All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.fasterxml.jackson.annotation.JsonInclude Maven / Gradle / Ivy

The newest version!
package com.fasterxml.jackson.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Annotation used to indicate when value of the annotated property (when
 * used for a field, method or constructor parameter), or all 
 * properties of the annotated class, is to be serialized.
 * Without annotation property values are always included, but by using
 * this annotation one can specify simple exclusion rules to reduce
 * amount of properties to write out.
 *

* Note that inclusion criteria is checked on Java object level * and NOT on JSON output -- so even with {@link Include#NON_NULL} * it is possible that JSON null values are output, if object reference * in question is not `null`. An example is {@link java.util.concurrent.atomic.AtomicReference} * instance constructed to reference null value: such a value * would be serialized as JSON null, and not filtered out. * In such cases {@link Include#NON_EMPTY} should be used instead, since missing * reference (that is, reference to Java null) is considered "empty" (it is also * considered "default", so match {@link Include#NON_DEFAULT}). * * @since 2.0 */ @Target({ElementType.ANNOTATION_TYPE, ElementType.METHOD, ElementType.FIELD, ElementType.TYPE, ElementType.PARAMETER}) @Retention(RetentionPolicy.RUNTIME) @JacksonAnnotation public @interface JsonInclude { /** * Inclusion rule to use for instances (values) of types (Classes) or * properties annotated. */ public Include value() default Include.ALWAYS; /** * Inclusion rule to use for entries ("content") of annotated * {@link java.util.Map}s; defaults to {@link Include#ALWAYS}. * * @since 2.5 */ public Include content() default Include.ALWAYS; /* /********************************************************** /* Value enumerations needed /********************************************************** */ /** * Enumeration used with {@link JsonInclude} * to define which properties * of Java Beans are to be included in serialization. */ public enum Include { /** * Value that indicates that property is to be always included, * independent of value of the property. */ ALWAYS, /** * Value that indicates that only properties with non-null * values are to be included. */ NON_NULL, /** * Value that indicates that properties are included unless their value * is: *

    *
  • null
  • *
  • "absent" value of a referential type (like Java 8 `Optional`, or * {link java.utl.concurrent.atomic.AtomicReference}); that is, something * that would not deference to a non-null value. *
* This option is mostly used to work with "Optional"s (Java 8, Guava). * * @since 2.6 */ NON_ABSENT, /** * Value that indicates that only properties that have values * that values that are null or what is considered empty are * not to be included. * Definition of emptiness is data type specific; see below * for details on actual handling. *

* Default emptiness is defined for following type: *

    *
  • For {@link java.util.Collection}s and {@link java.util.Map}s, * method isEmpty() is called; *
  • *
  • For Java arrays, empty arrays are ones with length of 0 *
  • *
  • For Java {@link java.lang.String}s, length() is called, * and return value of 0 indicates empty String (note that String.isEmpty() * was added in Java 1.6 and as such can not be used by Jackson *
  • *
  • For date/time types, if timestamp from Epoch is zero (January 1st, 1970, UTC), * value is considered empty. *
  • *
* and for other types, null values are excluded but other exclusions (if any). *

* Note that this default handling can be overridden by custom * JsonSerializer implementation: if method isEmpty() * is overridden, it will be called to see if non-null values are * considered empty (null is always considered empty). */ NON_EMPTY, /** * Value that indicates that only properties that have values * that differ from default settings (meaning values they have * when Bean is constructed with its no-arguments constructor) * are to be included. *

* Note that value does not make sense for * {@link java.util.Map} types, since they have no default values; * and if used, works same as {@link #ALWAYS}. */ NON_DEFAULT, /** * Pseudo-value used to indicate that the higher-level defaults make * sense, to avoid overriding inclusion value. For example, if returned * for a property this would use defaults for the class that contains * property, if any defined; and if none defined for that, then * global serialization inclusion details. * * @since 2.6 */ USE_DEFAULTS ; } /* /********************************************************** /* Value class used to enclose information /********************************************************** */ /** * Helper class used to contain information from a single {@link JsonInclude} * annotation. * * @since 2.6 */ public static class Value implements JacksonAnnotationValue // since 2.6 { protected final static Value EMPTY = new Value(Include.USE_DEFAULTS, Include.USE_DEFAULTS); protected final Include valueInclusion; protected final Include contentInclusion; public Value(JsonInclude src) { this(src.value(), src.content()); } protected Value(Include vi, Include ci) { this.valueInclusion = (vi == null) ? Include.USE_DEFAULTS : vi; this.contentInclusion = (ci == null) ? Include.USE_DEFAULTS : ci; } /** * Mutant factory method that merges values of this value with given override * values, so that any explicitly defined inclusion in overrides has precedence over * settings of this value instance. If no overrides exist will return this * instance; otherwise new {@link Value} with changed inclusion values. */ public Value withOverrides(Value overrides) { if (overrides == null) { return this; } return withValueInclusion(overrides.valueInclusion) .withContentInclusion(overrides.contentInclusion); } public static Value empty() { return EMPTY; } /** * Factory method to use for constructing an instance for components */ public static Value construct(Include valueIncl, Include contentIncl) { if ((valueIncl == Include.USE_DEFAULTS) && (contentIncl == Include.USE_DEFAULTS)) { return EMPTY; } return new Value(valueIncl, contentIncl); } /** * Factory method to use for constructing an instance from instance of * {@link JsonInclude} */ public static Value from(JsonInclude src) { if (src == null) { return null; } return new Value(src); } public Value withValueInclusion(Include incl) { return (incl == valueInclusion) ? this : new Value(incl, contentInclusion); } public Value withContentInclusion(Include incl) { return (incl == contentInclusion) ? this : new Value(valueInclusion, incl); } @Override public Class valueFor() { return JsonInclude.class; } public Include getValueInclusion() { return valueInclusion; } public Include getContentInclusion() { return contentInclusion; } } }





© 2015 - 2024 Weber Informatics LLC | Privacy Policy