ObjectUtils.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3;
import java.io.IOException;
import java.io.Serializable;
import java.lang.reflect.Array;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.TreeSet;
import java.util.function.Supplier;
import java.util.stream.Stream;
import org.apache.commons.lang3.exception.CloneFailedException;
import org.apache.commons.lang3.function.Suppliers;
import org.apache.commons.lang3.mutable.MutableInt;
import org.apache.commons.lang3.stream.Streams;
import org.apache.commons.lang3.text.StrBuilder;
import org.apache.commons.lang3.time.DurationUtils;
/**
* Operations on {@link Object}.
*
* <p>
* This class tries to handle {@code null} input gracefully.
* An exception will generally not be thrown for a {@code null} input.
* Each method documents its behavior in more detail.
* </p>
*
* <p>#ThreadSafe#</p>
* @since 1.0
*/
//@Immutable
@SuppressWarnings("deprecation") // deprecated class StrBuilder is imported
// because it is part of the signature of deprecated methods
public class ObjectUtils {
/**
* Class used as a null placeholder where {@code null} has another meaning.
*
* <p>
* For example, in a {@link HashMap} the {@link java.util.HashMap#get(Object)} method returns {@code null} if the {@link Map} contains {@code null} or if
* there is no matching key. The {@code null} placeholder can be used to distinguish between these two cases.
* </p>
*
* <p>
* Another example is {@link Hashtable}, where {@code null} cannot be stored.
* </p>
*/
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() {
}
/**
* Ensures singleton after serialization.
*
* @return the singleton value.
*/
private Object readResolve() {
return NULL;
}
}
private static final char AT_SIGN = '@';
/**
* Singleton used as a {@code null} placeholder where {@code null} has another meaning.
*
* <p>
* For example, in a {@link HashMap} the {@link java.util.HashMap#get(Object)} method returns {@code null} if the {@link Map} contains {@code null} or if
* there is no matching key. The {@code null} placeholder can be used to distinguish between these two cases.
* </p>
*
* <p>
* Another example is {@link Hashtable}, where {@code null} cannot be stored.
* </p>
*
* <p>
* This instance is Serializable.
* </p>
*/
public static final Null NULL = new Null();
/**
* Tests if all values in the array are not {@code nulls}.
*
* <p>
* 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.
* </p>
*
* <pre>
* 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
* </pre>
*
* @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) {
return values != null && Stream.of(values).noneMatch(Objects::isNull);
}
/**
* Tests if all values in the given array are {@code null}.
*
* <p>
* If all the values are {@code null} or the array is {@code null} or empty, then {@code true} is returned, otherwise {@code false} is returned.
* </p>
*
* <pre>
* ObjectUtils.allNull(*) = false
* ObjectUtils.allNull(*, null) = false
* ObjectUtils.allNull(null, *) = false
* ObjectUtils.allNull(null, null, *, *) = false
* ObjectUtils.allNull(null) = true
* ObjectUtils.allNull(null, null) = true
* </pre>
*
* @param values the values to test, may be {@code null} or empty.
* @return {@code true} if all values in the array are {@code null}s, {@code false} if there is at least one non-null value in the array.
* @since 3.11
*/
public static boolean allNull(final Object... values) {
return !anyNotNull(values);
}
/**
* Tests if any value in the given array is not {@code null}.
*
* <p>
* 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.
* </p>
*
* <pre>
* 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
* </pre>
*
* @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;
}
/**
* Tests if any value in the given array is {@code null}.
*
* <p>
* If any of the values are {@code null} or the array is {@code null}, then {@code true} is returned, otherwise {@code false} is returned.
* </p>
*
* <pre>
* ObjectUtils.anyNull(*) = false
* ObjectUtils.anyNull(*, *) = false
* ObjectUtils.anyNull(null) = true
* ObjectUtils.anyNull(null, null) = true
* ObjectUtils.anyNull(null, *) = true
* ObjectUtils.anyNull(*, null) = true
* ObjectUtils.anyNull(*, *, null, *) = true
* </pre>
*
* @param values the values to test, may be {@code null} or empty.
* @return {@code true} if there is at least one {@code null} value in the array, {@code false} if all the values are non-null. If the array is {@code null}
* or empty, {@code true} is also returned.
* @since 3.11
*/
public static boolean anyNull(final Object... values) {
return !allNotNull(values);
}
/**
* Clones an object.
*
* @param <T> 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> T clone(final T obj) {
if (obj instanceof Cloneable) {
final Object result;
final Class<? extends Object> objClass = obj.getClass();
if (isArray(obj)) {
final Class<?> componentType = objClass.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 {
result = objClass.getMethod("clone").invoke(obj);
} catch (final ReflectiveOperationException e) {
throw new CloneFailedException("Exception cloning Cloneable type " + objClass.getName(), e);
}
}
return (T) result;
}
return null;
}
/**
* Clones an object if possible.
*
* <p>
* 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.
* </p>
*
* @param <T> 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> 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.
* <p>
* TODO Move to ComparableUtils.
* </p>
*
* @param <T> 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 <T extends Comparable<? super T>> int compare(final T c1, final T c2) {
return compare(c1, c2, false);
}
/**
* Null safe comparison of Comparables.
* <p>
* TODO Move to ComparableUtils.
* </p>
*
* @param <T> 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 <T extends Comparable<? super T>> int compare(final T c1, final T c2, final boolean nullGreater) {
if (c1 == c2) {
return 0;
}
if (c1 == null) {
return nullGreater ? 1 : -1;
}
if (c2 == null) {
return nullGreater ? -1 : 1;
}
return c1.compareTo(c2);
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static boolean MAGIC_FLAG = ObjectUtils.CONST(true);
* </pre>
*
* 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;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static byte MAGIC_BYTE = ObjectUtils.CONST((byte) 127);
* </pre>
*
* 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;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static char MAGIC_CHAR = ObjectUtils.CONST('a');
* </pre>
*
* 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;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static double MAGIC_DOUBLE = ObjectUtils.CONST(1.0);
* </pre>
*
* 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;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static float MAGIC_FLOAT = ObjectUtils.CONST(1.0f);
* </pre>
*
* 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;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static int MAGIC_INT = ObjectUtils.CONST(123);
* </pre>
*
* 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;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static long MAGIC_LONG = ObjectUtils.CONST(123L);
* </pre>
*
* 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;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static short MAGIC_SHORT = ObjectUtils.CONST((short) 123);
* </pre>
*
* 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;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static String MAGIC_STRING = ObjectUtils.CONST("abc");
* </pre>
*
* 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 <T> 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> T CONST(final T v) {
return v;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static byte MAGIC_BYTE = ObjectUtils.CONST_BYTE(127);
* </pre>
*
* 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;
}
/**
* Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,
*
* <pre>
* public final static short MAGIC_SHORT = ObjectUtils.CONST_SHORT(127);
* </pre>
*
* 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;
}
/**
* Returns a default value if the object passed is {@code null}.
*
* <pre>
* ObjectUtils.defaultIfNull(null, null) = null
* ObjectUtils.defaultIfNull(null, "") = ""
* ObjectUtils.defaultIfNull(null, "zz") = "zz"
* ObjectUtils.defaultIfNull("abc", *) = "abc"
* ObjectUtils.defaultIfNull(Boolean.TRUE, *) = Boolean.TRUE
* </pre>
*
* @param <T> the type of the object.
* @param object the {@link Object} to test, may be {@code null}.
* @param defaultValue the default value to return, may be {@code null}.
* @return {@code object} if it is not {@code null}, defaultValue otherwise.
* @see #getIfNull(Object, Object)
* @see #getIfNull(Object, Supplier)
* @deprecated Use {@link #getIfNull(Object, Object)}.
*/
@Deprecated
public static <T> T defaultIfNull(final T object, final T defaultValue) {
return getIfNull(object, defaultValue);
}
// Null-safe equals/hashCode
/**
* Compares two objects for equality, where either one or both
* objects may be {@code null}.
*
* <pre>
* 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
* </pre>
*
* @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) {
return Objects.equals(object1, 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}
* or empty then {@code null} is returned.
*
* <pre>
* ObjectUtils.firstNonNull(null, null) = null
* ObjectUtils.firstNonNull(null, "") = ""
* ObjectUtils.firstNonNull(null, null, "") = ""
* ObjectUtils.firstNonNull(null, "zz") = "zz"
* ObjectUtils.firstNonNull("abc", *) = "abc"
* ObjectUtils.firstNonNull(null, "xyz", *) = "xyz"
* ObjectUtils.firstNonNull(Boolean.TRUE, *) = Boolean.TRUE
* ObjectUtils.firstNonNull() = null
* </pre>
*
* @param <T> the component type of the array.
* @param values the values to test, may be {@code null} or empty.
* @return the first value from {@code values} which is not {@code null},
* or {@code null} if there are no non-null values.
* @since 3.0
*/
@SafeVarargs
public static <T> T firstNonNull(final T... values) {
return Streams.of(values).filter(Objects::nonNull).findFirst().orElse(null);
}
/**
* Delegates to {@link Object#getClass()} using generics.
*
* @param <T> The argument type or null.
* @param object The argument.
* @return The argument's Class or null.
* @since 3.13.0
*/
@SuppressWarnings("unchecked")
public static <T> Class<T> getClass(final T object) {
return object == null ? null : (Class<T>) object.getClass();
}
/**
* Executes the given suppliers in order and returns the first return value where a value other than {@code null} is returned. Once a non-{@code null} value
* is obtained, all following suppliers are not executed anymore. If all the return values are {@code null} or no suppliers are provided then {@code null}
* is returned.
*
* <pre>
* ObjectUtils.firstNonNullLazy(null, () -> null) = null
* ObjectUtils.firstNonNullLazy(() -> null, () -> "") = ""
* ObjectUtils.firstNonNullLazy(() -> "", () -> throw new IllegalStateException()) = ""
* ObjectUtils.firstNonNullLazy(() -> null, () -> "zz) = "zz"
* ObjectUtils.firstNonNullLazy() = null
* </pre>
*
* @param <T> the type of the return values.
* @param suppliers the suppliers returning the values to test. {@code null} values are ignored. Suppliers may return {@code null} or a value of type
* {@code T}.
* @return the first return value from {@code suppliers} which is not {@code null}, or {@code null} if there are no non-null values.
* @since 3.10
*/
@SafeVarargs
public static <T> T getFirstNonNull(final Supplier<T>... suppliers) {
return Streams.of(suppliers).filter(Objects::nonNull).map(Supplier::get).filter(Objects::nonNull).findFirst().orElse(null);
}
/**
* Returns the given {@code object} is it is non-null, otherwise returns the Supplier's {@link Supplier#get()}
* value.
*
* <p>
* The caller responsible for thread-safety and exception handling of default value supplier.
* </p>
*
* <pre>
* ObjectUtils.getIfNull(null, () -> null) = null
* ObjectUtils.getIfNull(null, null) = null
* ObjectUtils.getIfNull(null, () -> "") = ""
* ObjectUtils.getIfNull(null, () -> "zz") = "zz"
* ObjectUtils.getIfNull("abc", *) = "abc"
* ObjectUtils.getIfNull(Boolean.TRUE, *) = Boolean.TRUE
* </pre>
*
* @param <T> the type of the object.
* @param object the {@link Object} to test, may be {@code null}.
* @param defaultSupplier the default value to return, may be {@code null}.
* @return {@code object} if it is not {@code null}, {@code defaultValueSupplier.get()} otherwise.
* @see #getIfNull(Object, Object)
* @since 3.10
*/
public static <T> T getIfNull(final T object, final Supplier<T> defaultSupplier) {
return object != null ? object : Suppliers.get(defaultSupplier);
}
/**
* Returns a default value if the object passed is {@code null}.
*
* <pre>
* ObjectUtils.getIfNull(null, null) = null
* ObjectUtils.getIfNull(null, "") = ""
* ObjectUtils.getIfNull(null, "zz") = "zz"
* ObjectUtils.getIfNull("abc", *) = "abc"
* ObjectUtils.getIfNull(Boolean.TRUE, *) = Boolean.TRUE
* </pre>
*
* @param <T> the type of the object.
* @param object the {@link Object} to test, may be {@code null}.
* @param defaultValue the default value to return, may be {@code null}.
* @return {@code object} if it is not {@code null}, defaultValue otherwise.
* @see #getIfNull(Object, Supplier)
* @since 3.18.0
*/
public static <T> T getIfNull(final T object, final T defaultValue) {
return object != null ? object : defaultValue;
}
/**
* Gets the hash code of an object returning zero when the object is {@code null}.
*
* <pre>
* ObjectUtils.hashCode(null) = 0
* ObjectUtils.hashCode(obj) = obj.hashCode()
* </pre>
*
* @param obj the object to obtain the hash code of, may be {@code null}.
* @return the hash code of the object, or zero if null.
* @since 2.1
* @deprecated this method has been replaced by {@code java.util.Objects.hashCode(Object)} in Java 7 and will be removed in future releases.
*/
@Deprecated
public static int hashCode(final Object obj) {
// hashCode(Object) for performance vs. hashCodeMulti(Object[]), as hash code is often critical
return Objects.hashCode(obj);
}
/**
* Returns the hexadecimal hash code for the given object per {@link Objects#hashCode(Object)}.
* <p>
* Short hand for {@code Integer.toHexString(Objects.hashCode(object))}.
* </p>
*
* @param object object for which the hashCode is to be calculated.
* @return Hash code in hexadecimal format.
* @since 3.13.0
*/
public static String hashCodeHex(final Object object) {
return Integer.toHexString(Objects.hashCode(object));
}
/**
* Gets the hash code for multiple objects.
*
* <p>
* This allows a hash code to be rapidly calculated for a number of objects. The hash code for a single object is the <em>not</em> same as
* {@link #hashCode(Object)}. The hash code for multiple objects is the same as that calculated by an {@link ArrayList} containing the specified objects.
* </p>
*
* <pre>
* ObjectUtils.hashCodeMulti() = 1
* ObjectUtils.hashCodeMulti((Object[]) null) = 1
* ObjectUtils.hashCodeMulti(a) = 31 + a.hashCode()
* ObjectUtils.hashCodeMulti(a,b) = (31 + a.hashCode()) * 31 + b.hashCode()
* ObjectUtils.hashCodeMulti(a,b,c) = ((31 + a.hashCode()) * 31 + b.hashCode()) * 31 + c.hashCode()
* </pre>
*
* @param objects the objects to obtain the hash code of, may be {@code null}.
* @return the hash code of the objects, or zero if null.
* @since 3.0
* @deprecated this method has been replaced by {@code java.util.Objects.hash(Object...)} in Java 7 and will be removed in future releases.
*/
@Deprecated
public static int hashCodeMulti(final Object... objects) {
int hash = 1;
if (objects != null) {
for (final Object object : objects) {
final int tmpHash = Objects.hashCode(object);
hash = hash * 31 + tmpHash;
}
}
return hash;
}
/**
* Returns the hexadecimal hash code for the given object per {@link System#identityHashCode(Object)}.
* <p>
* Short hand for {@code Integer.toHexString(System.identityHashCode(object))}.
* </p>
*
* @param object object for which the hashCode is to be calculated.
* @return Hash code in hexadecimal format.
* @since 3.13.0
*/
public static String identityHashCodeHex(final Object object) {
return Integer.toHexString(System.identityHashCode(object));
}
/**
* Appends the toString that would be produced by {@link Object}
* if a class did not override toString itself. {@code null}
* will throw a NullPointerException for either of the two parameters.
*
* <pre>
* 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")
* </pre>
*
* @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 {
Objects.requireNonNull(object, "object");
appendable.append(object.getClass().getName())
.append(AT_SIGN)
.append(identityHashCodeHex(object));
}
/**
* Gets the toString that would be produced by {@link Object} if a class did not override toString itself. {@code null} will return {@code null}.
*
* <pre>
* ObjectUtils.identityToString(null) = null
* ObjectUtils.identityToString("") = "java.lang.String@1e23"
* ObjectUtils.identityToString(Boolean.TRUE) = "java.lang.Boolean@7fa"
* </pre>
*
* @param object the object to create a toString for, may be {@code null}.
* @return the default toString text, or {@code null} if {@code null} passed in.
*/
public static String identityToString(final Object object) {
if (object == null) {
return null;
}
final String name = object.getClass().getName();
final String hexString = identityHashCodeHex(object);
final StringBuilder builder = new StringBuilder(name.length() + 1 + hexString.length());
// @formatter:off
builder.append(name)
.append(AT_SIGN)
.append(hexString);
// @formatter:on
return builder.toString();
}
/**
* Appends the toString that would be produced by {@link Object}
* if a class did not override toString itself. {@code null}
* will throw a NullPointerException for either of the two parameters.
*
* <pre>
* ObjectUtils.identityToString(builder, "") = builder.append("java.lang.String@1e23")
* ObjectUtils.identityToString(builder, Boolean.TRUE) = builder.append("java.lang.Boolean@7fa")
* ObjectUtils.identityToString(builder, Boolean.TRUE) = builder.append("java.lang.Boolean@7fa")
* </pre>
*
* @param builder the builder to append to.
* @param object the object to create a toString for.
* @since 3.2
* @deprecated as of 3.6, because StrBuilder was moved to commons-text,
* use one of the other {@code identityToString} methods instead.
*/
@Deprecated
public static void identityToString(final StrBuilder builder, final Object object) {
Objects.requireNonNull(object, "object");
final String name = object.getClass().getName();
final String hexString = identityHashCodeHex(object);
builder.ensureCapacity(builder.length() + name.length() + 1 + hexString.length());
builder.append(name)
.append(AT_SIGN)
.append(hexString);
}
/**
* Appends the toString that would be produced by {@link Object}
* if a class did not override toString itself. {@code null}
* will throw a NullPointerException for either of the two parameters.
*
* <pre>
* ObjectUtils.identityToString(buf, "") = buf.append("java.lang.String@1e23")
* ObjectUtils.identityToString(buf, Boolean.TRUE) = buf.append("java.lang.Boolean@7fa")
* ObjectUtils.identityToString(buf, Boolean.TRUE) = buf.append("java.lang.Boolean@7fa")
* </pre>
*
* @param buffer the buffer to append to.
* @param object the object to create a toString for.
* @since 2.4
*/
public static void identityToString(final StringBuffer buffer, final Object object) {
Objects.requireNonNull(object, "object");
final String name = object.getClass().getName();
final String hexString = identityHashCodeHex(object);
buffer.ensureCapacity(buffer.length() + name.length() + 1 + hexString.length());
buffer.append(name)
.append(AT_SIGN)
.append(hexString);
}
/**
* Appends the toString that would be produced by {@link Object}
* if a class did not override toString itself. {@code null}
* will throw a NullPointerException for either of the two parameters.
*
* <pre>
* ObjectUtils.identityToString(builder, "") = builder.append("java.lang.String@1e23")
* ObjectUtils.identityToString(builder, Boolean.TRUE) = builder.append("java.lang.Boolean@7fa")
* ObjectUtils.identityToString(builder, Boolean.TRUE) = builder.append("java.lang.Boolean@7fa")
* </pre>
*
* @param builder the builder to append to.
* @param object the object to create a toString for.
* @since 3.2
*/
public static void identityToString(final StringBuilder builder, final Object object) {
Objects.requireNonNull(object, "object");
final String name = object.getClass().getName();
final String hexString = identityHashCodeHex(object);
builder.ensureCapacity(builder.length() + name.length() + 1 + hexString.length());
builder.append(name)
.append(AT_SIGN)
.append(hexString);
}
/**
* Tests whether the given object is an Object array or a primitive array in a null-safe manner.
*
* <p>
* A {@code null} {@code object} Object will return {@code false}.
* </p>
*
* <pre>
* ObjectUtils.isArray(null) = false
* ObjectUtils.isArray("") = false
* ObjectUtils.isArray("ab") = false
* ObjectUtils.isArray(new int[]{}) = true
* ObjectUtils.isArray(new int[]{1,2,3}) = true
* ObjectUtils.isArray(1234) = false
* </pre>
*
* @param object the object to check, may be {@code null}.
* @return {@code true} if the object is an {@code array}, {@code false} otherwise.
* @since 3.13.0
*/
public static boolean isArray(final Object object) {
return object != null && object.getClass().isArray();
}
/**
* Tests if an Object is empty or null.
* <p>
* The following types are supported:
* </p>
* <ul>
* <li>{@link CharSequence}: Considered empty if its length is zero.</li>
* <li>{@link Array}: Considered empty if its length is zero.</li>
* <li>{@link Collection}: Considered empty if it has zero elements.</li>
* <li>{@link Map}: Considered empty if it has zero key-value mappings.</li>
* <li>{@link Optional}: Considered empty if {@link Optional#isPresent} returns false, regardless of the "emptiness" of the contents.</li>
* </ul>
*
* <pre>
* 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
* ObjectUtils.isEmpty(1234) = false
* ObjectUtils.isEmpty(Optional.of("")) = false
* ObjectUtils.isEmpty(Optional.empty()) = true
* </pre>
*
* @param object the {@link 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 (isArray(object)) {
return Array.getLength(object) == 0;
}
if (object instanceof Collection<?>) {
return ((Collection<?>) object).isEmpty();
}
if (object instanceof Map<?, ?>) {
return ((Map<?, ?>) object).isEmpty();
}
if (object instanceof Optional<?>) {
// TODO Java 11 Use Optional#isEmpty()
return !((Optional<?>) object).isPresent();
}
return false;
}
/**
* Tests if an Object is not empty and not null.
* <p>
* The following types are supported:
* </p>
* <ul>
* <li>{@link CharSequence}: Considered empty if its length is zero.</li>
* <li>{@link Array}: Considered empty if its length is zero.</li>
* <li>{@link Collection}: Considered empty if it has zero elements.</li>
* <li>{@link Map}: Considered empty if it has zero key-value mappings.</li>
* <li>{@link Optional}: Considered empty if {@link Optional#isPresent} returns false, regardless of the "emptiness" of the contents.</li>
* </ul>
*
* <pre>
* 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
* ObjectUtils.isNotEmpty(Optional.of("")) = true
* ObjectUtils.isNotEmpty(Optional.empty()) = false
* </pre>
*
* @param object the {@link 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.
* <p>
* TODO Move to ComparableUtils.
* </p>
*
* @param <T> type of the values processed by this method.
* @param values the set of comparable values, may be null.
* @return
* <ul>
* <li>If any objects are non-null and unequal, the greater object.
* <li>If all objects are non-null and equal, the first.
* <li>If any of the comparables are null, the greater of the non-null objects.
* <li>If all the comparables are null, null is returned.
* </ul>
*/
@SafeVarargs
public static <T extends Comparable<? super T>> 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;
}
/**
* Finds 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 <T> 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> T median(final Comparator<T> comparator, final T... items) {
Validate.notEmpty(items, "null/empty items");
Validate.noNullElements(items);
Objects.requireNonNull(comparator, "comparator");
final TreeSet<T> treeSet = new TreeSet<>(comparator);
Collections.addAll(treeSet, items);
return (T) treeSet.toArray()[(treeSet.size() - 1) / 2];
}
/**
* Finds 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 <T> 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 extends Comparable<? super T>> T median(final T... items) {
Validate.notEmpty(items);
Validate.noNullElements(items);
final TreeSet<T> sort = new TreeSet<>();
Collections.addAll(sort, items);
return (T) sort.toArray()[(sort.size() - 1) / 2];
}
/**
* Null safe comparison of Comparables.
* <p>
* TODO Move to ComparableUtils.
* </p>
*
* @param <T> type of the values processed by this method
* @param values the set of comparable values, may be null
* @return
* <ul>
* <li>If any objects are non-null and unequal, the lesser object.
* <li>If all objects are non-null and equal, the first.
* <li>If any of the comparables are null, the lesser of the non-null objects.
* <li>If all the comparables are null, null is returned.
* </ul>
*/
@SafeVarargs
public static <T extends Comparable<? super T>> 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;
}
/**
* Finds the most frequently occurring item.
*
* @param <T> 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> T mode(final T... items) {
if (ArrayUtils.isNotEmpty(items)) {
final HashMap<T, MutableInt> occurrences = new HashMap<>(items.length);
for (final T t : items) {
ArrayUtils.increment(occurrences, t);
}
T result = null;
int max = 0;
for (final Map.Entry<T, MutableInt> 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}.
*
* <pre>
* 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
* </pre>
*
* @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 !Objects.equals(object1, object2);
}
/**
* Checks that the specified object reference is not {@code null} or empty per {@link #isEmpty(Object)}. Use this
* method for validation, for example:
*
* <pre>
* public Foo(Bar bar) {
* this.bar = Objects.requireNonEmpty(bar);
* }
* </pre>
*
* @param <T> the type of the reference.
* @param obj the object reference to check for nullity.
* @return {@code obj} if not {@code null}.
* @throws NullPointerException if {@code obj} is {@code null}.
* @throws IllegalArgumentException if {@code obj} is empty per {@link #isEmpty(Object)}.
* @see #isEmpty(Object)
* @since 3.12.0
*/
public static <T> T requireNonEmpty(final T obj) {
return requireNonEmpty(obj, "object");
}
/**
* Checks that the specified object reference is not {@code null} or empty per {@link #isEmpty(Object)}. Use this
* method for validation, for example:
*
* <pre>
* public Foo(Bar bar) {
* this.bar = Objects.requireNonEmpty(bar, "bar");
* }
* </pre>
*
* @param <T> the type of the reference.
* @param obj the object reference to check for nullity.
* @param message the exception message.
* @return {@code obj} if not {@code null}.
* @throws NullPointerException if {@code obj} is {@code null}.
* @throws IllegalArgumentException if {@code obj} is empty per {@link #isEmpty(Object)}.
* @see #isEmpty(Object)
* @since 3.12.0
*/
public static <T> T requireNonEmpty(final T obj, final String message) {
// check for null first to give the most precise exception.
Objects.requireNonNull(obj, message);
if (isEmpty(obj)) {
throw new IllegalArgumentException(message);
}
return obj;
}
/**
* Gets the {@code toString()} of an {@link Object} or the empty string ({@code ""}) if the input is {@code null}.
*
* <pre>
* ObjectUtils.toString(null) = ""
* ObjectUtils.toString("") = ""
* ObjectUtils.toString("bat") = "bat"
* ObjectUtils.toString(Boolean.TRUE) = "true"
* </pre>
*
* @param obj the Object to {@code toString()}, may be {@code null}.
* @return the input's {@code toString()}, or {@code ""} if the input is {@code null}.
* @see Objects#toString(Object)
* @see Objects#toString(Object, String)
* @see StringUtils#defaultString(String)
* @see String#valueOf(Object)
* @since 2.0
*/
public static String toString(final Object obj) {
return Objects.toString(obj, StringUtils.EMPTY);
}
/**
* Gets the {@code toString} of an {@link Object} returning
* a specified text if {@code null} input.
*
* <pre>
* ObjectUtils.toString(null, null) = null
* ObjectUtils.toString(null, "null") = "null"
* ObjectUtils.toString("", "null") = ""
* ObjectUtils.toString("bat", "null") = "bat"
* ObjectUtils.toString(Boolean.TRUE, "null") = "true"
* </pre>
*
* @param obj the Object to {@code toString}, may be null.
* @param nullStr the String to return if {@code null} input, may be null.
* @return the passed in Object's toString, or {@code nullStr} if {@code null} input.
* @see Objects#toString(Object)
* @see Objects#toString(Object, String)
* @see StringUtils#defaultString(String,String)
* @see String#valueOf(Object)
* @since 2.0
* @deprecated this method has been replaced by {@code java.util.Objects.toString(Object, String)} in Java 7 and
* will be removed in future releases.
*/
@Deprecated
public static String toString(final Object obj, final String nullStr) {
return Objects.toString(obj, nullStr);
}
/**
* Gets the {@code toString} of an {@link Supplier}'s {@link Supplier#get()} returning
* a specified text if {@code null} input.
*
* <pre>
* ObjectUtils.toString(() -> obj, () -> expensive())
* </pre>
* <pre>
* ObjectUtils.toString(() -> null, () -> expensive()) = result of expensive()
* ObjectUtils.toString(() -> null, () -> expensive()) = result of expensive()
* ObjectUtils.toString(() -> "", () -> expensive()) = ""
* ObjectUtils.toString(() -> "bat", () -> expensive()) = "bat"
* ObjectUtils.toString(() -> Boolean.TRUE, () -> expensive()) = "true"
* </pre>
*
* @param obj the Object to {@code toString}, may be null.
* @param supplier the Supplier of String used on {@code null} input, may be null.
* @return the passed in Object's toString, or {@code nullStr} if {@code null} input.
* @since 3.14.0
*/
public static String toString(final Supplier<Object> obj, final Supplier<String> supplier) {
return obj == null ? Suppliers.get(supplier) : toString(obj.get(), supplier);
}
/**
* Gets the {@code toString} of an {@link Object} returning
* a specified text if {@code null} input.
*
* <pre>
* ObjectUtils.toString(obj, () -> expensive())
* </pre>
* <pre>
* ObjectUtils.toString(null, () -> expensive()) = result of expensive()
* ObjectUtils.toString(null, () -> expensive()) = result of expensive()
* ObjectUtils.toString("", () -> expensive()) = ""
* ObjectUtils.toString("bat", () -> expensive()) = "bat"
* ObjectUtils.toString(Boolean.TRUE, () -> expensive()) = "true"
* </pre>
*
* @param <T> the obj type (used to provide better source compatibility in 3.14.0).
* @param obj the Object to {@code toString}, may be null.
* @param supplier the Supplier of String used on {@code null} input, may be null.
* @return the passed in Object's toString, or {@code nullStr} if {@code null} input.
* @since 3.11
*/
public static <T> String toString(final T obj, final Supplier<String> supplier) {
return obj == null ? Suppliers.get(supplier) : obj.toString();
}
/**
* Calls {@link Object#wait(long, int)} for the given Duration.
*
* @param obj The receiver of the wait call.
* @param duration How long to wait.
* @throws IllegalArgumentException if the timeout duration is negative.
* @throws IllegalMonitorStateException if the current thread is not the owner of the {@code obj}'s monitor.
* @throws InterruptedException if any thread interrupted the current thread before or while the current thread was
* waiting for a notification. The <em>interrupted status</em> of the current thread is cleared when this
* exception is thrown.
* @see Object#wait(long, int)
* @since 3.12.0
*/
public static void wait(final Object obj, final Duration duration) throws InterruptedException {
DurationUtils.accept(obj::wait, DurationUtils.zeroIfNull(duration));
}
/**
* {@link 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");}.
*
* <p>
* This constructor is public to permit tools that require a JavaBean instance to operate.
* </p>
*
* @deprecated TODO Make private in 4.0.
*/
@Deprecated
public ObjectUtils() {
// empty
}
}