/*
* Copyright © 2014 Cask Data, Inc.
*
* 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 co.cask.tigon.sql.flowlet;
import co.cask.tigon.sql.internal.DefaultGDATField;
import co.cask.tigon.sql.internal.DefaultStreamSchema;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import java.util.List;
import java.util.Set;
/**
* Used to define the Schema of a Input Stream to {@link AbstractInputFlowlet}.
*/
public interface StreamSchema {
List<GDATField> getFields();
/**
* Builder for creating instance of {@link StreamSchema}.
*/
static final class Builder {
private Set<String> fieldNames = Sets.newHashSet();
private List<GDATField> fields = Lists.newArrayList();
private void fieldCheck(String name) {
Preconditions.checkArgument(name != null, "Field name cannot be null.");
Preconditions.checkState(!fieldNames.contains(name), "Field name already used.");
}
public Builder addField(String name, GDATFieldType fieldType) {
fieldCheck(name);
this.fieldNames.add(name);
this.fields.add(new DefaultGDATField(name, fieldType));
return this;
}
public Builder addField(String name, GDATFieldType fieldType, GDATSlidingWindowAttribute windowAttribute) {
fieldCheck(name);
this.fieldNames.add(name);
this.fields.add(new DefaultGDATField(name, fieldType, windowAttribute));
return this;
}
public StreamSchema build() {
return new DefaultStreamSchema(fields);
}
}
}