fullstack/hyracks/hyracks-dataflow-common/src/main/java/edu/uci/ics/hyracks/dataflow/common/comm/io/ArrayTupleBuilder.java

/*
 * Copyright 2009-2010 by The Regents of the University of California
 * 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 from
 * 
 *     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 edu.uci.ics.hyracks.dataflow.common.comm.io;

import java.io.DataOutput;
import java.io.IOException;

import edu.uci.ics.hyracks.api.comm.IFrameTupleAccessor;
import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider;
import edu.uci.ics.hyracks.data.std.util.GrowableArray;

/**
 * Array backed tuple builder.
 * 
 * @author vinayakb
 */
public class ArrayTupleBuilder implements IDataOutputProvider {
    private final GrowableArray fieldData = new GrowableArray();
    private final int[] fEndOffsets;
    private int nextField;

    public ArrayTupleBuilder(int nFields) {
        fEndOffsets = new int[nFields];
    }

    /**
     * Resets the builder.
     * reset() must be called before attempting to create a new tuple.
     */
    public void reset() {
        nextField = 0;
        fieldData.reset();
    }

    /**
     * Get the end offsets of the fields in this tuple.
     * 
     * @return end offsets of the fields.
     */
    public int[] getFieldEndOffsets() {
        return fEndOffsets;
    }

    /**
     * Get the data area in this builder.
     * 
     * @return Data byte array.
     */
    public byte[] getByteArray() {
        return fieldData.getByteArray();
    }

    /**
     * Get the size of the data area.
     * 
     * @return data area size.
     */
    public int getSize() {
        return fieldData.getLength();
    }

    /**
     * Add a field to the tuple from a field in a frame.
     * 
     * @param accessor
     *            - Frame that contains the field to be copied into the tuple
     *            builder.
     * @param tIndex
     *            - Tuple index of the tuple that contains the field to be
     *            copied.
     * @param fIndex
     *            - Field index of the field to be copied.
     * @throws HyracksDataException
     */
    public void addField(IFrameTupleAccessor accessor, int tIndex, int fIndex) throws HyracksDataException {
        int startOffset = accessor.getTupleStartOffset(tIndex);
        int fStartOffset = accessor.getFieldStartOffset(tIndex, fIndex);
        int fLen = accessor.getFieldEndOffset(tIndex, fIndex) - fStartOffset;
        try {
            fieldData.getDataOutput().write(accessor.getBuffer().array(),
                    startOffset + accessor.getFieldSlotsLength() + fStartOffset, fLen);
            if (FrameConstants.DEBUG_FRAME_IO) {
                fieldData.getDataOutput().writeInt(FrameConstants.FRAME_FIELD_MAGIC);
            }
        } catch (IOException e) {
            throw new HyracksDataException(e);
        }
        fEndOffsets[nextField++] = fieldData.getLength();
    }

    /**
     * Add a field to the tuple by serializing the given object using the given
     * serializer.
     * 
     * @param serDeser
     *            - Serializer
     * @param instance
     *            - Object to serialize
     * @throws HyracksDataException
     */
    public <T> void addField(ISerializerDeserializer<T> serDeser, T instance) throws HyracksDataException {
        serDeser.serialize(instance, fieldData.getDataOutput());
        fEndOffsets[nextField++] = fieldData.getLength();
    }

    /**
     * Add a field to the tuple by copying the data bytes from a byte array.
     * 
     * @param bytes
     *            - Byte array to copy the field data from.
     * @param start
     *            - Start offset of the field to be copied in the byte array.
     * @param length
     *            - Length of the field to be copied.
     * @throws HyracksDataException
     */
    public void addField(byte[] bytes, int start, int length) throws HyracksDataException {
        try {
            fieldData.getDataOutput().write(bytes, start, length);
        } catch (IOException e) {
            throw new HyracksDataException(e);
        }
        fEndOffsets[nextField++] = fieldData.getLength();
    }

    /**
     * Get the {@link DataOutput} interface to write into the tuple builder.
     */
    @Override
    public DataOutput getDataOutput() {
        return fieldData.getDataOutput();
    }

    /**
     * Get the growable array storing the field data.
     */
    public GrowableArray getFieldData() {
        return fieldData;
    }

    /**
     * Sets the byte offset of the end of the field into the field offset array.
     * Make sure this method is called when the {@link DataOutput} interface is
     * used to add field data into the tuple, at the end of adding a field's
     * data.
     */
    public void addFieldEndOffset() {
        fEndOffsets[nextField++] = fieldData.getLength();
    }
}