io.delta.standalone.actions.Metadata Maven / Gradle / Ivy
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/*
* Copyright (2020-present) The Delta Lake Project 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 io.delta.standalone.actions;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import io.delta.standalone.types.StructType;
/**
* Updates the metadata of the table. The first version of a table must contain
* a {@link Metadata} action. Subsequent {@link Metadata} actions completely
* overwrite the current metadata of the table. It is the responsibility of the
* writer to ensure that any data already present in the table is still valid
* after any change. There can be at most one {@link Metadata} action in a
* given version of the table.
*
* @see Delta Transaction Log Protocol: Change Metadata
*/
public final class Metadata implements Action {
@Nonnull private final String id;
@Nullable private final String name;
@Nullable private final String description;
@Nonnull private final Format format;
@Nonnull private final List partitionColumns;
@Nonnull private final Map configuration;
@Nonnull private final Optional createdTime;
@Nullable private final StructType schema;
public Metadata(
@Nonnull String id,
@Nullable String name,
@Nullable String description,
@Nonnull Format format,
@Nonnull List partitionColumns,
@Nonnull Map configuration,
@Nonnull Optional createdTime,
@Nullable StructType schema) {
this.id = id;
this.name = name;
this.description = description;
this.format = format;
this.partitionColumns = partitionColumns;
this.configuration = configuration;
this.createdTime = createdTime;
this.schema = schema;
}
/**
* @return the unique identifier for this table
*/
@Nonnull
public String getId() {
return id;
}
/**
* @return the user-provided identifier for this table
*/
@Nullable
public String getName() {
return name;
}
/**
* @return the user-provided description for this table
*/
@Nullable
public String getDescription() {
return description;
}
/**
* @return the {@link Format} for this table
*/
@Nonnull
public Format getFormat() {
return format;
}
/**
* @return an unmodifiable {@code java.util.List} containing the names of
* columns by which the data should be partitioned
*/
@Nonnull
public List getPartitionColumns() {
return Collections.unmodifiableList(partitionColumns);
}
/**
* @return an unmodifiable {@code java.util.Map} containing configuration
* options for this metadata
*/
@Nonnull
public Map getConfiguration() {
return Collections.unmodifiableMap(configuration);
}
/**
* @return the time when this metadata action was created, in milliseconds
* since the Unix epoch
*/
@Nonnull
public Optional getCreatedTime() {
return createdTime;
}
/**
* @return the schema of the table as a {@link StructType}
*/
@Nullable
public StructType getSchema() {
return schema;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Metadata metadata = (Metadata) o;
return Objects.equals(id, metadata.id) &&
Objects.equals(name, metadata.name) &&
Objects.equals(description, metadata.description) &&
Objects.equals(format, metadata.format) &&
Objects.equals(partitionColumns, metadata.partitionColumns) &&
Objects.equals(configuration, metadata.configuration) &&
Objects.equals(createdTime, metadata.createdTime) &&
Objects.equals(schema, metadata.schema);
}
@Override
public int hashCode() {
return Objects.hash(id, name, description, format, partitionColumns, configuration,
createdTime, schema);
}
/**
* @return a new {@link Metadata.Builder} initialized with the same properties as this
* {@link Metadata} instance
*/
public Builder copyBuilder() {
return new Builder(id, name, description, format, partitionColumns, configuration,
createdTime, schema);
}
/**
* @return a new {@link Metadata.Builder}
*/
public static Builder builder() {
return new Builder();
}
/**
* Builder class for {@link Metadata}. Enables construction of {@link Metadata}s with default
* values.
*/
public static final class Builder {
@Nonnull private String id = java.util.UUID.randomUUID().toString();
@Nullable private String name;
@Nullable private String description;
@Nonnull private Format format = new Format("parquet", Collections.emptyMap());
@Nonnull private List partitionColumns = Collections.emptyList();
@Nonnull private Map configuration = Collections.emptyMap();
@Nonnull private Optional createdTime = Optional.of(System.currentTimeMillis());
@Nullable private StructType schema;
public Builder(){};
private Builder(
@Nonnull String id,
@Nullable String name,
@Nullable String description,
@Nonnull Format format,
@Nonnull List partitionColumns,
@Nonnull Map configuration,
@Nonnull Optional createdTime,
@Nullable StructType schema) {
this.id = id;
this.name = name;
this.description = description;
this.format = format;
this.partitionColumns = partitionColumns;
this.configuration = configuration;
this.createdTime = createdTime;
this.schema = schema;
}
public Builder id(@Nonnull String id) {
this.id = id;
return this;
}
public Builder name(@Nullable String name) {
this.name = name;
return this;
}
public Builder description(@Nullable String description) {
this.description = description;
return this;
}
public Builder format(@Nonnull Format format) {
this.format = format;
return this;
}
public Builder partitionColumns(@Nonnull List partitionColumns) {
this.partitionColumns = partitionColumns;
return this;
}
public Builder configuration(@Nonnull Map configuration) {
this.configuration = configuration;
return this;
}
public Builder createdTime(Long createdTime) {
this.createdTime = Optional.of(createdTime);
return this;
}
public Builder createdTime(@Nonnull Optional createdTime) {
this.createdTime = createdTime;
return this;
}
public Builder schema(@Nullable StructType schema) {
this.schema = schema;
return this;
}
/**
* Builds a {@link Metadata} using the provided parameters. If a parameter is not provided
* its default values is used.
*
* @return a new {@link Metadata} with the properties added to the builder
*/
public Metadata build() {
Metadata metadata = new Metadata(
this.id,
this.name,
this.description,
this.format,
this.partitionColumns,
this.configuration,
this.createdTime,
this.schema);
return metadata;
}
}
}