/*
* 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.api.common.io;
import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.api.common.functions.RuntimeContext;
import org.apache.flink.api.common.io.statistics.BaseStatistics;
import org.apache.flink.api.common.operators.base.InnerJoinOperatorBase;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.core.io.InputSplit;
import org.apache.flink.core.io.InputSplitAssigner;
import java.io.IOException;
/**
* A ReplicatingInputFormat replicates any {@link InputFormat} to all parallel instances of a DataSource,
* i.e., the full input of the replicated InputFormat is completely processed by each parallel instance of the DataSource.
* This is done by assigning all {@link org.apache.flink.core.io.InputSplit}s generated by the
* replicated InputFormat to each parallel instance.
*
* Replicated data can only be used as input for a {@link InnerJoinOperatorBase} or
* {@link org.apache.flink.api.common.operators.base.CrossOperatorBase} with the same parallelism as the DataSource.
* Before being used as an input to a Join or Cross operator, replicated data might be processed in local pipelines by
* by Map-based operators with the same parallelism as the source. Map-based operators are
* {@link org.apache.flink.api.common.operators.base.MapOperatorBase},
* {@link org.apache.flink.api.common.operators.base.FlatMapOperatorBase},
* {@link org.apache.flink.api.common.operators.base.FilterOperatorBase}, and
* {@link org.apache.flink.api.common.operators.base.MapPartitionOperatorBase}.
*
* Replicated DataSources can be used for local join processing (no data shipping) if one input is accessible on all
* parallel instance of a join and the other input is (randomly) partitioned across all parallel instances.
*
* However, a replicated DataSource is a plan hint that can invalidate a Flink program if not used correctly (see
* usage instructions above). In such situations, the optimizer is not able to generate a valid execution plan and
* the program execution will fail.
*
* @param <OT> The output type of the wrapped InputFormat.
* @param <S> The InputSplit type of the wrapped InputFormat.
*
* @see org.apache.flink.api.common.io.InputFormat
* @see org.apache.flink.api.common.io.RichInputFormat
* @see InnerJoinOperatorBase
* @see org.apache.flink.api.common.operators.base.CrossOperatorBase
* @see org.apache.flink.api.common.operators.base.MapOperatorBase
* @see org.apache.flink.api.common.operators.base.FlatMapOperatorBase
* @see org.apache.flink.api.common.operators.base.FilterOperatorBase
* @see org.apache.flink.api.common.operators.base.MapPartitionOperatorBase
*/
@PublicEvolving
public final class ReplicatingInputFormat<OT, S extends InputSplit> extends RichInputFormat<OT, S> {
private static final long serialVersionUID = 1L;
private InputFormat<OT, S> replicatedIF;
public ReplicatingInputFormat(InputFormat<OT, S> wrappedIF) {
this.replicatedIF = wrappedIF;
}
public InputFormat<OT, S> getReplicatedInputFormat() {
return this.replicatedIF;
}
@Override
public void configure(Configuration parameters) {
this.replicatedIF.configure(parameters);
}
@Override
public BaseStatistics getStatistics(BaseStatistics cachedStatistics) throws IOException {
return this.replicatedIF.getStatistics(cachedStatistics);
}
@Override
public S[] createInputSplits(int minNumSplits) throws IOException {
return this.replicatedIF.createInputSplits(minNumSplits);
}
@Override
public InputSplitAssigner getInputSplitAssigner(S[] inputSplits) {
return new ReplicatingInputSplitAssigner(inputSplits);
}
@Override
public void open(S split) throws IOException {
this.replicatedIF.open(split);
}
@Override
public boolean reachedEnd() throws IOException {
return this.replicatedIF.reachedEnd();
}
@Override
public OT nextRecord(OT reuse) throws IOException {
return this.replicatedIF.nextRecord(reuse);
}
@Override
public void close() throws IOException {
this.replicatedIF.close();
}
@Override
public void setRuntimeContext(RuntimeContext context) {
if (this.replicatedIF instanceof RichInputFormat) {
((RichInputFormat)this.replicatedIF).setRuntimeContext(context);
}
}
@Override
public RuntimeContext getRuntimeContext(){
if (this.replicatedIF instanceof RichInputFormat) {
return ((RichInputFormat)this.replicatedIF).getRuntimeContext();
} else{
throw new RuntimeException("The underlying input format to this ReplicatingInputFormat isn't context aware");
}
}
@Override
public void openInputFormat() throws IOException {
if (this.replicatedIF instanceof RichInputFormat) {
((RichInputFormat)this.replicatedIF).openInputFormat();
}
}
@Override
public void closeInputFormat() throws IOException {
if (this.replicatedIF instanceof RichInputFormat) {
((RichInputFormat)this.replicatedIF).closeInputFormat();
}
}
}