Java tutorial
/* * 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.prestosql.orc.stream; import com.google.common.collect.ImmutableMap; import io.prestosql.orc.StreamDescriptor; import io.prestosql.orc.StreamId; import io.prestosql.orc.metadata.Stream.StreamKind; import java.util.Map; import static com.google.common.base.Preconditions.checkArgument; import static io.prestosql.orc.stream.MissingInputStreamSource.missingStreamSource; import static java.util.Objects.requireNonNull; public class InputStreamSources { private final Map<StreamId, InputStreamSource<?>> streamSources; public InputStreamSources(Map<StreamId, InputStreamSource<?>> streamSources) { this.streamSources = ImmutableMap.copyOf(requireNonNull(streamSources, "streamSources is null")); } public <S extends ValueInputStream<?>> InputStreamSource<S> getInputStreamSource( StreamDescriptor streamDescriptor, StreamKind streamKind, Class<S> streamType) { requireNonNull(streamDescriptor, "streamDescriptor is null"); requireNonNull(streamType, "streamType is null"); InputStreamSource<?> streamSource = streamSources .get(new StreamId(streamDescriptor.getStreamId(), streamDescriptor.getSequence(), streamKind)); if (streamSource == null) { streamSource = missingStreamSource(streamType); } checkArgument(streamType.isAssignableFrom(streamSource.getStreamType()), "%s must be of type %s, not %s", streamDescriptor, streamType.getName(), streamSource.getStreamType().getName()); return (InputStreamSource<S>) streamSource; } }