http://github.com/FasterXML/jackson: General data-binding functionality for Jackson: works on core streaming API (FasterXML)
  • Tatu Saloranta 
package com.fasterxml.jackson.databind;

import com.fasterxml.jackson.databind.cfg.MapperConfig;
import com.fasterxml.jackson.databind.introspect.AnnotatedField;
import com.fasterxml.jackson.databind.introspect.AnnotatedMethod;
import com.fasterxml.jackson.databind.introspect.AnnotatedParameter;


Class that defines how names of JSON properties ("external names")
are derived from names of POJO methods and fields ("internal names"),
in cases where no explicit annotations exist for naming.
Methods are passed information about POJO member for which name is needed,
as well as default name that would be used if no custom strategy was used.


Default (empty) implementation returns suggested ("implicit" or "default") name unmodified


Note that the strategy is guaranteed to be called once per logical property
(which may be represented by multiple members; such as pair of a getter and
a setter), but may be called for each: implementations should not count on
exact number of times, and should work for any member that represent a
property.
Also note that calls are made during construction of serializers and deserializers
which are typically cached, and not for every time serializer or deserializer
is called.


In absence of a registered custom strategy, the default Java property naming strategy
is used, which leaves field names as is, and removes set/get/is prefix
from methods (as well as lower-cases initial sequence of capitalized
characters).


NOTE! Since 2.12 sub-classes defined here (as well as static singleton instances thereof)
are deprecated due to
databind#2715. Please use constants and classes in PropertyNamingStrategies instead. 
/**
 * Class that defines how names of JSON properties ("external names")
 * are derived from names of POJO methods and fields ("internal names"),
 * in cases where no explicit annotations exist for naming.
 * Methods are passed information about POJO member for which name is needed,
 * as well as default name that would be used if no custom strategy was used.
 *<p>
 * Default (empty) implementation returns suggested ("implicit" or "default") name unmodified
 *<p>
 * Note that the strategy is guaranteed to be called once per logical property
 * (which may be represented by multiple members; such as pair of a getter and
 * a setter), but may be called for each: implementations should not count on
 * exact number of times, and should work for any member that represent a
 * property.
 * Also note that calls are made during construction of serializers and deserializers
 * which are typically cached, and not for every time serializer or deserializer
 * is called.
 *<p>
 * In absence of a registered custom strategy, the default Java property naming strategy
 * is used, which leaves field names as is, and removes set/get/is prefix
 * from methods (as well as lower-cases initial sequence of capitalized
 * characters).
 *<p>
 * NOTE! Since 2.12 sub-classes defined here (as well as static singleton instances thereof)
 * are deprecated due to
 * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>.
 * Please use constants and classes in {@link PropertyNamingStrategies} instead.
 * 
 */
@SuppressWarnings("serial")
public class PropertyNamingStrategy // NOTE: was abstract until 2.7
    implements java.io.Serializable
{
    private static final long serialVersionUID = 2L;

    
Deprecated:Since 2.12 deprecated. Use PropertyNamingStrategies.LOWER_CAMEL_CASE instead. See databind#2715
for reasons for deprecation.
/**
     * @deprecated Since 2.12 deprecated. Use {@link PropertyNamingStrategies#LOWER_CAMEL_CASE} instead.
     * See
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reasons for deprecation.
     */
    @Deprecated // since 2.12
    public static final PropertyNamingStrategy LOWER_CAMEL_CASE = new PropertyNamingStrategy();

    
Deprecated:Since 2.12 deprecated. Use PropertyNamingStrategies.UPPER_CAMEL_CASE instead. See databind#2715
for reasons for deprecation.
/**
     * @deprecated Since 2.12 deprecated. Use {@link PropertyNamingStrategies#UPPER_CAMEL_CASE} instead.
     * See
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reasons for deprecation.
     */
    @Deprecated // since 2.12
    public static final PropertyNamingStrategy UPPER_CAMEL_CASE = new UpperCamelCaseStrategy();

    
Deprecated:Since 2.12 deprecated. Use PropertyNamingStrategies.SNAKE_CASE instead. See databind#2715
for reasons for deprecation.
/**
     * @deprecated Since 2.12 deprecated. Use {@link PropertyNamingStrategies#SNAKE_CASE} instead.
     * See
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reasons for deprecation.
     */
    @Deprecated // since 2.12
    public static final PropertyNamingStrategy SNAKE_CASE = new SnakeCaseStrategy();

    
Deprecated:Since 2.12 deprecated. Use PropertyNamingStrategies.LOWER_CASE instead. See databind#2715
for reasons for deprecation.
/**
     * @deprecated Since 2.12 deprecated. Use {@link PropertyNamingStrategies#LOWER_CASE} instead.
     * See
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reasons for deprecation.
     */
    @Deprecated // since 2.12
    public static final PropertyNamingStrategy LOWER_CASE = new LowerCaseStrategy();

    
Deprecated:Since 2.12 deprecated. Use PropertyNamingStrategies.KEBAB_CASE instead. See databind#2715
for reasons for deprecation.
/**
     * @deprecated Since 2.12 deprecated. Use {@link PropertyNamingStrategies#KEBAB_CASE} instead.
     * See
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reasons for deprecation.
     */
    @Deprecated // since 2.12
    public static final PropertyNamingStrategy KEBAB_CASE = new KebabCaseStrategy();

    
Deprecated:Since 2.12 deprecated. Use PropertyNamingStrategies.LOWER_DOT_CASE instead. See databind#2715
for reasons for deprecation.
/**
     * @deprecated Since 2.12 deprecated. Use {@link PropertyNamingStrategies#LOWER_DOT_CASE} instead.
     * See
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reasons for deprecation.
     */
    @Deprecated // since 2.12
    public static final PropertyNamingStrategy LOWER_DOT_CASE = new LowerDotCaseStrategy();

    /*
    /**********************************************************
    /* API
    /**********************************************************
     */

    
Method called to find external name (name used in JSON) for given logical
POJO property,
as defined by given field.

Params:
  • config – Configuration in used: either SerializationConfig
  or DeserializationConfig, depending on whether method is called
  during serialization or deserialization
  • field – Field used to access property
  • defaultName – Default name that would be used for property in absence of custom strategy
Returns:Logical name to use for property that the field represents
/**
     * Method called to find external name (name used in JSON) for given logical
     * POJO property,
     * as defined by given field.
     * 
     * @param config Configuration in used: either <code>SerializationConfig</code>
     *   or <code>DeserializationConfig</code>, depending on whether method is called
     *   during serialization or deserialization
     * @param field Field used to access property
     * @param defaultName Default name that would be used for property in absence of custom strategy
     * 
     * @return Logical name to use for property that the field represents
     */
    public String nameForField(MapperConfig<?> config, AnnotatedField field,
            String defaultName)
    {
        return defaultName;
    }

    
Method called to find external name (name used in JSON) for given logical
POJO property,
as defined by given getter method; typically called when building a serializer.
(but not always -- when using "getter-as-setter", may be called during
deserialization)

Params:
  • config – Configuration in used: either SerializationConfig
  or DeserializationConfig, depending on whether method is called
  during serialization or deserialization
  • method – Method used to access property.
  • defaultName – Default name that would be used for property in absence of custom strategy
Returns:Logical name to use for property that the method represents
/**
     * Method called to find external name (name used in JSON) for given logical
     * POJO property,
     * as defined by given getter method; typically called when building a serializer.
     * (but not always -- when using "getter-as-setter", may be called during
     * deserialization)
     * 
     * @param config Configuration in used: either <code>SerializationConfig</code>
     *   or <code>DeserializationConfig</code>, depending on whether method is called
     *   during serialization or deserialization
     * @param method Method used to access property.
     * @param defaultName Default name that would be used for property in absence of custom strategy
     * 
     * @return Logical name to use for property that the method represents
     */
    public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method,
            String defaultName)
    {
        return defaultName;
    }

    
Method called to find external name (name used in JSON) for given logical
POJO property,
as defined by given setter method; typically called when building a deserializer
(but not necessarily only then).

Params:
  • config – Configuration in used: either SerializationConfig
  or DeserializationConfig, depending on whether method is called
  during serialization or deserialization
  • method – Method used to access property.
  • defaultName – Default name that would be used for property in absence of custom strategy
Returns:Logical name to use for property that the method represents
/**
     * Method called to find external name (name used in JSON) for given logical
     * POJO property,
     * as defined by given setter method; typically called when building a deserializer
     * (but not necessarily only then).
     * 
     * @param config Configuration in used: either <code>SerializationConfig</code>
     *   or <code>DeserializationConfig</code>, depending on whether method is called
     *   during serialization or deserialization
     * @param method Method used to access property.
     * @param defaultName Default name that would be used for property in absence of custom strategy
     * 
     * @return Logical name to use for property that the method represents
     */
    public String nameForSetterMethod(MapperConfig<?> config, AnnotatedMethod method,
            String defaultName)
    {
        return defaultName;
    }

    
Method called to find external name (name used in JSON) for given logical
POJO property,
as defined by given constructor parameter; typically called when building a deserializer
(but not necessarily only then).

Params:
  • config – Configuration in used: either SerializationConfig
  or DeserializationConfig, depending on whether method is called
  during serialization or deserialization
  • ctorParam – Constructor parameter used to pass property.
  • defaultName – Default name that would be used for property in absence of custom strategy
/**
     * Method called to find external name (name used in JSON) for given logical
     * POJO property,
     * as defined by given constructor parameter; typically called when building a deserializer
     * (but not necessarily only then).
     * 
     * @param config Configuration in used: either <code>SerializationConfig</code>
     *   or <code>DeserializationConfig</code>, depending on whether method is called
     *   during serialization or deserialization
     * @param ctorParam Constructor parameter used to pass property.
     * @param defaultName Default name that would be used for property in absence of custom strategy
     */
    public String nameForConstructorParameter(MapperConfig<?> config, AnnotatedParameter ctorParam,
            String defaultName)
    {
        return defaultName;
    }

    /*
    /**********************************************************
    /* Public base class for simple implementations
    /**********************************************************
     */

    
Deprecated:Since 2.12 deprecated. See
databind#2715
for reasons for deprecation.
/**
     * @deprecated Since 2.12 deprecated. See
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reasons for deprecation.
     */
    @Deprecated
    public static abstract class PropertyNamingStrategyBase extends PropertyNamingStrategy
    {
        @Override
        public String nameForField(MapperConfig<?> config, AnnotatedField field, String defaultName)
        {
            return translate(defaultName);
        }

        @Override
        public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName)
        {
            return translate(defaultName);
        }

        @Override
        public String nameForSetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName)
        {
            return translate(defaultName);
        }

        @Override
        public String nameForConstructorParameter(MapperConfig<?> config, AnnotatedParameter ctorParam,
                String defaultName)
        {
            return translate(defaultName);
        }
        
        public abstract String translate(String propertyName);

        
Helper method to share implementation between snake and dotted case.

/**
         * Helper method to share implementation between snake and dotted case.
         */
        protected static String translateLowerCaseWithSeparator(final String input, final char separator)
        {
            if (input == null) {
                return input; // garbage in, garbage out
            }
            final int length = input.length();
            if (length == 0) {
                return input;
            }
    
            final StringBuilder result = new StringBuilder(length + (length >> 1));
            int upperCount = 0;
            for (int i = 0; i < length; ++i) {
                char ch = input.charAt(i);
                char lc = Character.toLowerCase(ch);
    
                if (lc == ch) { // lower-case letter means we can get new word
                    // but need to check for multi-letter upper-case (acronym), where assumption
                    // is that the last upper-case char is start of a new word
                    if (upperCount > 1) {
                        // so insert hyphen before the last character now
                        result.insert(result.length() - 1, separator);
                    }
                    upperCount = 0;
                } else {
                    // Otherwise starts new word, unless beginning of string
                    if ((upperCount == 0) && (i > 0)) {
                        result.append(separator);
                    }
                    ++upperCount;
                }
                result.append(lc);
            }
            return result.toString();
        }
    }

    /*
    /**********************************************************
    /* Standard implementations 
    /**********************************************************
     */
    
    
Deprecated:Since 2.12 use SnakeCaseStrategy instead (see databind#2715
for reason for deprecation)
/**
     * @deprecated Since 2.12 use {@link PropertyNamingStrategies.SnakeCaseStrategy} instead
     * (see
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reason for deprecation)
     */
    @Deprecated // since 2.12
    public static class SnakeCaseStrategy extends PropertyNamingStrategyBase
    {
        @Override
        public String translate(String input)
        {
            if (input == null) return input; // garbage in, garbage out
            int length = input.length();
            StringBuilder result = new StringBuilder(length * 2);
            int resultLength = 0;
            boolean wasPrevTranslated = false;
            for (int i = 0; i < length; i++)
            {
                char c = input.charAt(i);
                if (i > 0 || c != '_') // skip first starting underscore
                {
                    if (Character.isUpperCase(c))
                    {
                        if (!wasPrevTranslated && resultLength > 0 && result.charAt(resultLength - 1) != '_')
                        {
                            result.append('_');
                            resultLength++;
                        }
                        c = Character.toLowerCase(c);
                        wasPrevTranslated = true;
                    }
                    else
                    {
                        wasPrevTranslated = false;
                    }
                    result.append(c);
                    resultLength++;
                }
            }
            return resultLength > 0 ? result.toString() : input;
        }
    }

    
Deprecated:Since 2.12 use UpperCamelCaseStrategy instead (see databind#2715
for reason for deprecation)
/**
     * @deprecated Since 2.12 use {@link PropertyNamingStrategies.UpperCamelCaseStrategy} instead
     * (see
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reason for deprecation)
     */
    @Deprecated // since 2.12
    public static class UpperCamelCaseStrategy extends PropertyNamingStrategyBase
    {
        
Converts camelCase to PascalCase
For example, "userName" would be converted to
"UserName".

Params:
  • input – formatted as camelCase string
Returns:input converted to PascalCase format
/**
         * Converts camelCase to PascalCase
         * 
         * For example, "userName" would be converted to
         * "UserName".
         *
         * @param input formatted as camelCase string
         * @return input converted to PascalCase format
         */
        @Override
        public String translate(String input) {
            if (input == null || input.isEmpty()){
                return input; // garbage in, garbage out
            }
            // Replace first lower-case letter with upper-case equivalent
            char c = input.charAt(0);
            char uc = Character.toUpperCase(c);
            if (c == uc) {
                return input;
            }
            StringBuilder sb = new StringBuilder(input);
            sb.setCharAt(0, uc);
            return sb.toString();
        }
    }

    
Deprecated:Since 2.12 use LowerCaseStrategy instead (see databind#2715
for reason for deprecation)
/**
     * @deprecated Since 2.12 use {@link PropertyNamingStrategies.LowerCaseStrategy} instead
     * (see
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reason for deprecation)
     */
    @Deprecated // since 2.12
    public static class LowerCaseStrategy extends PropertyNamingStrategyBase
    {
        @Override
        public String translate(String input) {
            return input.toLowerCase();
        }
    }

    
Deprecated:Since 2.12 use KebabCaseStrategy instead (see databind#2715
for reason for deprecation)
/**
     * @deprecated Since 2.12 use {@link PropertyNamingStrategies.KebabCaseStrategy} instead
     * (see
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reason for deprecation)
     */
    @Deprecated // since 2.12
    public static class KebabCaseStrategy extends PropertyNamingStrategyBase
    {
        @Override
        public String translate(String input) {
            return translateLowerCaseWithSeparator(input, '-');
        }
    }

    
Deprecated:Since 2.12 use LowerDotCaseStrategy instead (see databind#2715
for reason for deprecation)
/**
     * @deprecated Since 2.12 use {@link PropertyNamingStrategies.LowerDotCaseStrategy} instead
     * (see
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2715">databind#2715</a>
     * for reason for deprecation)
     */
    @Deprecated // since 2.12
    public static class LowerDotCaseStrategy extends PropertyNamingStrategyBase {
        @Override
        public String translate(String input){
            return translateLowerCaseWithSeparator(input, '.');
        }
    }

    /*
    /**********************************************************
    /* Deprecated variants, aliases
    /**********************************************************
     */

    
Deprecated:Since 2.7 use PropertyNamingStrategies.SNAKE_CASE instead.
/**
     * @deprecated Since 2.7 use {@link PropertyNamingStrategies#SNAKE_CASE} instead.
     */
    @Deprecated // since 2.7
    public static final PropertyNamingStrategy CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES = SNAKE_CASE;

    
Deprecated:Since 2.7 use PropertyNamingStrategies.UPPER_CAMEL_CASE instead;
/**
     * @deprecated Since 2.7 use {@link PropertyNamingStrategies#UPPER_CAMEL_CASE} instead;
     */
    @Deprecated // since 2.7
    public static final PropertyNamingStrategy PASCAL_CASE_TO_CAMEL_CASE = UPPER_CAMEL_CASE;

    
Deprecated:In 2.7 use SnakeCaseStrategy instead
/**
     * @deprecated In 2.7 use {@link PropertyNamingStrategies.SnakeCaseStrategy} instead
     */
    @Deprecated // since 2.7
    public static class LowerCaseWithUnderscoresStrategy extends SnakeCaseStrategy {}

    
Deprecated:In 2.7 use UpperCamelCaseStrategy instead
/**
     * @deprecated In 2.7 use {@link PropertyNamingStrategies.UpperCamelCaseStrategy} instead
     */
    @Deprecated // since 2.7
    public static class PascalCaseStrategy extends UpperCamelCaseStrategy { }
}