parquet.schema.Types Maven / Gradle / Ivy
package parquet.schema;
import java.util.ArrayList;
import java.util.List;
import parquet.Preconditions;
import parquet.schema.PrimitiveType.PrimitiveTypeName;
/**
* This class provides fluent builders that produce Parquet schema Types.
*
* The most basic use is to build primitive types:
*
* Types.required(INT64).named("id");
* Types.optional(INT32).named("number");
*
*
* The {@link #required(PrimitiveTypeName)} factory method produces a primitive
* type builder, and the {@link PrimitiveBuilder#named(String)} builds the
* {@link PrimitiveType}. Between {@code required} and {@code named}, other
* builder methods can be used to add type annotations or other type metadata:
*
* Types.required(BINARY).as(UTF8).named("username");
* Types.optional(FIXED_LEN_BYTE_ARRAY).length(20).named("sha1");
*
*
* Optional types are built using {@link #optional(PrimitiveTypeName)} to get
* the builder.
*
* Groups are built similarly, using {@code requiredGroup()} (or the optional
* version) to return a group builder. Group builders provide {@code required}
* and {@code optional} to add primitive types, which return primitive builders
* like the versions above.
*
* // This produces:
* // required group User {
* // required int64 id;
* // optional binary email (UTF8);
* // }
* Types.requiredGroup()
* .required(INT64).named("id")
* .required(BINARY).as(UTF8).named("email")
* .named("User")
*
*
* When {@code required} is called on a group builder, the builder it returns
* will add the type to the parent group when it is built and {@code named} will
* return its parent group builder (instead of the type) so more fields can be
* added.
*
* Sub-groups can be created using {@code requiredGroup()} to get a group
* builder that will create the group type, add it to the parent builder, and
* return the parent builder for more fields.
*
* // required group User {
* // required int64 id;
* // optional binary email (UTF8);
* // optional group address {
* // required binary street (UTF8);
* // required int32 zipcode;
* // }
* // }
* Types.requiredGroup()
* .required(INT64).named("id")
* .required(BINARY).as(UTF8).named("email")
* .optionalGroup()
* .required(BINARY).as(UTF8).named("street")
* .required(INT32).named("zipcode")
* .named("address")
* .named("User")
*
*
* Message types are built using {@link #buildMessage()} and function just like
* group builders.
*
* // message User {
* // required int64 id;
* // optional binary email (UTF8);
* // optional group address {
* // required binary street (UTF8);
* // required int32 zipcode;
* // }
* // }
* Types.buildMessage()
* .required(INT64).named("id")
* .required(BINARY).as(UTF8).named("email")
* .optionalGroup()
* .required(BINARY).as(UTF8).named("street")
* .required(INT32).named("zipcode")
* .named("address")
* .named("User")
*
*
* These builders enforce consistency checks based on the specifications in
* the parquet-format documentation. For example, if DECIMAL is used to annotate
* a FIXED_LEN_BYTE_ARRAY that is not long enough for its maximum precision,
* these builders will throw an IllegalArgumentException:
*
* // throws IllegalArgumentException with message:
* // "FIXED(4) is not long enough to store 10 digits"
* Types.required(FIXED_LEN_BYTE_ARRAY).length(4)
* .as(DECIMAL).precision(10)
* .named("badDecimal");
*
*/
public class Types {
private static final int NOT_SET = 0;
/**
* A base builder for {@link Type} objects.
*
* @param The type that this builder will return from
* {@link #named(String)} when the type is built.
*/
public abstract static class Builder {
protected final P parent;
protected final Class returnClass;
protected Type.Repetition repetition = null;
protected OriginalType originalType = null;
private boolean repetitionAlreadySet = false;
/**
* Construct a type builder that returns a "parent" object when the builder
* is finished. The {@code parent} will be returned by
* {@link #named(String)} so that builders can be chained.
*
* @param parent a non-null object to return from {@link #named(String)}
*/
protected Builder(P parent) {
Preconditions.checkNotNull(parent, "Parent cannot be null");
this.parent = parent;
this.returnClass = null;
}
/**
* Construct a type builder that returns the {@link Type} that was built
* when the builder is finished. The {@code returnClass} must be the
* expected {@code Type} class.
*
* @param returnClass a {@code Type} to return from {@link #named(String)}
*/
protected Builder(Class returnClass) {
Preconditions.checkArgument(Type.class.isAssignableFrom(returnClass),
"The requested return class must extend Type");
this.returnClass = returnClass;
this.parent = null;
}
protected abstract T self();
protected final T repetition(Type.Repetition repetition) {
Preconditions.checkArgument(!repetitionAlreadySet,
"Repetition has already been set");
Preconditions.checkNotNull(repetition, "Repetition cannot be null");
this.repetition = repetition;
this.repetitionAlreadySet = true;
return self();
}
/**
* Adds a type annotation ({@link OriginalType}) to the type being built.
*
* Type annotations are used to extend the types that parquet can store, by
* specifying how the primitive types should be interpreted. This keeps the
* set of primitive types to a minimum and reuses parquet's efficient
* encodings. For example, strings are stored as byte arrays (binary) with
* a UTF8 annotation.
*
* @param type an {@code OriginalType}
* @return this builder for method chaining
*/
public T as(OriginalType type) {
this.originalType = type;
return self();
}
abstract protected Type build(String name);
/**
* Builds a {@link Type} and returns the parent builder, if given, or the
* {@code Type} that was built. If returning a parent object that is a
* GroupBuilder, the constructed type will be added to it as a field.
*
* Note: Any configuration for this type builder should be done
* before calling this method.
*
* @param name a name for the constructed type
* @return the parent {@code GroupBuilder} or the constructed {@code Type}
*/
public P named(String name) {
Preconditions.checkNotNull(name, "Name is required");
Preconditions.checkNotNull(repetition, "Repetition is required");
Type type = build(name);
if (parent != null) {
// if the parent is a GroupBuilder, add type to it
if (GroupBuilder.class.isAssignableFrom(parent.getClass())) {
GroupBuilder.class.cast(parent).addField(type);
}
return parent;
} else {
// no parent indicates that the Type object should be returned
// the constructor check guarantees that returnClass is a Type
return returnClass.cast(type);
}
}
}
/**
* A builder for {@link PrimitiveType} objects.
*
* @param
The type that this builder will return from
* {@link #named(String)} when the type is built.
*/
public static class PrimitiveBuilder
extends Builder, P> {
private static final long MAX_PRECISION_INT32 = maxPrecision(4);
private static final long MAX_PRECISION_INT64 = maxPrecision(8);
private final PrimitiveTypeName primitiveType;
private int length = NOT_SET;
private int precision = NOT_SET;
private int scale = NOT_SET;
private PrimitiveBuilder(P parent, PrimitiveTypeName type) {
super(parent);
this.primitiveType = type;
}
private PrimitiveBuilder(Class returnType, PrimitiveTypeName type) {
super(returnType);
this.primitiveType = type;
}
@Override
protected PrimitiveBuilder
self() {
return this;
}
/**
* Adds the length for a FIXED_LEN_BYTE_ARRAY.
*
* @param length an int length
* @return this builder for method chaining
*/
public PrimitiveBuilder
length(int length) {
this.length = length;
return this;
}
/**
* Adds the precision for a DECIMAL.
*
* This value is required for decimals and must be less than or equal to
* the maximum number of base-10 digits in the underlying type. A 4-byte
* fixed, for example, can store up to 9 base-10 digits.
*
* @param precision an int precision value for the DECIMAL
* @return this builder for method chaining
*/
public PrimitiveBuilder
precision(int precision) {
this.precision = precision;
return this;
}
/**
* Adds the scale for a DECIMAL.
*
* This value must be less than the maximum precision of the type and must
* be a positive number. If not set, the default scale is 0.
*
* The scale specifies the number of digits of the underlying unscaled
* that are to the right of the decimal point. The decimal interpretation
* of values in this column is: {@code value*10^(-scale)}.
*
* @param scale an int scale value for the DECIMAL
* @return this builder for method chaining
*/
public PrimitiveBuilder
scale(int scale) {
this.scale = scale;
return this;
}
@Override
protected PrimitiveType build(String name) {
if (PrimitiveTypeName.FIXED_LEN_BYTE_ARRAY == primitiveType) {
Preconditions.checkArgument(length > 0,
"Invalid FIXED_LEN_BYTE_ARRAY length: " + length);
}
DecimalMetadata meta = decimalMetadata();
// validate type annotations and required metadata
if (originalType != null) {
switch (originalType) {
case UTF8:
Preconditions.checkState(
primitiveType == PrimitiveTypeName.BINARY,
"UTF8 can only annotate binary fields");
break;
case DECIMAL:
Preconditions.checkState(
(primitiveType == PrimitiveTypeName.INT32) ||
(primitiveType == PrimitiveTypeName.INT64) ||
(primitiveType == PrimitiveTypeName.BINARY) ||
(primitiveType == PrimitiveTypeName.FIXED_LEN_BYTE_ARRAY),
"DECIMAL can only annotate INT32, INT64, BINARY, and FIXED"
);
if (primitiveType == PrimitiveTypeName.INT32) {
Preconditions.checkState(
meta.getPrecision() <= MAX_PRECISION_INT32,
"INT32 cannot store " + meta.getPrecision() + " digits " +
"(max " + MAX_PRECISION_INT32 + ")");
} else if (primitiveType == PrimitiveTypeName.INT64) {
Preconditions.checkState(
meta.getPrecision() <= MAX_PRECISION_INT64,
"INT64 cannot store " + meta.getPrecision() + " digits " +
"(max " + MAX_PRECISION_INT64 + ")");
} else if (primitiveType == PrimitiveTypeName.FIXED_LEN_BYTE_ARRAY) {
Preconditions.checkState(
meta.getPrecision() <= maxPrecision(length),
"FIXED(" + length + ") cannot store " + meta.getPrecision() +
" digits (max " + maxPrecision(length) + ")");
}
}
}
return new PrimitiveType(
repetition, primitiveType, length, name, originalType, meta);
}
private static long maxPrecision(int numBytes) {
return Math.round( // convert double to long
Math.floor(Math.log10( // number of base-10 digits
Math.pow(2, 8 * numBytes - 1) - 1) // max value stored in numBytes
)
);
}
protected DecimalMetadata decimalMetadata() {
DecimalMetadata meta = null;
if (OriginalType.DECIMAL == originalType) {
Preconditions.checkArgument(precision > 0,
"Invalid DECIMAL precision: " + precision);
Preconditions.checkArgument(scale >= 0,
"Invalid DECIMAL scale: " + scale);
Preconditions.checkArgument(scale <= precision,
"Invalid DECIMAL scale: cannot be greater than precision");
meta = new DecimalMetadata(precision, scale);
}
return meta;
}
}
/**
* A builder for {@link GroupType} objects.
*
* @param
The type that this builder will return from
* {@link #named(String)} when the type is built.
*/
public static class GroupBuilder
extends Builder, P> {
protected final List fields;
private GroupBuilder(P parent) {
super(parent);
this.fields = new ArrayList();
}
private GroupBuilder(Class returnType) {
super(returnType);
this.fields = new ArrayList();
}
@Override
protected GroupBuilder self() {
return this;
}
public PrimitiveBuilder> primitive(
PrimitiveTypeName type, Type.Repetition repetition) {
return new PrimitiveBuilder>(this, type)
.repetition(repetition);
}
/**
* Returns a {@link PrimitiveBuilder} for the required primitive type
* {@code type}.
*
* @param type a {@link PrimitiveTypeName}
* @return a primitive builder for {@code type} that will return this
* builder for additional fields.
*/
public PrimitiveBuilder> required(
PrimitiveTypeName type) {
return new PrimitiveBuilder>(this, type)
.repetition(Type.Repetition.REQUIRED);
}
/**
* Returns a {@link PrimitiveBuilder} for the optional primitive type
* {@code type}.
*
* @param type a {@link PrimitiveTypeName}
* @return a primitive builder for {@code type} that will return this
* builder for additional fields.
*/
public PrimitiveBuilder> optional(
PrimitiveTypeName type) {
return new PrimitiveBuilder>(this, type)
.repetition(Type.Repetition.OPTIONAL);
}
/**
* Returns a {@link PrimitiveBuilder} for the repeated primitive type
* {@code type}.
*
* @param type a {@link PrimitiveTypeName}
* @return a primitive builder for {@code type} that will return this
* builder for additional fields.
*/
public PrimitiveBuilder> repeated(
PrimitiveTypeName type) {
return new PrimitiveBuilder>(this, type)
.repetition(Type.Repetition.REPEATED);
}
public GroupBuilder> group(Type.Repetition repetition) {
return new GroupBuilder>(this)
.repetition(repetition);
}
/**
* Returns a {@link GroupBuilder} to build a required sub-group.
*
* @return a group builder that will return this builder for additional
* fields.
*/
public GroupBuilder> requiredGroup() {
return new GroupBuilder>(this)
.repetition(Type.Repetition.REQUIRED);
}
/**
* Returns a {@link GroupBuilder} to build an optional sub-group.
*
* @return a group builder that will return this builder for additional
* fields.
*/
public GroupBuilder> optionalGroup() {
return new GroupBuilder>(this)
.repetition(Type.Repetition.OPTIONAL);
}
/**
* Returns a {@link GroupBuilder} to build a repeated sub-group.
*
* @return a group builder that will return this builder for additional
* fields.
*/
public GroupBuilder> repeatedGroup() {
return new GroupBuilder>(this)
.repetition(Type.Repetition.REPEATED);
}
/**
* Adds {@code type} as a sub-field to the group configured by this builder.
*
* @return this builder for additional fields.
*/
public GroupBuilder addField(Type type) {
fields.add(type);
return this;
}
/**
* Adds {@code types} as sub-fields of the group configured by this builder.
*
* @return this builder for additional fields.
*/
public GroupBuilder
addFields(Type... types) {
for (Type type : types) {
fields.add(type);
}
return this;
}
@Override
protected GroupType build(String name) {
Preconditions.checkState(!fields.isEmpty(),
"Cannot build an empty group");
return new GroupType(repetition, name, originalType, fields);
}
}
public static class MessageTypeBuilder extends GroupBuilder {
private MessageTypeBuilder() {
super(MessageType.class);
repetition(Type.Repetition.REQUIRED);
}
/**
* Builds and returns the {@link MessageType} configured by this builder.
*
* Note: All primitive types and sub-groups should be added before
* calling this method.
*
* @param name a name for the constructed type
* @return the final {@code MessageType} configured by this builder.
*/
@Override
public MessageType named(String name) {
Preconditions.checkNotNull(name, "Name is required");
return new MessageType(name, fields);
}
}
/**
* Returns a builder to construct a {@link MessageType}.
*
* @return a {@link MessageTypeBuilder}
*/
public static MessageTypeBuilder buildMessage() {
return new MessageTypeBuilder();
}
public static GroupBuilder buildGroup(
Type.Repetition repetition) {
return new GroupBuilder(GroupType.class).repetition(repetition);
}
/**
* Returns a builder to construct a required {@link GroupType}.
*
* @return a {@link GroupBuilder}
*/
public static GroupBuilder requiredGroup() {
return new GroupBuilder(GroupType.class)
.repetition(Type.Repetition.REQUIRED);
}
/**
* Returns a builder to construct an optional {@link GroupType}.
*
* @return a {@link GroupBuilder}
*/
public static GroupBuilder optionalGroup() {
return new GroupBuilder(GroupType.class)
.repetition(Type.Repetition.OPTIONAL);
}
/**
* Returns a builder to construct a repeated {@link GroupType}.
*
* @return a {@link GroupBuilder}
*/
public static GroupBuilder repeatedGroup() {
return new GroupBuilder(GroupType.class)
.repetition(Type.Repetition.REPEATED);
}
public static PrimitiveBuilder primitive(
PrimitiveTypeName type, Type.Repetition repetition) {
return new PrimitiveBuilder(PrimitiveType.class, type)
.repetition(repetition);
}
/**
* Returns a builder to construct a required {@link PrimitiveType}.
*
* @param type a {@link PrimitiveTypeName} for the constructed type
* @return a {@link PrimitiveBuilder}
*/
public static PrimitiveBuilder required(
PrimitiveTypeName type) {
return new PrimitiveBuilder(PrimitiveType.class, type)
.repetition(Type.Repetition.REQUIRED);
}
/**
* Returns a builder to construct an optional {@link PrimitiveType}.
*
* @param type a {@link PrimitiveTypeName} for the constructed type
* @return a {@link PrimitiveBuilder}
*/
public static PrimitiveBuilder optional(
PrimitiveTypeName type) {
return new PrimitiveBuilder(PrimitiveType.class, type)
.repetition(Type.Repetition.OPTIONAL);
}
/**
* Returns a builder to construct a repeated {@link PrimitiveType}.
*
* @param type a {@link PrimitiveTypeName} for the constructed type
* @return a {@link PrimitiveBuilder}
*/
public static PrimitiveBuilder repeated(
PrimitiveTypeName type) {
return new PrimitiveBuilder(PrimitiveType.class, type)
.repetition(Type.Repetition.REPEATED);
}
}