| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.flink.table.api.java |
| |
| import org.apache.flink.table.api.{TumbleWithSize, OverWindowWithPreceding, SlideWithSize, SessionWithGap} |
| import org.apache.flink.table.expressions.{Expression, ExpressionParser} |
| |
| /** |
| * Helper class for creating a tumbling window. Tumbling windows are consecutive, non-overlapping |
| * windows of a specified fixed length. For example, a tumbling window of 5 minutes size groups |
| * elements in 5 minutes intervals. |
| */ |
| object Tumble { |
| |
| /** |
| * Creates a tumbling window. Tumbling windows are consecutive, non-overlapping |
| * windows of a specified fixed length. For example, a tumbling window of 5 minutes size groups |
| * elements in 5 minutes intervals. |
| * |
| * @param size the size of the window as time or row-count interval. |
| * @return a partially defined tumbling window |
| */ |
| def over(size: String): TumbleWithSize = new TumbleWithSize(size) |
| } |
| |
| /** |
| * Helper class for creating a sliding window. Sliding windows have a fixed size and slide by |
| * a specified slide interval. If the slide interval is smaller than the window size, sliding |
| * windows are overlapping. Thus, an element can be assigned to multiple windows. |
| * |
| * For example, a sliding window of size 15 minutes with 5 minutes sliding interval groups elements |
| * of 15 minutes and evaluates every five minutes. Each element is contained in three consecutive |
| * window evaluations. |
| */ |
| object Slide { |
| |
| /** |
| * Creates a sliding window. Sliding windows have a fixed size and slide by |
| * a specified slide interval. If the slide interval is smaller than the window size, sliding |
| * windows are overlapping. Thus, an element can be assigned to multiple windows. |
| * |
| * For example, a sliding window of size 15 minutes with 5 minutes sliding interval groups |
| * elements of 15 minutes and evaluates every five minutes. Each element is contained in three |
| * consecutive window evaluations. |
| * |
| * @param size the size of the window as time or row-count interval |
| * @return a partially specified sliding window |
| */ |
| def over(size: String): SlideWithSize = new SlideWithSize(size) |
| } |
| |
| /** |
| * Helper class for creating a session window. The boundary of session windows are defined by |
| * intervals of inactivity, i.e., a session window is closes if no event appears for a defined |
| * gap period. |
| */ |
| object Session { |
| |
| /** |
| * Creates a session window. The boundary of session windows are defined by |
| * intervals of inactivity, i.e., a session window is closes if no event appears for a defined |
| * gap period. |
| * |
| * @param gap specifies how long (as interval of milliseconds) to wait for new data before |
| * closing the session window. |
| * @return a partially defined session window |
| */ |
| def withGap(gap: String): SessionWithGap = new SessionWithGap(gap) |
| } |
| |
| /** |
| * Helper object for creating a over window. |
| */ |
| object Over { |
| |
| /** |
| * Specifies the time attribute on which rows are grouped. |
| * |
| * For streaming tables call [[orderBy 'rowtime or orderBy 'proctime]] to specify time mode. |
| * |
| * For batch tables, refer to a timestamp or long attribute. |
| */ |
| def orderBy(orderBy: String): OverWindowWithOrderBy = { |
| val orderByExpr = ExpressionParser.parseExpressionList(orderBy).toArray |
| new OverWindowWithOrderBy(Array[Expression](), orderByExpr) |
| } |
| |
| /** |
| * Partitions the elements on some partition keys. |
| * |
| * @param partitionBy some partition keys. |
| * @return A partitionedOver instance that only contains the orderBy method. |
| */ |
| def partitionBy(partitionBy: String): PartitionedOver = { |
| val partitionByExpr = ExpressionParser.parseExpressionList(partitionBy).toArray |
| new PartitionedOver(partitionByExpr) |
| } |
| } |
| |
| class PartitionedOver(private val partitionByExpr: Array[Expression]) { |
| |
| /** |
| * Specifies the time attribute on which rows are grouped. |
| * |
| * For streaming tables call [[orderBy 'rowtime or orderBy 'proctime]] to specify time mode. |
| * |
| * For batch tables, refer to a timestamp or long attribute. |
| */ |
| def orderBy(orderBy: String): OverWindowWithOrderBy = { |
| val orderByExpr = ExpressionParser.parseExpressionList(orderBy).toArray |
| new OverWindowWithOrderBy(partitionByExpr, orderByExpr) |
| } |
| } |
| |
| |
| class OverWindowWithOrderBy( |
| private val partitionByExpr: Array[Expression], |
| private val orderByExpr: Array[Expression]) { |
| |
| /** |
| * Set the preceding offset (based on time or row-count intervals) for over window. |
| * |
| * @param preceding preceding offset relative to the current row. |
| * @return this over window |
| */ |
| def preceding(preceding: String): OverWindowWithPreceding = { |
| val precedingExpr = ExpressionParser.parseExpression(preceding) |
| new OverWindowWithPreceding(partitionByExpr, orderByExpr, precedingExpr) |
| } |
| |
| } |