io.druid.segment.data.CompressedFloatsSupplierSerializer.java Source code

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Here is the source code for io.druid.segment.data.CompressedFloatsSupplierSerializer.java

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/*
 * Druid - a distributed column store.
 * Copyright 2012 - 2015 Metamarkets Group 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 io.druid.segment.data;

import com.google.common.io.ByteStreams;
import com.google.common.io.OutputSupplier;
import com.google.common.primitives.Ints;
import io.druid.collections.ResourceHolder;
import io.druid.collections.StupidResourceHolder;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;

/**
 */
public class CompressedFloatsSupplierSerializer {
    public static CompressedFloatsSupplierSerializer create(IOPeon ioPeon, final String filenameBase,
            final ByteOrder order, final CompressedObjectStrategy.CompressionStrategy compression)
            throws IOException {
        return create(ioPeon, filenameBase, CompressedFloatsIndexedSupplier.MAX_FLOATS_IN_BUFFER, order,
                compression);
    }

    public static CompressedFloatsSupplierSerializer create(IOPeon ioPeon, final String filenameBase,
            final int sizePer, final ByteOrder order,
            final CompressedObjectStrategy.CompressionStrategy compression) throws IOException {
        final CompressedFloatsSupplierSerializer retVal = new CompressedFloatsSupplierSerializer(sizePer,
                new GenericIndexedWriter<ResourceHolder<FloatBuffer>>(ioPeon, filenameBase,
                        CompressedFloatBufferObjectStrategy.getBufferForOrder(order, compression, sizePer)),
                compression);
        return retVal;
    }

    private final int sizePer;
    private final GenericIndexedWriter<ResourceHolder<FloatBuffer>> flattener;
    private final CompressedObjectStrategy.CompressionStrategy compression;

    private int numInserted = 0;

    private FloatBuffer endBuffer;

    public CompressedFloatsSupplierSerializer(int sizePer,
            GenericIndexedWriter<ResourceHolder<FloatBuffer>> flattener,
            CompressedObjectStrategy.CompressionStrategy compression) {
        this.sizePer = sizePer;
        this.flattener = flattener;
        this.compression = compression;

        endBuffer = FloatBuffer.allocate(sizePer);
        endBuffer.mark();
    }

    public void open() throws IOException {
        flattener.open();
    }

    public int size() {
        return numInserted;
    }

    public void add(float value) throws IOException {
        if (!endBuffer.hasRemaining()) {
            endBuffer.rewind();
            flattener.write(StupidResourceHolder.create(endBuffer));
            endBuffer = FloatBuffer.allocate(sizePer);
            endBuffer.mark();
        }

        endBuffer.put(value);
        ++numInserted;
    }

    public void closeAndConsolidate(OutputSupplier<? extends OutputStream> consolidatedOut) throws IOException {
        endBuffer.limit(endBuffer.position());
        endBuffer.rewind();
        flattener.write(StupidResourceHolder.create(endBuffer));
        endBuffer = null;

        flattener.close();

        try (OutputStream out = consolidatedOut.getOutput()) {
            out.write(CompressedFloatsIndexedSupplier.version);
            out.write(Ints.toByteArray(numInserted));
            out.write(Ints.toByteArray(sizePer));
            out.write(new byte[] { compression.getId() });
            ByteStreams.copy(flattener.combineStreams(), out);
        }
    }
}