From 45b32d3a9c9695af12083dfd91dd2b3f4c2912df Mon Sep 17 00:00:00 2001 From: Gary Gregory Date: Tue, 23 Jun 2020 15:10:54 -0400 Subject: [PATCH] Sort members. --- .../org/apache/commons/lang3/ObjectUtils.java | 1518 ++++++++--------- 1 file changed, 759 insertions(+), 759 deletions(-) diff --git a/src/main/java/org/apache/commons/lang3/ObjectUtils.java b/src/main/java/org/apache/commons/lang3/ObjectUtils.java index 940dcd808..f1e5fa2a9 100644 --- a/src/main/java/org/apache/commons/lang3/ObjectUtils.java +++ b/src/main/java/org/apache/commons/lang3/ObjectUtils.java @@ -48,6 +48,46 @@ import org.apache.commons.lang3.text.StrBuilder; // because it is part of the signature of deprecated methods public class ObjectUtils { + // Null + //----------------------------------------------------------------------- + /** + *

Class used as a null placeholder where {@code null} + * has another meaning.

+ * + *

For example, in a {@code HashMap} the + * {@link java.util.HashMap#get(java.lang.Object)} method returns + * {@code null} if the {@code Map} contains {@code null} or if there is + * no matching key. The {@code Null} placeholder can be used to distinguish + * between these two cases.

+ * + *

Another example is {@code Hashtable}, where {@code null} + * cannot be stored.

+ */ + public static class Null implements Serializable { + /** + * Required for serialization support. Declare serialization compatibility with Commons Lang 1.0 + * + * @see java.io.Serializable + */ + private static final long serialVersionUID = 7092611880189329093L; + + /** + * Restricted constructor - singleton. + */ + Null() { + super(); + } + + /** + *

Ensure singleton.

+ * + * @return the singleton value + */ + private Object readResolve() { + return NULL; + } + } + private static final char AT_SIGN = '@'; /** @@ -68,90 +108,421 @@ public class ObjectUtils { public static final Null NULL = new Null(); /** - *

{@code ObjectUtils} instances should NOT be constructed in - * standard programming. Instead, the static methods on the class should - * be used, such as {@code ObjectUtils.defaultIfNull("a","b");}.

+ * Checks if all values in the array are not {@code nulls}. * - *

This constructor is public to permit tools that require a JavaBean - * instance to operate.

+ *

+ * If any value is {@code null} or the array is {@code null} then + * {@code false} is returned. If all elements in array are not + * {@code null} or the array is empty (contains no elements) {@code true} + * is returned. + *

+ * + * 
+     * ObjectUtils.allNotNull(*)             = true
+     * ObjectUtils.allNotNull(*, *)          = true
+     * ObjectUtils.allNotNull(null)          = false
+     * ObjectUtils.allNotNull(null, null)    = false
+     * ObjectUtils.allNotNull(null, *)       = false
+     * ObjectUtils.allNotNull(*, null)       = false
+     * ObjectUtils.allNotNull(*, *, null, *) = false
+     *
+ * + * @param values the values to test, may be {@code null} or empty + * @return {@code false} if there is at least one {@code null} value in the array or the array is {@code null}, + * {@code true} if all values in the array are not {@code null}s or array contains no elements. + * @since 3.5 */ - public ObjectUtils() { - super(); + public static boolean allNotNull(final Object... values) { + if (values == null) { + return false; + } + + for (final Object val : values) { + if (val == null) { + return false; + } + } + + return true; } - // Empty checks + /** + * Checks if any value in the given array is not {@code null}. + * + *

+ * If all the values are {@code null} or the array is {@code null} + * or empty then {@code false} is returned. Otherwise {@code true} is returned. + *

+ * + * 
+     * ObjectUtils.anyNotNull(*)                = true
+     * ObjectUtils.anyNotNull(*, null)          = true
+     * ObjectUtils.anyNotNull(null, *)          = true
+     * ObjectUtils.anyNotNull(null, null, *, *) = true
+     * ObjectUtils.anyNotNull(null)             = false
+     * ObjectUtils.anyNotNull(null, null)       = false
+     *
+ * + * @param values the values to test, may be {@code null} or empty + * @return {@code true} if there is at least one non-null value in the array, + * {@code false} if all values in the array are {@code null}s. + * If the array is {@code null} or empty {@code false} is also returned. + * @since 3.5 + */ + public static boolean anyNotNull(final Object... values) { + return firstNonNull(values) != null; + } + + // cloning //----------------------------------------------------------------------- /** - *

Checks if an Object is empty or null.

+ *

Clone an object.

* - * The following types are supported: - * - * - * 
-     * ObjectUtils.isEmpty(null)             = true
-     * ObjectUtils.isEmpty("")               = true
-     * ObjectUtils.isEmpty("ab")             = false
-     * ObjectUtils.isEmpty(new int[]{})      = true
-     * ObjectUtils.isEmpty(new int[]{1,2,3}) = false
-     * ObjectUtils.isEmpty(1234)             = false
-     *
- * - * @param object the {@code Object} to test, may be {@code null} - * @return {@code true} if the object has a supported type and is empty or null, - * {@code false} otherwise - * @since 3.9 + * @param the type of the object + * @param obj the object to clone, null returns null + * @return the clone if the object implements {@link Cloneable} otherwise {@code null} + * @throws CloneFailedException if the object is cloneable and the clone operation fails + * @since 3.0 */ - public static boolean isEmpty(final Object object) { - if (object == null) { - return true; + public static T clone(final T obj) { + if (obj instanceof Cloneable) { + final Object result; + if (obj.getClass().isArray()) { + final Class componentType = obj.getClass().getComponentType(); + if (componentType.isPrimitive()) { + int length = Array.getLength(obj); + result = Array.newInstance(componentType, length); + while (length-- > 0) { + Array.set(result, length, Array.get(obj, length)); + } + } else { + result = ((Object[]) obj).clone(); + } + } else { + try { + final Method clone = obj.getClass().getMethod("clone"); + result = clone.invoke(obj); + } catch (final NoSuchMethodException e) { + throw new CloneFailedException("Cloneable type " + + obj.getClass().getName() + + " has no clone method", e); + } catch (final IllegalAccessException e) { + throw new CloneFailedException("Cannot clone Cloneable type " + + obj.getClass().getName(), e); + } catch (final InvocationTargetException e) { + throw new CloneFailedException("Exception cloning Cloneable type " + + obj.getClass().getName(), e.getCause()); + } + } + @SuppressWarnings("unchecked") // OK because input is of type T + final T checked = (T) result; + return checked; } - if (object instanceof CharSequence) { - return ((CharSequence) object).length() == 0; - } - if (object.getClass().isArray()) { - return Array.getLength(object) == 0; - } - if (object instanceof Collection) { - return ((Collection) object).isEmpty(); - } - if (object instanceof Map) { - return ((Map) object).isEmpty(); - } - return false; + + return null; } /** - *

Checks if an Object is not empty and not null.

+ *

Clone an object if possible.

* - * The following types are supported: - *
    - *
  • {@link CharSequence}: Considered empty if its length is zero.
    • - *
  • {@code Array}: Considered empty if its length is zero.
    • - *
  • {@link Collection}: Considered empty if it has zero elements.
    • - *
  • {@link Map}: Considered empty if it has zero key-value mappings.
    • - *
+ *

This method is similar to {@link #clone(Object)}, but will return the provided + * instance as the return value instead of {@code null} if the instance + * is not cloneable. This is more convenient if the caller uses different + * implementations (e.g. of a service) and some of the implementations do not allow concurrent + * processing or have state. In such cases the implementation can simply provide a proper + * clone implementation and the caller's code does not have to change.

+ * + * @param the type of the object + * @param obj the object to clone, null returns null + * @return the clone if the object implements {@link Cloneable} otherwise the object itself + * @throws CloneFailedException if the object is cloneable and the clone operation fails + * @since 3.0 + */ + public static T cloneIfPossible(final T obj) { + final T clone = clone(obj); + return clone == null ? obj : clone; + } + + /** + *

Null safe comparison of Comparables. + * {@code null} is assumed to be less than a non-{@code null} value.

+ * + * @param type of the values processed by this method + * @param c1 the first comparable, may be null + * @param c2 the second comparable, may be null + * @return a negative value if c1 < c2, zero if c1 = c2 + * and a positive value if c1 > c2 + */ + public static > int compare(final T c1, final T c2) { + return compare(c1, c2, false); + } + + /** + *

Null safe comparison of Comparables.

+ * + * @param type of the values processed by this method + * @param c1 the first comparable, may be null + * @param c2 the second comparable, may be null + * @param nullGreater if true {@code null} is considered greater + * than a non-{@code null} value or if false {@code null} is + * considered less than a Non-{@code null} value + * @return a negative value if c1 < c2, zero if c1 = c2 + * and a positive value if c1 > c2 + * @see java.util.Comparator#compare(Object, Object) + */ + public static > int compare(final T c1, final T c2, final boolean nullGreater) { + if (c1 == c2) { + return 0; + } else if (c1 == null) { + return nullGreater ? 1 : -1; + } else if (c2 == null) { + return nullGreater ? -1 : 1; + } + return c1.compareTo(c2); + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., * * 
-     * ObjectUtils.isNotEmpty(null)             = false
-     * ObjectUtils.isNotEmpty("")               = false
-     * ObjectUtils.isNotEmpty("ab")             = true
-     * ObjectUtils.isNotEmpty(new int[]{})      = false
-     * ObjectUtils.isNotEmpty(new int[]{1,2,3}) = true
-     * ObjectUtils.isNotEmpty(1234)             = true
+     *     public final static boolean MAGIC_FLAG = ObjectUtils.CONST(true);
      *
* - * @param object the {@code Object} to test, may be {@code null} - * @return {@code true} if the object has an unsupported type or is not empty - * and not null, {@code false} otherwise - * @since 3.9 + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the boolean value to return + * @return the boolean v, unchanged + * @since 3.2 */ - public static boolean isNotEmpty(final Object object) { - return !isEmpty(object); + public static boolean CONST(final boolean v) { + return v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static byte MAGIC_BYTE = ObjectUtils.CONST((byte) 127);
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the byte value to return + * @return the byte v, unchanged + * @since 3.2 + */ + public static byte CONST(final byte v) { + return v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static char MAGIC_CHAR = ObjectUtils.CONST('a');
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the char value to return + * @return the char v, unchanged + * @since 3.2 + */ + public static char CONST(final char v) { + return v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static double MAGIC_DOUBLE = ObjectUtils.CONST(1.0);
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the double value to return + * @return the double v, unchanged + * @since 3.2 + */ + public static double CONST(final double v) { + return v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static float MAGIC_FLOAT = ObjectUtils.CONST(1.0f);
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the float value to return + * @return the float v, unchanged + * @since 3.2 + */ + public static float CONST(final float v) { + return v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static int MAGIC_INT = ObjectUtils.CONST(123);
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the int value to return + * @return the int v, unchanged + * @since 3.2 + */ + public static int CONST(final int v) { + return v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static long MAGIC_LONG = ObjectUtils.CONST(123L);
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the long value to return + * @return the long v, unchanged + * @since 3.2 + */ + public static long CONST(final long v) { + return v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static short MAGIC_SHORT = ObjectUtils.CONST((short) 123);
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the short value to return + * @return the short v, unchanged + * @since 3.2 + */ + public static short CONST(final short v) { + return v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static String MAGIC_STRING = ObjectUtils.CONST("abc");
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param the Object type + * @param v the genericized Object value to return (typically a String). + * @return the genericized Object v, unchanged (typically a String). + * @since 3.2 + */ + public static T CONST(final T v) { + return v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static byte MAGIC_BYTE = ObjectUtils.CONST_BYTE(127);
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the byte literal (as an int) value to return + * @throws IllegalArgumentException if the value passed to v + * is larger than a byte, that is, smaller than -128 or + * larger than 127. + * @return the byte v, unchanged + * @since 3.2 + */ + public static byte CONST_BYTE(final int v) { + if (v < Byte.MIN_VALUE || v > Byte.MAX_VALUE) { + throw new IllegalArgumentException("Supplied value must be a valid byte literal between -128 and 127: [" + v + "]"); + } + return (byte) v; + } + + /** + * This method returns the provided value unchanged. + * This can prevent javac from inlining a constant + * field, e.g., + * + * 
+     *     public final static short MAGIC_SHORT = ObjectUtils.CONST_SHORT(127);
+     *
+ * + * This way any jars that refer to this field do not + * have to recompile themselves if the field's value + * changes at some future date. + * + * @param v the short literal (as an int) value to return + * @throws IllegalArgumentException if the value passed to v + * is larger than a short, that is, smaller than -32768 or + * larger than 32767. + * @return the byte v, unchanged + * @since 3.2 + */ + public static short CONST_SHORT(final int v) { + if (v < Short.MIN_VALUE || v > Short.MAX_VALUE) { + throw new IllegalArgumentException("Supplied value must be a valid byte literal between -32768 and 32767: [" + v + "]"); + } + return (short) v; } /** @@ -175,6 +546,40 @@ public class ObjectUtils { return object != null ? object : defaultValue; } + // Null-safe equals/hashCode + //----------------------------------------------------------------------- + /** + *

Compares two objects for equality, where either one or both + * objects may be {@code null}.

+ * + * 
+     * ObjectUtils.equals(null, null)                  = true
+     * ObjectUtils.equals(null, "")                    = false
+     * ObjectUtils.equals("", null)                    = false
+     * ObjectUtils.equals("", "")                      = true
+     * ObjectUtils.equals(Boolean.TRUE, null)          = false
+     * ObjectUtils.equals(Boolean.TRUE, "true")        = false
+     * ObjectUtils.equals(Boolean.TRUE, Boolean.TRUE)  = true
+     * ObjectUtils.equals(Boolean.TRUE, Boolean.FALSE) = false
+     *
+ * + * @param object1 the first object, may be {@code null} + * @param object2 the second object, may be {@code null} + * @return {@code true} if the values of both objects are the same + * @deprecated this method has been replaced by {@code java.util.Objects.equals(Object, Object)} in Java 7 and will + * be removed from future releases. + */ + @Deprecated + public static boolean equals(final Object object1, final Object object2) { + if (object1 == object2) { + return true; + } + if (object1 == null || object2 == null) { + return false; + } + return object1.equals(object2); + } + /** *

Returns the first value in the array which is not {@code null}. * If all the values are {@code null} or the array is {@code null} @@ -277,129 +682,6 @@ public class ObjectUtils { return object != null ? object : defaultSupplier == null ? null : defaultSupplier.get(); } - /** - * Checks if any value in the given array is not {@code null}. - * - *

- * If all the values are {@code null} or the array is {@code null} - * or empty then {@code false} is returned. Otherwise {@code true} is returned. - *

- * - * 
-     * ObjectUtils.anyNotNull(*)                = true
-     * ObjectUtils.anyNotNull(*, null)          = true
-     * ObjectUtils.anyNotNull(null, *)          = true
-     * ObjectUtils.anyNotNull(null, null, *, *) = true
-     * ObjectUtils.anyNotNull(null)             = false
-     * ObjectUtils.anyNotNull(null, null)       = false
-     *
- * - * @param values the values to test, may be {@code null} or empty - * @return {@code true} if there is at least one non-null value in the array, - * {@code false} if all values in the array are {@code null}s. - * If the array is {@code null} or empty {@code false} is also returned. - * @since 3.5 - */ - public static boolean anyNotNull(final Object... values) { - return firstNonNull(values) != null; - } - - /** - * Checks if all values in the array are not {@code nulls}. - * - *

- * If any value is {@code null} or the array is {@code null} then - * {@code false} is returned. If all elements in array are not - * {@code null} or the array is empty (contains no elements) {@code true} - * is returned. - *

- * - * 
-     * ObjectUtils.allNotNull(*)             = true
-     * ObjectUtils.allNotNull(*, *)          = true
-     * ObjectUtils.allNotNull(null)          = false
-     * ObjectUtils.allNotNull(null, null)    = false
-     * ObjectUtils.allNotNull(null, *)       = false
-     * ObjectUtils.allNotNull(*, null)       = false
-     * ObjectUtils.allNotNull(*, *, null, *) = false
-     *
- * - * @param values the values to test, may be {@code null} or empty - * @return {@code false} if there is at least one {@code null} value in the array or the array is {@code null}, - * {@code true} if all values in the array are not {@code null}s or array contains no elements. - * @since 3.5 - */ - public static boolean allNotNull(final Object... values) { - if (values == null) { - return false; - } - - for (final Object val : values) { - if (val == null) { - return false; - } - } - - return true; - } - - // Null-safe equals/hashCode - //----------------------------------------------------------------------- - /** - *

Compares two objects for equality, where either one or both - * objects may be {@code null}.

- * - * 
-     * ObjectUtils.equals(null, null)                  = true
-     * ObjectUtils.equals(null, "")                    = false
-     * ObjectUtils.equals("", null)                    = false
-     * ObjectUtils.equals("", "")                      = true
-     * ObjectUtils.equals(Boolean.TRUE, null)          = false
-     * ObjectUtils.equals(Boolean.TRUE, "true")        = false
-     * ObjectUtils.equals(Boolean.TRUE, Boolean.TRUE)  = true
-     * ObjectUtils.equals(Boolean.TRUE, Boolean.FALSE) = false
-     *
- * - * @param object1 the first object, may be {@code null} - * @param object2 the second object, may be {@code null} - * @return {@code true} if the values of both objects are the same - * @deprecated this method has been replaced by {@code java.util.Objects.equals(Object, Object)} in Java 7 and will - * be removed from future releases. - */ - @Deprecated - public static boolean equals(final Object object1, final Object object2) { - if (object1 == object2) { - return true; - } - if (object1 == null || object2 == null) { - return false; - } - return object1.equals(object2); - } - - /** - *

Compares two objects for inequality, where either one or both - * objects may be {@code null}.

- * - * 
-     * ObjectUtils.notEqual(null, null)                  = false
-     * ObjectUtils.notEqual(null, "")                    = true
-     * ObjectUtils.notEqual("", null)                    = true
-     * ObjectUtils.notEqual("", "")                      = false
-     * ObjectUtils.notEqual(Boolean.TRUE, null)          = true
-     * ObjectUtils.notEqual(Boolean.TRUE, "true")        = true
-     * ObjectUtils.notEqual(Boolean.TRUE, Boolean.TRUE)  = false
-     * ObjectUtils.notEqual(Boolean.TRUE, Boolean.FALSE) = true
-     *
- * - * @param object1 the first object, may be {@code null} - * @param object2 the second object, may be {@code null} - * @return {@code false} if the values of both objects are the same - */ - public static boolean notEqual(final Object object1, final Object object2) { - return !equals(object1, object2); - } - /** *

Gets the hash code of an object returning zero when the * object is {@code null}.

@@ -455,6 +737,29 @@ public class ObjectUtils { return hash; } + /** + *

Appends the toString that would be produced by {@code Object} + * if a class did not override toString itself. {@code null} + * will throw a NullPointerException for either of the two parameters.

+ * + * 
+     * ObjectUtils.identityToString(appendable, "")            = appendable.append("java.lang.String@1e23"
+     * ObjectUtils.identityToString(appendable, Boolean.TRUE)  = appendable.append("java.lang.Boolean@7fa"
+     * ObjectUtils.identityToString(appendable, Boolean.TRUE)  = appendable.append("java.lang.Boolean@7fa")
+     *
+ * + * @param appendable the appendable to append to + * @param object the object to create a toString for + * @throws IOException if an I/O error occurs + * @since 3.2 + */ + public static void identityToString(final Appendable appendable, final Object object) throws IOException { + Validate.notNull(object, "Cannot get the toString of a null object"); + appendable.append(object.getClass().getName()) + .append(AT_SIGN) + .append(Integer.toHexString(System.identityHashCode(object))); + } + // Identity ToString //----------------------------------------------------------------------- /** @@ -488,29 +793,6 @@ public class ObjectUtils { return builder.toString(); } - /** - *

Appends the toString that would be produced by {@code Object} - * if a class did not override toString itself. {@code null} - * will throw a NullPointerException for either of the two parameters.

- * - * 
-     * ObjectUtils.identityToString(appendable, "")            = appendable.append("java.lang.String@1e23"
-     * ObjectUtils.identityToString(appendable, Boolean.TRUE)  = appendable.append("java.lang.Boolean@7fa"
-     * ObjectUtils.identityToString(appendable, Boolean.TRUE)  = appendable.append("java.lang.Boolean@7fa")
-     *
- * - * @param appendable the appendable to append to - * @param object the object to create a toString for - * @throws IOException if an I/O error occurs - * @since 3.2 - */ - public static void identityToString(final Appendable appendable, final Object object) throws IOException { - Validate.notNull(object, "Cannot get the toString of a null object"); - appendable.append(object.getClass().getName()) - .append(AT_SIGN) - .append(Integer.toHexString(System.identityHashCode(object))); - } - /** *

Appends the toString that would be produced by {@code Object} * if a class did not override toString itself. {@code null} @@ -589,6 +871,264 @@ public class ObjectUtils { .append(hexString); } + + // Constants (LANG-816): + /* + These methods ensure constants are not inlined by javac. + For example, typically a developer might declare a constant like so: + + public final static int MAGIC_NUMBER = 5; + + Should a different jar file refer to this, and the MAGIC_NUMBER + is changed a later date (e.g., MAGIC_NUMBER = 6), the different jar + file will need to recompile itself. This is because javac + typically inlines the primitive or String constant directly into + the bytecode, and removes the reference to the MAGIC_NUMBER field. + + To help the other jar (so that it does not need to recompile + when constants are changed) the original developer can declare + their constant using one of the CONST() utility methods, instead: + + public final static int MAGIC_NUMBER = CONST(5); + */ + + + // Empty checks + //----------------------------------------------------------------------- + /** + *

Checks if an Object is empty or null.

+ * + * The following types are supported: + *
    + *
  • {@link CharSequence}: Considered empty if its length is zero.
    • + *
  • {@code Array}: Considered empty if its length is zero.
    • + *
  • {@link Collection}: Considered empty if it has zero elements.
    • + *
  • {@link Map}: Considered empty if it has zero key-value mappings.
    • + *
+ * + * 
+     * ObjectUtils.isEmpty(null)             = true
+     * ObjectUtils.isEmpty("")               = true
+     * ObjectUtils.isEmpty("ab")             = false
+     * ObjectUtils.isEmpty(new int[]{})      = true
+     * ObjectUtils.isEmpty(new int[]{1,2,3}) = false
+     * ObjectUtils.isEmpty(1234)             = false
+     *
+ * + * @param object the {@code Object} to test, may be {@code null} + * @return {@code true} if the object has a supported type and is empty or null, + * {@code false} otherwise + * @since 3.9 + */ + public static boolean isEmpty(final Object object) { + if (object == null) { + return true; + } + if (object instanceof CharSequence) { + return ((CharSequence) object).length() == 0; + } + if (object.getClass().isArray()) { + return Array.getLength(object) == 0; + } + if (object instanceof Collection) { + return ((Collection) object).isEmpty(); + } + if (object instanceof Map) { + return ((Map) object).isEmpty(); + } + return false; + } + + /** + *

Checks if an Object is not empty and not null.

+ * + * The following types are supported: + *
    + *
  • {@link CharSequence}: Considered empty if its length is zero.
    • + *
  • {@code Array}: Considered empty if its length is zero.
    • + *
  • {@link Collection}: Considered empty if it has zero elements.
    • + *
  • {@link Map}: Considered empty if it has zero key-value mappings.
    • + *
+ * + * 
+     * ObjectUtils.isNotEmpty(null)             = false
+     * ObjectUtils.isNotEmpty("")               = false
+     * ObjectUtils.isNotEmpty("ab")             = true
+     * ObjectUtils.isNotEmpty(new int[]{})      = false
+     * ObjectUtils.isNotEmpty(new int[]{1,2,3}) = true
+     * ObjectUtils.isNotEmpty(1234)             = true
+     *
+ * + * @param object the {@code Object} to test, may be {@code null} + * @return {@code true} if the object has an unsupported type or is not empty + * and not null, {@code false} otherwise + * @since 3.9 + */ + public static boolean isNotEmpty(final Object object) { + return !isEmpty(object); + } + + /** + *

Null safe comparison of Comparables.

+ * + * @param type of the values processed by this method + * @param values the set of comparable values, may be null + * @return + *
    + *
  • If any objects are non-null and unequal, the greater object. + *
  • If all objects are non-null and equal, the first. + *
  • If any of the comparables are null, the greater of the non-null objects. + *
  • If all the comparables are null, null is returned. + *
+ */ + @SafeVarargs + public static > T max(final T... values) { + T result = null; + if (values != null) { + for (final T value : values) { + if (compare(value, result, false) > 0) { + result = value; + } + } + } + return result; + } + + /** + * Find the "best guess" middle value among comparables. If there is an even + * number of total values, the lower of the two middle values will be returned. + * @param type of values processed by this method + * @param comparator to use for comparisons + * @param items to compare + * @return T at middle position + * @throws NullPointerException if items or comparator is {@code null} + * @throws IllegalArgumentException if items is empty or contains {@code null} values + * @since 3.0.1 + */ + @SafeVarargs + public static T median(final Comparator comparator, final T... items) { + Validate.notEmpty(items, "null/empty items"); + Validate.noNullElements(items); + Validate.notNull(comparator, "null comparator"); + final TreeSet sort = new TreeSet<>(comparator); + Collections.addAll(sort, items); + @SuppressWarnings("unchecked") //we know all items added were T instances + final + T result = (T) sort.toArray()[(sort.size() - 1) / 2]; + return result; + } + + /** + * Find the "best guess" middle value among comparables. If there is an even + * number of total values, the lower of the two middle values will be returned. + * @param type of values processed by this method + * @param items to compare + * @return T at middle position + * @throws NullPointerException if items is {@code null} + * @throws IllegalArgumentException if items is empty or contains {@code null} values + * @since 3.0.1 + */ + @SafeVarargs + public static > T median(final T... items) { + Validate.notEmpty(items); + Validate.noNullElements(items); + final TreeSet sort = new TreeSet<>(); + Collections.addAll(sort, items); + @SuppressWarnings("unchecked") //we know all items added were T instances + final T result = (T) sort.toArray()[(sort.size() - 1) / 2]; + return result; + } + + // Comparable + //----------------------------------------------------------------------- + /** + *

Null safe comparison of Comparables.

+ * + * @param type of the values processed by this method + * @param values the set of comparable values, may be null + * @return + *
    + *
  • If any objects are non-null and unequal, the lesser object. + *
  • If all objects are non-null and equal, the first. + *
  • If any of the comparables are null, the lesser of the non-null objects. + *
  • If all the comparables are null, null is returned. + *
+ */ + @SafeVarargs + public static > T min(final T... values) { + T result = null; + if (values != null) { + for (final T value : values) { + if (compare(value, result, true) < 0) { + result = value; + } + } + } + return result; + } + + + // Mode + //----------------------------------------------------------------------- + /** + * Find the most frequently occurring item. + * + * @param type of values processed by this method + * @param items to check + * @return most populous T, {@code null} if non-unique or no items supplied + * @since 3.0.1 + */ + @SafeVarargs + public static T mode(final T... items) { + if (ArrayUtils.isNotEmpty(items)) { + final HashMap occurrences = new HashMap<>(items.length); + for (final T t : items) { + final MutableInt count = occurrences.get(t); + if (count == null) { + occurrences.put(t, new MutableInt(1)); + } else { + count.increment(); + } + } + T result = null; + int max = 0; + for (final Map.Entry e : occurrences.entrySet()) { + final int cmp = e.getValue().intValue(); + if (cmp == max) { + result = null; + } else if (cmp > max) { + max = cmp; + result = e.getKey(); + } + } + return result; + } + return null; + } + + /** + *

Compares two objects for inequality, where either one or both + * objects may be {@code null}.

+ * + * 
+     * ObjectUtils.notEqual(null, null)                  = false
+     * ObjectUtils.notEqual(null, "")                    = true
+     * ObjectUtils.notEqual("", null)                    = true
+     * ObjectUtils.notEqual("", "")                      = false
+     * ObjectUtils.notEqual(Boolean.TRUE, null)          = true
+     * ObjectUtils.notEqual(Boolean.TRUE, "true")        = true
+     * ObjectUtils.notEqual(Boolean.TRUE, Boolean.TRUE)  = false
+     * ObjectUtils.notEqual(Boolean.TRUE, Boolean.FALSE) = true
+     *
+ * + * @param object1 the first object, may be {@code null} + * @param object2 the second object, may be {@code null} + * @return {@code false} if the values of both objects are the same + */ + public static boolean notEqual(final Object object1, final Object object2) { + return !equals(object1, object2); + } + // ToString //----------------------------------------------------------------------- /** @@ -642,556 +1182,16 @@ public class ObjectUtils { return obj == null ? nullStr : obj.toString(); } - // Comparable - //----------------------------------------------------------------------- /** - *

Null safe comparison of Comparables.

+ *

{@code ObjectUtils} instances should NOT be constructed in + * standard programming. Instead, the static methods on the class should + * be used, such as {@code ObjectUtils.defaultIfNull("a","b");}.

* - * @param type of the values processed by this method - * @param values the set of comparable values, may be null - * @return - *
    - *
  • If any objects are non-null and unequal, the lesser object. - *
  • If all objects are non-null and equal, the first. - *
  • If any of the comparables are null, the lesser of the non-null objects. - *
  • If all the comparables are null, null is returned. - *
+ *

This constructor is public to permit tools that require a JavaBean + * instance to operate.

*/ - @SafeVarargs - public static > T min(final T... values) { - T result = null; - if (values != null) { - for (final T value : values) { - if (compare(value, result, true) < 0) { - result = value; - } - } - } - return result; - } - - /** - *

Null safe comparison of Comparables.

- * - * @param type of the values processed by this method - * @param values the set of comparable values, may be null - * @return - *
    - *
  • If any objects are non-null and unequal, the greater object. - *
  • If all objects are non-null and equal, the first. - *
  • If any of the comparables are null, the greater of the non-null objects. - *
  • If all the comparables are null, null is returned. - *
- */ - @SafeVarargs - public static > T max(final T... values) { - T result = null; - if (values != null) { - for (final T value : values) { - if (compare(value, result, false) > 0) { - result = value; - } - } - } - return result; - } - - /** - *

Null safe comparison of Comparables. - * {@code null} is assumed to be less than a non-{@code null} value.

- * - * @param type of the values processed by this method - * @param c1 the first comparable, may be null - * @param c2 the second comparable, may be null - * @return a negative value if c1 < c2, zero if c1 = c2 - * and a positive value if c1 > c2 - */ - public static > int compare(final T c1, final T c2) { - return compare(c1, c2, false); - } - - /** - *

Null safe comparison of Comparables.

- * - * @param type of the values processed by this method - * @param c1 the first comparable, may be null - * @param c2 the second comparable, may be null - * @param nullGreater if true {@code null} is considered greater - * than a non-{@code null} value or if false {@code null} is - * considered less than a Non-{@code null} value - * @return a negative value if c1 < c2, zero if c1 = c2 - * and a positive value if c1 > c2 - * @see java.util.Comparator#compare(Object, Object) - */ - public static > int compare(final T c1, final T c2, final boolean nullGreater) { - if (c1 == c2) { - return 0; - } else if (c1 == null) { - return nullGreater ? 1 : -1; - } else if (c2 == null) { - return nullGreater ? -1 : 1; - } - return c1.compareTo(c2); - } - - /** - * Find the "best guess" middle value among comparables. If there is an even - * number of total values, the lower of the two middle values will be returned. - * @param type of values processed by this method - * @param items to compare - * @return T at middle position - * @throws NullPointerException if items is {@code null} - * @throws IllegalArgumentException if items is empty or contains {@code null} values - * @since 3.0.1 - */ - @SafeVarargs - public static > T median(final T... items) { - Validate.notEmpty(items); - Validate.noNullElements(items); - final TreeSet sort = new TreeSet<>(); - Collections.addAll(sort, items); - @SuppressWarnings("unchecked") //we know all items added were T instances - final T result = (T) sort.toArray()[(sort.size() - 1) / 2]; - return result; - } - - /** - * Find the "best guess" middle value among comparables. If there is an even - * number of total values, the lower of the two middle values will be returned. - * @param type of values processed by this method - * @param comparator to use for comparisons - * @param items to compare - * @return T at middle position - * @throws NullPointerException if items or comparator is {@code null} - * @throws IllegalArgumentException if items is empty or contains {@code null} values - * @since 3.0.1 - */ - @SafeVarargs - public static T median(final Comparator comparator, final T... items) { - Validate.notEmpty(items, "null/empty items"); - Validate.noNullElements(items); - Validate.notNull(comparator, "null comparator"); - final TreeSet sort = new TreeSet<>(comparator); - Collections.addAll(sort, items); - @SuppressWarnings("unchecked") //we know all items added were T instances - final - T result = (T) sort.toArray()[(sort.size() - 1) / 2]; - return result; - } - - // Mode - //----------------------------------------------------------------------- - /** - * Find the most frequently occurring item. - * - * @param type of values processed by this method - * @param items to check - * @return most populous T, {@code null} if non-unique or no items supplied - * @since 3.0.1 - */ - @SafeVarargs - public static T mode(final T... items) { - if (ArrayUtils.isNotEmpty(items)) { - final HashMap occurrences = new HashMap<>(items.length); - for (final T t : items) { - final MutableInt count = occurrences.get(t); - if (count == null) { - occurrences.put(t, new MutableInt(1)); - } else { - count.increment(); - } - } - T result = null; - int max = 0; - for (final Map.Entry e : occurrences.entrySet()) { - final int cmp = e.getValue().intValue(); - if (cmp == max) { - result = null; - } else if (cmp > max) { - max = cmp; - result = e.getKey(); - } - } - return result; - } - return null; - } - - // cloning - //----------------------------------------------------------------------- - /** - *

Clone an object.

- * - * @param the type of the object - * @param obj the object to clone, null returns null - * @return the clone if the object implements {@link Cloneable} otherwise {@code null} - * @throws CloneFailedException if the object is cloneable and the clone operation fails - * @since 3.0 - */ - public static T clone(final T obj) { - if (obj instanceof Cloneable) { - final Object result; - if (obj.getClass().isArray()) { - final Class componentType = obj.getClass().getComponentType(); - if (componentType.isPrimitive()) { - int length = Array.getLength(obj); - result = Array.newInstance(componentType, length); - while (length-- > 0) { - Array.set(result, length, Array.get(obj, length)); - } - } else { - result = ((Object[]) obj).clone(); - } - } else { - try { - final Method clone = obj.getClass().getMethod("clone"); - result = clone.invoke(obj); - } catch (final NoSuchMethodException e) { - throw new CloneFailedException("Cloneable type " - + obj.getClass().getName() - + " has no clone method", e); - } catch (final IllegalAccessException e) { - throw new CloneFailedException("Cannot clone Cloneable type " - + obj.getClass().getName(), e); - } catch (final InvocationTargetException e) { - throw new CloneFailedException("Exception cloning Cloneable type " - + obj.getClass().getName(), e.getCause()); - } - } - @SuppressWarnings("unchecked") // OK because input is of type T - final T checked = (T) result; - return checked; - } - - return null; - } - - /** - *

Clone an object if possible.

- * - *

This method is similar to {@link #clone(Object)}, but will return the provided - * instance as the return value instead of {@code null} if the instance - * is not cloneable. This is more convenient if the caller uses different - * implementations (e.g. of a service) and some of the implementations do not allow concurrent - * processing or have state. In such cases the implementation can simply provide a proper - * clone implementation and the caller's code does not have to change.

- * - * @param the type of the object - * @param obj the object to clone, null returns null - * @return the clone if the object implements {@link Cloneable} otherwise the object itself - * @throws CloneFailedException if the object is cloneable and the clone operation fails - * @since 3.0 - */ - public static T cloneIfPossible(final T obj) { - final T clone = clone(obj); - return clone == null ? obj : clone; - } - - // Null - //----------------------------------------------------------------------- - /** - *

Class used as a null placeholder where {@code null} - * has another meaning.

- * - *

For example, in a {@code HashMap} the - * {@link java.util.HashMap#get(java.lang.Object)} method returns - * {@code null} if the {@code Map} contains {@code null} or if there is - * no matching key. The {@code Null} placeholder can be used to distinguish - * between these two cases.

- * - *

Another example is {@code Hashtable}, where {@code null} - * cannot be stored.

- */ - public static class Null implements Serializable { - /** - * Required for serialization support. Declare serialization compatibility with Commons Lang 1.0 - * - * @see java.io.Serializable - */ - private static final long serialVersionUID = 7092611880189329093L; - - /** - * Restricted constructor - singleton. - */ - Null() { - super(); - } - - /** - *

Ensure singleton.

- * - * @return the singleton value - */ - private Object readResolve() { - return NULL; - } - } - - - // Constants (LANG-816): - /* - These methods ensure constants are not inlined by javac. - For example, typically a developer might declare a constant like so: - - public final static int MAGIC_NUMBER = 5; - - Should a different jar file refer to this, and the MAGIC_NUMBER - is changed a later date (e.g., MAGIC_NUMBER = 6), the different jar - file will need to recompile itself. This is because javac - typically inlines the primitive or String constant directly into - the bytecode, and removes the reference to the MAGIC_NUMBER field. - - To help the other jar (so that it does not need to recompile - when constants are changed) the original developer can declare - their constant using one of the CONST() utility methods, instead: - - public final static int MAGIC_NUMBER = CONST(5); - */ - - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static boolean MAGIC_FLAG = ObjectUtils.CONST(true);
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the boolean value to return - * @return the boolean v, unchanged - * @since 3.2 - */ - public static boolean CONST(final boolean v) { - return v; - } - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static byte MAGIC_BYTE = ObjectUtils.CONST((byte) 127);
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the byte value to return - * @return the byte v, unchanged - * @since 3.2 - */ - public static byte CONST(final byte v) { - return v; - } - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static byte MAGIC_BYTE = ObjectUtils.CONST_BYTE(127);
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the byte literal (as an int) value to return - * @throws IllegalArgumentException if the value passed to v - * is larger than a byte, that is, smaller than -128 or - * larger than 127. - * @return the byte v, unchanged - * @since 3.2 - */ - public static byte CONST_BYTE(final int v) { - if (v < Byte.MIN_VALUE || v > Byte.MAX_VALUE) { - throw new IllegalArgumentException("Supplied value must be a valid byte literal between -128 and 127: [" + v + "]"); - } - return (byte) v; - } - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static char MAGIC_CHAR = ObjectUtils.CONST('a');
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the char value to return - * @return the char v, unchanged - * @since 3.2 - */ - public static char CONST(final char v) { - return v; - } - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static short MAGIC_SHORT = ObjectUtils.CONST((short) 123);
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the short value to return - * @return the short v, unchanged - * @since 3.2 - */ - public static short CONST(final short v) { - return v; - } - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static short MAGIC_SHORT = ObjectUtils.CONST_SHORT(127);
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the short literal (as an int) value to return - * @throws IllegalArgumentException if the value passed to v - * is larger than a short, that is, smaller than -32768 or - * larger than 32767. - * @return the byte v, unchanged - * @since 3.2 - */ - public static short CONST_SHORT(final int v) { - if (v < Short.MIN_VALUE || v > Short.MAX_VALUE) { - throw new IllegalArgumentException("Supplied value must be a valid byte literal between -32768 and 32767: [" + v + "]"); - } - return (short) v; - } - - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static int MAGIC_INT = ObjectUtils.CONST(123);
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the int value to return - * @return the int v, unchanged - * @since 3.2 - */ - public static int CONST(final int v) { - return v; - } - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static long MAGIC_LONG = ObjectUtils.CONST(123L);
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the long value to return - * @return the long v, unchanged - * @since 3.2 - */ - public static long CONST(final long v) { - return v; - } - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static float MAGIC_FLOAT = ObjectUtils.CONST(1.0f);
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the float value to return - * @return the float v, unchanged - * @since 3.2 - */ - public static float CONST(final float v) { - return v; - } - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static double MAGIC_DOUBLE = ObjectUtils.CONST(1.0);
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param v the double value to return - * @return the double v, unchanged - * @since 3.2 - */ - public static double CONST(final double v) { - return v; - } - - /** - * This method returns the provided value unchanged. - * This can prevent javac from inlining a constant - * field, e.g., - * - * 
-     *     public final static String MAGIC_STRING = ObjectUtils.CONST("abc");
-     *
- * - * This way any jars that refer to this field do not - * have to recompile themselves if the field's value - * changes at some future date. - * - * @param the Object type - * @param v the genericized Object value to return (typically a String). - * @return the genericized Object v, unchanged (typically a String). - * @since 3.2 - */ - public static T CONST(final T v) { - return v; + public ObjectUtils() { + super(); } }