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/*
 * Copyright (C) 2014 The Guava Authors
 *
 * Licensed 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
 *
 * http://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 jersey.repackaged.com.google.common.base;

import static jersey.repackaged.com.google.common.base.Preconditions.checkNotNull;

import jersey.repackaged.com.google.common.annotations.GwtCompatible;

import javax.annotation.Nullable;

/**
 * Helper functions that operate on any {@code Object}, and are not already provided in
 * {@link java.util.Objects}.
 *
 * 

See the Guava User Guide on writing * {@code Object} methods with {@code MoreObjects}. * * @author Laurence Gonsalves * @since 18.0 (since 2.0 as {@code Objects}) */ @GwtCompatible public final class MoreObjects { /** * Returns the first of two given parameters that is not {@code null}, if either is, or otherwise * throws a {@link NullPointerException}. * *

Note: if {@code first} is represented as an {@link Optional}, this can be * accomplished with {@link Optional#or(Object) first.or(second)}. That approach also allows for * lazy evaluation of the fallback instance, using {@link Optional#or(Supplier) * first.or(supplier)}. * * @return {@code first} if it is non-null; otherwise {@code second} if it is non-null * @throws NullPointerException if both {@code first} and {@code second} are null * @since 18.0 (since 3.0 as {@code Objects.firstNonNull()}. */ public static T firstNonNull(@Nullable T first, @Nullable T second) { return first != null ? first : checkNotNull(second); } /** * Creates an instance of {@link ToStringHelper}. * *

This is helpful for implementing {@link Object#toString()}. * Specification by example:

   {@code
   *   // Returns "ClassName{}"
   *   MoreObjects.toStringHelper(this)
   *       .toString();
   *
   *   // Returns "ClassName{x=1}"
   *   MoreObjects.toStringHelper(this)
   *       .add("x", 1)
   *       .toString();
   *
   *   // Returns "MyObject{x=1}"
   *   MoreObjects.toStringHelper("MyObject")
   *       .add("x", 1)
   *       .toString();
   *
   *   // Returns "ClassName{x=1, y=foo}"
   *   MoreObjects.toStringHelper(this)
   *       .add("x", 1)
   *       .add("y", "foo")
   *       .toString();
   *
   *   // Returns "ClassName{x=1}"
   *   MoreObjects.toStringHelper(this)
   *       .omitNullValues()
   *       .add("x", 1)
   *       .add("y", null)
   *       .toString();
   *   }}
* *

Note that in GWT, class names are often obfuscated. * * @param self the object to generate the string for (typically {@code this}), used only for its * class name * @since 18.0 (since 2.0 as {@code Objects.toStringHelper()}. */ public static ToStringHelper toStringHelper(Object self) { return new ToStringHelper(simpleName(self.getClass())); } /** * Creates an instance of {@link ToStringHelper} in the same manner as {@link * #toStringHelper(Object)}, but using the simple name of {@code clazz} instead of using an * instance's {@link Object#getClass()}. * *

Note that in GWT, class names are often obfuscated. * * @param clazz the {@link Class} of the instance * @since 18.0 (since 7.0 as {@code Objects.toStringHelper()}. */ public static ToStringHelper toStringHelper(Class clazz) { return new ToStringHelper(simpleName(clazz)); } /** * Creates an instance of {@link ToStringHelper} in the same manner as {@link * #toStringHelper(Object)}, but using {@code className} instead of using an instance's {@link * Object#getClass()}. * * @param className the name of the instance type * @since 18.0 (since 7.0 as {@code Objects.toStringHelper()}. */ public static ToStringHelper toStringHelper(String className) { return new ToStringHelper(className); } /** * {@link Class#getSimpleName()} is not GWT compatible yet, so we * provide our own implementation. */ // Package-private so Objects can call it. static String simpleName(Class clazz) { String name = clazz.getName(); // the nth anonymous class has a class name ending in "Outer$n" // and local inner classes have names ending in "Outer.$1Inner" name = name.replaceAll("\\$[0-9]+", "\\$"); // we want the name of the inner class all by its lonesome int start = name.lastIndexOf('$'); // if this isn't an inner class, just find the start of the // top level class name. if (start == -1) { start = name.lastIndexOf('.'); } return name.substring(start + 1); } /** * Support class for {@link MoreObjects#toStringHelper}. * * @author Jason Lee * @since 18.0 (since 2.0 as {@code Objects.ToStringHelper}. */ public static final class ToStringHelper { private final String className; private ValueHolder holderHead = new ValueHolder(); private ValueHolder holderTail = holderHead; private boolean omitNullValues = false; /** * Use {@link MoreObjects#toStringHelper(Object)} to create an instance. */ private ToStringHelper(String className) { this.className = checkNotNull(className); } /** * Configures the {@link ToStringHelper} so {@link #toString()} will ignore * properties with null value. The order of calling this method, relative * to the {@code add()}/{@code addValue()} methods, is not significant. * * @since 18.0 (since 12.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper omitNullValues() { omitNullValues = true; return this; } /** * Adds a name/value pair to the formatted output in {@code name=value} * format. If {@code value} is {@code null}, the string {@code "null"} * is used, unless {@link #omitNullValues()} is called, in which case this * name/value pair will not be added. */ public ToStringHelper add(String name, @Nullable Object value) { return addHolder(name, value); } /** * Adds a name/value pair to the formatted output in {@code name=value} * format. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper add(String name, boolean value) { return addHolder(name, String.valueOf(value)); } /** * Adds a name/value pair to the formatted output in {@code name=value} * format. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper add(String name, char value) { return addHolder(name, String.valueOf(value)); } /** * Adds a name/value pair to the formatted output in {@code name=value} * format. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper add(String name, double value) { return addHolder(name, String.valueOf(value)); } /** * Adds a name/value pair to the formatted output in {@code name=value} * format. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper add(String name, float value) { return addHolder(name, String.valueOf(value)); } /** * Adds a name/value pair to the formatted output in {@code name=value} * format. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper add(String name, int value) { return addHolder(name, String.valueOf(value)); } /** * Adds a name/value pair to the formatted output in {@code name=value} * format. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper add(String name, long value) { return addHolder(name, String.valueOf(value)); } /** * Adds an unnamed value to the formatted output. * *

It is strongly encouraged to use {@link #add(String, Object)} instead * and give value a readable name. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper addValue(@Nullable Object value) { return addHolder(value); } /** * Adds an unnamed value to the formatted output. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. * *

It is strongly encouraged to use {@link #add(String, boolean)} instead * and give value a readable name. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper addValue(boolean value) { return addHolder(String.valueOf(value)); } /** * Adds an unnamed value to the formatted output. * *

It is strongly encouraged to use {@link #add(String, char)} instead * and give value a readable name. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper addValue(char value) { return addHolder(String.valueOf(value)); } /** * Adds an unnamed value to the formatted output. * *

It is strongly encouraged to use {@link #add(String, double)} instead * and give value a readable name. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper addValue(double value) { return addHolder(String.valueOf(value)); } /** * Adds an unnamed value to the formatted output. * *

It is strongly encouraged to use {@link #add(String, float)} instead * and give value a readable name. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper addValue(float value) { return addHolder(String.valueOf(value)); } /** * Adds an unnamed value to the formatted output. * *

It is strongly encouraged to use {@link #add(String, int)} instead * and give value a readable name. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper addValue(int value) { return addHolder(String.valueOf(value)); } /** * Adds an unnamed value to the formatted output. * *

It is strongly encouraged to use {@link #add(String, long)} instead * and give value a readable name. * * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.omitNullValues()}. */ public ToStringHelper addValue(long value) { return addHolder(String.valueOf(value)); } /** * Returns a string in the format specified by * {@link MoreObjects#toStringHelper(Object)}. * *

After calling this method, you can keep adding more properties to later * call toString() again and get a more complete representation of the * same object; but properties cannot be removed, so this only allows * limited reuse of the helper instance. The helper allows duplication of * properties (multiple name/value pairs with the same name can be added). */ @Override public String toString() { // create a copy to keep it consistent in case value changes boolean omitNullValuesSnapshot = omitNullValues; String nextSeparator = ""; StringBuilder builder = new StringBuilder(32).append(className) .append('{'); for (ValueHolder valueHolder = holderHead.next; valueHolder != null; valueHolder = valueHolder.next) { if (!omitNullValuesSnapshot || valueHolder.value != null) { builder.append(nextSeparator); nextSeparator = ", "; if (valueHolder.name != null) { builder.append(valueHolder.name).append('='); } builder.append(valueHolder.value); } } return builder.append('}').toString(); } private ValueHolder addHolder() { ValueHolder valueHolder = new ValueHolder(); holderTail = holderTail.next = valueHolder; return valueHolder; } private ToStringHelper addHolder(@Nullable Object value) { ValueHolder valueHolder = addHolder(); valueHolder.value = value; return this; } private ToStringHelper addHolder(String name, @Nullable Object value) { ValueHolder valueHolder = addHolder(); valueHolder.value = value; valueHolder.name = checkNotNull(name); return this; } private static final class ValueHolder { String name; Object value; ValueHolder next; } } private MoreObjects() {} }





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