package com.fasterxml.jackson.dataformat.avro.schema;

import java.io.File;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.net.URI;
import java.net.URL;
import java.util.*;

import org.apache.avro.Schema;
import org.apache.avro.Schema.Parser;
import org.apache.avro.reflect.AvroAlias;
import org.apache.avro.reflect.Stringable;
import org.apache.avro.specific.SpecificData;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.BeanDescription;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.introspect.AnnotatedClass;
import com.fasterxml.jackson.databind.introspect.AnnotatedConstructor;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatTypes;
import com.fasterxml.jackson.databind.util.ClassUtil;

public abstract class AvroSchemaHelper
{
    
Constant used by native Avro Schemas for indicating more specific physical class of a value; referenced indirectly to reduce direct dependencies to the standard avro library.
Since:2.8.7
/** * Constant used by native Avro Schemas for indicating more specific * physical class of a value; referenced indirectly to reduce direct * dependencies to the standard avro library. * * @since 2.8.7 */
public static final String AVRO_SCHEMA_PROP_CLASS = SpecificData.CLASS_PROP;
Constant used by native Avro Schemas for indicating more specific physical class of a map key; referenced indirectly to reduce direct dependencies to the standard avro library.
Since:2.8.7
/** * Constant used by native Avro Schemas for indicating more specific * physical class of a map key; referenced indirectly to reduce direct * dependencies to the standard avro library. * * @since 2.8.7 */
public static final String AVRO_SCHEMA_PROP_KEY_CLASS = SpecificData.KEY_CLASS_PROP;
Constant used by native Avro Schemas for indicating more specific physical class of a array element; referenced indirectly to reduce direct dependencies to the standard avro library.
Since:2.8.8
/** * Constant used by native Avro Schemas for indicating more specific * physical class of a array element; referenced indirectly to reduce direct * dependencies to the standard avro library. * * @since 2.8.8 */
public static final String AVRO_SCHEMA_PROP_ELEMENT_CLASS = SpecificData.ELEMENT_PROP;
Default stringable classes
Since:2.8.7
/** * Default stringable classes * * @since 2.8.7 */
protected static final Set<Class<?>> STRINGABLE_CLASSES = new HashSet<Class<?>>(Arrays.asList( URI.class, URL.class, File.class, BigInteger.class, BigDecimal.class, String.class ));
Checks if a given type is "Stringable", that is one of the default STRINGABLE_CLASSES, is an Enum, or is annotated with @Stringable and has a constructor that takes a single string argument capable of deserializing the output of its toString() method.
Params:
  • type – Type to check if it can be serialized to a Avro string schema
Returns:true if it can be stored in a string schema, otherwise false
/** * Checks if a given type is "Stringable", that is one of the default * {@code STRINGABLE_CLASSES}, is an {@code Enum}, * or is annotated with * {@link Stringable @Stringable} and has a constructor that takes a single string argument capable of deserializing the output of its * {@code toString()} method. * * @param type * Type to check if it can be serialized to a Avro string schema * * @return {@code true} if it can be stored in a string schema, otherwise {@code false} */
public static boolean isStringable(AnnotatedClass type) { if (STRINGABLE_CLASSES.contains(type.getRawType()) || Enum.class.isAssignableFrom(type.getRawType())) { return true; } if (type.getAnnotated().getAnnotation(Stringable.class) == null) { return false; } for (AnnotatedConstructor constructor : type.getConstructors()) { if (constructor.getParameterCount() == 1 && constructor.getRawParameterType(0) == String.class) { return true; } } return false; } protected static String getNamespace(JavaType type) { Class<?> cls = type.getRawClass(); // 16-Feb-2017, tatu: Fixed as suggested by `baharclerode@github`; // NOTE: was reverted in 2.8.8, but is enabled for Jackson 2.9. Class<?> enclosing = cls.getEnclosingClass(); if (enclosing != null) { return enclosing.getName() + "$"; } Package pkg = cls.getPackage(); return (pkg == null) ? "" : pkg.getName(); } protected static String getName(JavaType type) { String name = type.getRawClass().getSimpleName(); // Alas, some characters not accepted... while (name.indexOf("[]") >= 0) { name = name.replace("[]", "Array"); } return name; } protected static Schema unionWithNull(Schema otherSchema) { List<Schema> schemas = new ArrayList<Schema>(); schemas.add(Schema.create(Schema.Type.NULL)); // two cases: existing union if (otherSchema.getType() == Schema.Type.UNION) { schemas.addAll(otherSchema.getTypes()); } else { // and then simpler case, no union schemas.add(otherSchema); } return Schema.createUnion(schemas); } public static Schema simpleSchema(JsonFormatTypes type, JavaType hint) { switch (type) { case BOOLEAN: return Schema.create(Schema.Type.BOOLEAN); case INTEGER: return Schema.create(Schema.Type.INT); case NULL: return Schema.create(Schema.Type.NULL); case NUMBER: // 16-Feb-2017, tatu: Fixed as suggested by `baharclerode@github` if (hint.hasRawClass(float.class)) { return Schema.create(Schema.Type.FLOAT); } if (hint.hasRawClass(long.class)) { return Schema.create(Schema.Type.LONG); } return Schema.create(Schema.Type.DOUBLE); case STRING: return Schema.create(Schema.Type.STRING); case ARRAY: case OBJECT: throw new UnsupportedOperationException("Should not try to create simple Schema for: "+type); case ANY: // might be able to support in future default: throw new UnsupportedOperationException("Can not create Schema for: "+type+"; not (yet) supported"); } } public static Schema numericAvroSchema(JsonParser.NumberType type) { switch (type) { case INT: return Schema.create(Schema.Type.INT); case LONG: return Schema.create(Schema.Type.LONG); case FLOAT: return Schema.create(Schema.Type.FLOAT); case DOUBLE: return Schema.create(Schema.Type.DOUBLE); case BIG_INTEGER: case BIG_DECIMAL: return Schema.create(Schema.Type.STRING); default: } throw new IllegalStateException("Unrecognized number type: "+type); } public static Schema numericAvroSchema(JsonParser.NumberType type, JavaType hint) { Schema schema = numericAvroSchema(type); if (hint != null) { schema.addProp(AVRO_SCHEMA_PROP_CLASS, getTypeId(hint)); } return schema; }
Helper method for constructing type-tagged "native" Avro Schema instance.
Since:2.8.7
/** * Helper method for constructing type-tagged "native" Avro Schema instance. * * @since 2.8.7 */
public static Schema typedSchema(Schema.Type nativeType, JavaType javaType) { Schema schema = Schema.create(nativeType); schema.addProp(AVRO_SCHEMA_PROP_CLASS, getTypeId(javaType)); return schema; } public static Schema anyNumberSchema() { return Schema.createUnion(Arrays.asList( Schema.create(Schema.Type.INT), Schema.create(Schema.Type.LONG), Schema.create(Schema.Type.DOUBLE) )); } public static Schema stringableKeyMapSchema(JavaType mapType, JavaType keyType, Schema valueSchema) { Schema schema = Schema.createMap(valueSchema); if (mapType != null && !mapType.hasRawClass(Map.class)) { schema.addProp(AVRO_SCHEMA_PROP_CLASS, getTypeId(mapType)); } if (keyType != null && !keyType.hasRawClass(String.class)) { schema.addProp(AVRO_SCHEMA_PROP_KEY_CLASS, getTypeId(keyType)); } return schema; } protected static <T> T throwUnsupported() { throw new UnsupportedOperationException("Format variation not supported"); }
Initializes a record schema with metadata from the given class; this schema is returned in a non-finalized state, and still needs to have fields added to it.
/** * Initializes a record schema with metadata from the given class; this schema is returned in a non-finalized state, and still * needs to have fields added to it. */
public static Schema initializeRecordSchema(BeanDescription bean) { return addAlias(Schema.createRecord( getName(bean.getType()), bean.findClassDescription(), getNamespace(bean.getType()), bean.getType().isTypeOrSubTypeOf(Throwable.class) ), bean); }
Parses a JSON-formatted representation of a schema
/** * Parses a JSON-formatted representation of a schema */
public static Schema parseJsonSchema(String json) { Schema.Parser parser = new Parser(); return parser.parse(json); }
Constructs a new enum schema
Params:
  • bean – Enum type to use for name / description / namespace
  • values – List of enum names
Returns:An ENUM schema.
/** * Constructs a new enum schema * * @param bean Enum type to use for name / description / namespace * @param values List of enum names * @return An {@link org.apache.avro.Schema.Type#ENUM ENUM} schema. */
public static Schema createEnumSchema(BeanDescription bean, List<String> values) { return addAlias(Schema.createEnum( getName(bean.getType()), bean.findClassDescription(), getNamespace(bean.getType()), values ), bean); }
Looks for @AvroAlias on bean and adds it to schema if it exists
Params:
  • schema – Schema to which the alias should be added
  • bean – Bean to inspect for type aliases
Returns:schema, possibly with an alias added
/** * Looks for {@link AvroAlias @AvroAlias} on {@code bean} and adds it to {@code schema} if it exists * @param schema Schema to which the alias should be added * @param bean Bean to inspect for type aliases * @return {@code schema}, possibly with an alias added */
public static Schema addAlias(Schema schema, BeanDescription bean) { AvroAlias ann = bean.getClassInfo().getAnnotation(AvroAlias.class); if (ann != null) { schema.addAlias(ann.alias(), ann.space().equals(AvroAlias.NULL) ? null : ann.space()); } return schema; } public static String getTypeId(JavaType type) { return getTypeId(type.getRawClass()); }
Returns the Avro type ID for a given type
/** * Returns the Avro type ID for a given type */
public static String getTypeId(Class<?> type) { // Primitives use the name of the wrapper class as their type ID if (type.isPrimitive()) { return ClassUtil.wrapperType(type).getName(); } return type.getName(); }
Returns the type ID for this schema, or null if none is present.
/** * Returns the type ID for this schema, or {@code null} if none is present. */
public static String getTypeId(Schema schema) { switch (schema.getType()) { case RECORD: case ENUM: case FIXED: return getFullName(schema); default: return schema.getProp(AVRO_SCHEMA_PROP_CLASS); } }
Returns the full name of a schema; This is similar to Schema.getFullName(), except that it properly handles namespaces for nested classes. (package.name.ClassName$NestedClassName instead of package.name.ClassName$.NestedClassName)
/** * Returns the full name of a schema; This is similar to {@link Schema#getFullName()}, except that it properly handles namespaces for * nested classes. (<code>package.name.ClassName$NestedClassName</code> instead of <code>package.name.ClassName$.NestedClassName</code>) */
public static String getFullName(Schema schema) { switch (schema.getType()) { case RECORD: case ENUM: case FIXED: String namespace = schema.getNamespace(); String name = schema.getName(); if (namespace == null) { return schema.getName(); } if (namespace.endsWith("$")) { return namespace + name; } StringBuilder sb = new StringBuilder(1 + namespace.length() + name.length()); return sb.append(namespace).append('.').append(name).toString(); default: return schema.getType().getName(); } } }