final String ARRAY_ELEMENT_SEPARATOR = ", ";
/**
* Return whether the given throwable is a checked exception:
* that is, neither a RuntimeException nor an Error.
* @param ex the throwable to check
* @return whether the throwable is a checked exception
* @see java.lang.Exception
* @see java.lang.RuntimeException
* @see java.lang.Error
*/
public static boolean isCheckedException(Throwable ex) {
return !(ex instanceof RuntimeException || ex instanceof Error);
}
/**
* Check whether the given exception is compatible with the specified
* exception types, as declared in a throws clause.
* @param ex the exception to check
* @param declaredExceptions the exception types declared in the throws clause
* @return whether the given exception is compatible
*/
public static boolean isCompatibleWithThrowsClause(Throwable ex, Class... declaredExceptions) {
if (!isCheckedException(ex)) {
return true;
}
if (declaredExceptions != null) {
for (Class declaredException : declaredExceptions) {
if (declaredException.isInstance(ex)) {
return true;
}
}
}
return false;
}
/**
* Determine whether the given object is an array:
* either an Object array or a primitive array.
* @param obj the object to check
*/
public static boolean isArray(Object obj) {
return (obj != null && obj.getClass().isArray());
}
/**
* Determine whether the given array is empty:
* i.e. {@code null} or of zero length.
* @param array the array to check
* @see #isEmpty(Object)
*/
public static boolean isEmpty(Object[] array) {
return (array == null || array.length == 0);
}
/**
* Determine whether the given object is empty.
* This method supports the following object types.
*
* - {@code Array}: considered empty if its length is zero
* - {@link CharSequence}: considered empty if its length is zero
* - {@link Collection}: delegates to {@link Collection#isEmpty()}
* - {@link Map}: delegates to {@link Map#isEmpty()}
*
* If the given object is non-null and not one of the aforementioned
* supported types, this method returns {@code false}.
* @param obj the object to check
* @return {@code true} if the object is {@code null} or empty
* @since 4.2
* @see ObjectUtils#isEmpty(Object[])
*/
@SuppressWarnings("rawtypes")
public static boolean isEmpty(Object obj) {
if (obj == null) {
return true;
}
if (obj.getClass().isArray()) {
return Array.getLength(obj) == 0;
}
if (obj instanceof CharSequence) {
return ((CharSequence) obj).length() == 0;
}
if (obj instanceof Collection) {
return ((Collection) obj).isEmpty();
}
if (obj instanceof Map) {
return ((Map) obj).isEmpty();
}
// else
return false;
}
/**
* Check whether the given array contains the given element.
* @param array the array to check (may be {@code null},
* in which case the return value will always be {@code false})
* @param element the element to check for
* @return whether the element has been found in the given array
*/
public static boolean containsElement(Object[] array, Object element) {
if (array == null) {
return false;
}
for (Object arrayEle : array) {
if (nullSafeEquals(arrayEle, element)) {
return true;
}
}
return false;
}
/**
* Check whether the given array of enum constants contains a constant with the given name,
* ignoring case when determining a match.
* @param enumValues the enum values to check, typically the product of a call to MyEnum.values()
* @param constant the constant name to find (must not be null or empty string)
* @return whether the constant has been found in the given array
*/
public static boolean containsConstant(Enum[] enumValues, String constant) {
return containsConstant(enumValues, constant, false);
}
/**
* Check whether the given array of enum constants contains a constant with the given name.
* @param enumValues the enum values to check, typically the product of a call to MyEnum.values()
* @param constant the constant name to find (must not be null or empty string)
* @param caseSensitive whether case is significant in determining a match
* @return whether the constant has been found in the given array
*/
public static boolean containsConstant(Enum[] enumValues, String constant, boolean caseSensitive) {
for (Enum candidate : enumValues) {
if (caseSensitive ?
candidate.toString().equals(constant) :
candidate.toString().equalsIgnoreCase(constant)) {
return true;
}
}
return false;
}
/**
* Case insensitive alternative to {@link Enum#valueOf(Class, String)}.
* @param the concrete Enum type
* @param enumValues the array of all Enum constants in question, usually per Enum.values()
* @param constant the constant to get the enum value of
* @throws IllegalArgumentException if the given constant is not found in the given array
* of enum values. Use {@link #containsConstant(Enum[], String)} as a guard to avoid this exception.
*/
public static > E caseInsensitiveValueOf(E[] enumValues, String constant) {
for (E candidate : enumValues) {
if (candidate.toString().equalsIgnoreCase(constant)) {
return candidate;
}
}
throw new IllegalArgumentException(
String.format("constant [%s] does not exist in enum type %s",
constant, enumValues.getClass().getComponentType().getName()));
}
/**
* Append the given object to the given array, returning a new array
* consisting of the input array contents plus the given object.
* @param array the array to append to (can be {@code null})
* @param obj the object to append
* @return the new array (of the same component type; never {@code null})
*/
public static A[] addObjectToArray(A[] array, O obj) {
Class compType = Object.class;
if (array != null) {
compType = array.getClass().getComponentType();
}
else if (obj != null) {
compType = obj.getClass();
}
int newArrLength = (array != null ? array.length + 1 : 1);
@SuppressWarnings("unchecked")
A[] newArr = (A[]) Array.newInstance(compType, newArrLength);
if (array != null) {
System.arraycopy(array, 0, newArr, 0, array.length);
}
newArr[newArr.length - 1] = obj;
return newArr;
}
/**
* Convert the given array (which may be a primitive array) to an
* object array (if necessary of primitive wrapper objects).
* A {@code null} source value will be converted to an
* empty Object array.
* @param source the (potentially primitive) array
* @return the corresponding object array (never {@code null})
* @throws IllegalArgumentException if the parameter is not an array
*/
public static Object[] toObjectArray(Object source) {
if (source instanceof Object[]) {
return (Object[]) source;
}
if (source == null) {
return new Object[0];
}
if (!source.getClass().isArray()) {
throw new IllegalArgumentException("Source is not an array: " + source);
}
int length = Array.getLength(source);
if (length == 0) {
return new Object[0];
}
Class wrapperType = Array.get(source, 0).getClass();
Object[] newArray = (Object[]) Array.newInstance(wrapperType, length);
for (int i = 0; i < length; i++) {
newArray[i] = Array.get(source, i);
}
return newArray;
}
//---------------------------------------------------------------------
// Convenience methods for content-based equality/hash-code handling
//---------------------------------------------------------------------
/**
* Determine if the given objects are equal, returning {@code true}
* if both are {@code null} or {@code false} if only one is
* {@code null}.
*
Compares arrays with {@code Arrays.equals}, performing an equality
* check based on the array elements rather than the array reference.
* @param o1 first Object to compare
* @param o2 second Object to compare
* @return whether the given objects are equal
* @see java.util.Arrays#equals
*/
public static boolean nullSafeEquals(Object o1, Object o2) {
if (o1 == o2) {
return true;
}
if (o1 == null || o2 == null) {
return false;
}
if (o1.equals(o2)) {
return true;
}
if (o1.getClass().isArray() && o2.getClass().isArray()) {
if (o1 instanceof Object[] && o2 instanceof Object[]) {
return Arrays.equals((Object[]) o1, (Object[]) o2);
}
if (o1 instanceof boolean[] && o2 instanceof boolean[]) {
return Arrays.equals((boolean[]) o1, (boolean[]) o2);
}
if (o1 instanceof byte[] && o2 instanceof byte[]) {
return Arrays.equals((byte[]) o1, (byte[]) o2);
}
if (o1 instanceof char[] && o2 instanceof char[]) {
return Arrays.equals((char[]) o1, (char[]) o2);
}
if (o1 instanceof double[] && o2 instanceof double[]) {
return Arrays.equals((double[]) o1, (double[]) o2);
}
if (o1 instanceof float[] && o2 instanceof float[]) {
return Arrays.equals((float[]) o1, (float[]) o2);
}
if (o1 instanceof int[] && o2 instanceof int[]) {
return Arrays.equals((int[]) o1, (int[]) o2);
}
if (o1 instanceof long[] && o2 instanceof long[]) {
return Arrays.equals((long[]) o1, (long[]) o2);
}
if (o1 instanceof short[] && o2 instanceof short[]) {
return Arrays.equals((short[]) o1, (short[]) o2);
}
}
return false;
}
/**
* Return as hash code for the given object; typically the value of
* {@code Object#hashCode()}}. If the object is an array,
* this method will delegate to any of the {@code nullSafeHashCode}
* methods for arrays in this class. If the object is {@code null},
* this method returns 0.
* @see #nullSafeHashCode(Object[])
* @see #nullSafeHashCode(boolean[])
* @see #nullSafeHashCode(byte[])
* @see #nullSafeHashCode(char[])
* @see #nullSafeHashCode(double[])
* @see #nullSafeHashCode(float[])
* @see #nullSafeHashCode(int[])
* @see #nullSafeHashCode(long[])
* @see #nullSafeHashCode(short[])
*/
public static int nullSafeHashCode(Object obj) {
if (obj == null) {
return 0;
}
if (obj.getClass().isArray()) {
if (obj instanceof Object[]) {
return nullSafeHashCode((Object[]) obj);
}
if (obj instanceof boolean[]) {
return nullSafeHashCode((boolean[]) obj);
}
if (obj instanceof byte[]) {
return nullSafeHashCode((byte[]) obj);
}
if (obj instanceof char[]) {
return nullSafeHashCode((char[]) obj);
}
if (obj instanceof double[]) {
return nullSafeHashCode((double[]) obj);
}
if (obj instanceof float[]) {
return nullSafeHashCode((float[]) obj);
}
if (obj instanceof int[]) {
return nullSafeHashCode((int[]) obj);
}
if (obj instanceof long[]) {
return nullSafeHashCode((long[]) obj);
}
if (obj instanceof short[]) {
return nullSafeHashCode((short[]) obj);
}
}
return obj.hashCode();
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(Object[] array) {
if (array == null) {
return 0;
}
int hash = INITIAL_HASH;
for (Object element : array) {
hash = MULTIPLIER * hash + nullSafeHashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(boolean[] array) {
if (array == null) {
return 0;
}
int hash = INITIAL_HASH;
for (boolean element : array) {
hash = MULTIPLIER * hash + hashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(byte[] array) {
if (array == null) {
return 0;
}
int hash = INITIAL_HASH;
for (byte element : array) {
hash = MULTIPLIER * hash + element;
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(char[] array) {
if (array == null) {
return 0;
}
int hash = INITIAL_HASH;
for (char element : array) {
hash = MULTIPLIER * hash + element;
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(double[] array) {
if (array == null) {
return 0;
}
int hash = INITIAL_HASH;
for (double element : array) {
hash = MULTIPLIER * hash + hashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(float[] array) {
if (array == null) {
return 0;
}
int hash = INITIAL_HASH;
for (float element : array) {
hash = MULTIPLIER * hash + hashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(int[] array) {
if (array == null) {
return 0;
}
int hash = INITIAL_HASH;
for (int element : array) {
hash = MULTIPLIER * hash + element;
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(long[] array) {
if (array == null) {
return 0;
}
int hash = INITIAL_HASH;
for (long element : array) {
hash = MULTIPLIER * hash + hashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(short[] array) {
if (array == null) {
return 0;
}
int hash = INITIAL_HASH;
for (short element : array) {
hash = MULTIPLIER * hash + element;
}
return hash;
}
/**
* Return the same value as {@link Boolean#hashCode()}}.
* @see Boolean#hashCode()
*/
public static int hashCode(boolean bool) {
return (bool ? 1231 : 1237);
}
/**
* Return the same value as {@link Double#hashCode()}}.
* @see Double#hashCode()
*/
public static int hashCode(double dbl) {
return hashCode(Double.doubleToLongBits(dbl));
}
/**
* Return the same value as {@link Float#hashCode()}}.
* @see Float#hashCode()
*/
public static int hashCode(float flt) {
return Float.floatToIntBits(flt);
}
/**
* Return the same value as {@link Long#hashCode()}}.
* @see Long#hashCode()
*/
public static int hashCode(long lng) {
return (int) (lng ^ (lng >>> 32));
}
//---------------------------------------------------------------------
// Convenience methods for toString output
//---------------------------------------------------------------------
/**
* Return a String representation of an object's overall identity.
* @param obj the object (may be {@code null})
* @return the object's identity as String representation,
* or an empty String if the object was {@code null}
*/
public static String identityToString(Object obj) {
if (obj == null) {
return EMPTY_STRING;
}
return obj.getClass().getName() + "@" + getIdentityHexString(obj);
}
/**
* Return a hex String form of an object's identity hash code.
* @param obj the object
* @return the object's identity code in hex notation
*/
public static String getIdentityHexString(Object obj) {
return Integer.toHexString(System.identityHashCode(obj));
}
/**
* Return a content-based String representation if {@code obj} is
* not {@code null}; otherwise returns an empty String.
*
Differs from {@link #nullSafeToString(Object)} in that it returns
* an empty String rather than "null" for a {@code null} value.
* @param obj the object to build a display String for
* @return a display String representation of {@code obj}
* @see #nullSafeToString(Object)
*/
public static String getDisplayString(Object obj) {
if (obj == null) {
return EMPTY_STRING;
}
return nullSafeToString(obj);
}
/**
* Determine the class name for the given object.
*
Returns {@code "null"} if {@code obj} is {@code null}.
* @param obj the object to introspect (may be {@code null})
* @return the corresponding class name
*/
public static String nullSafeClassName(Object obj) {
return (obj != null ? obj.getClass().getName() : NULL_STRING);
}
/**
* Return a String representation of the specified Object.
*
Builds a String representation of the contents in case of an array.
* Returns {@code "null"} if {@code obj} is {@code null}.
* @param obj the object to build a String representation for
* @return a String representation of {@code obj}
*/
public static String nullSafeToString(Object obj) {
if (obj == null) {
return NULL_STRING;
}
if (obj instanceof String) {
return (String) obj;
}
if (obj instanceof Object[]) {
return nullSafeToString((Object[]) obj);
}
if (obj instanceof boolean[]) {
return nullSafeToString((boolean[]) obj);
}
if (obj instanceof byte[]) {
return nullSafeToString((byte[]) obj);
}
if (obj instanceof char[]) {
return nullSafeToString((char[]) obj);
}
if (obj instanceof double[]) {
return nullSafeToString((double[]) obj);
}
if (obj instanceof float[]) {
return nullSafeToString((float[]) obj);
}
if (obj instanceof int[]) {
return nullSafeToString((int[]) obj);
}
if (obj instanceof long[]) {
return nullSafeToString((long[]) obj);
}
if (obj instanceof short[]) {
return nullSafeToString((short[]) obj);
}
String str = obj.toString();
return (str != null ? str : EMPTY_STRING);
}
/**
* Return a String representation of the contents of the specified array.
*
The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space). Returns
* {@code "null"} if {@code array} is {@code null}.
* @param array the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(Object[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
if (i == 0) {
sb.append(ARRAY_START);
}
else {
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(String.valueOf(array[i]));
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space). Returns
* {@code "null"} if {@code array} is {@code null}.
* @param array the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(boolean[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
if (i == 0) {
sb.append(ARRAY_START);
}
else {
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space). Returns
* {@code "null"} if {@code array} is {@code null}.
* @param array the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(byte[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
if (i == 0) {
sb.append(ARRAY_START);
}
else {
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space). Returns
* {@code "null"} if {@code array} is {@code null}.
* @param array the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(char[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
if (i == 0) {
sb.append(ARRAY_START);
}
else {
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append("'").append(array[i]).append("'");
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space). Returns
* {@code "null"} if {@code array} is {@code null}.
* @param array the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(double[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
if (i == 0) {
sb.append(ARRAY_START);
}
else {
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space). Returns
* {@code "null"} if {@code array} is {@code null}.
* @param array the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(float[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
if (i == 0) {
sb.append(ARRAY_START);
}
else {
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space). Returns
* {@code "null"} if {@code array} is {@code null}.
* @param array the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(int[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
if (i == 0) {
sb.append(ARRAY_START);
}
else {
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space). Returns
* {@code "null"} if {@code array} is {@code null}.
* @param array the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(long[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
if (i == 0) {
sb.append(ARRAY_START);
}
else {
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space). Returns
* {@code "null"} if {@code array} is {@code null}.
* @param array the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(short[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++) {
if (i == 0) {
sb.append(ARRAY_START);
}
else {
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
}