Class SchemaTupleFactory

src/org/apache/pig/data/SchemaTupleFactory.java:32–129

This is an implementation of TupleFactory that will instantiate SchemaTuple's. This class has nothing to do with the actual generation of code, and instead simply encapsulates the classes which allow for efficiently creating SchemaTuples.

 * for efficiently creating SchemaTuples.
 */
public class SchemaTupleFactory implements TupleMaker<SchemaTuple<?>> {
    static final Log LOG = LogFactory.getLog(SchemaTupleFactory.class);

    private SchemaTupleQuickGenerator<? extends SchemaTuple<?>> generator;
    private Class<SchemaTuple<?>> clazz;
    private int tupleSize;

    protected SchemaTupleFactory(Class<SchemaTuple<?>> clazz,
            SchemaTupleQuickGenerator<? extends SchemaTuple<?>> generator) {
        this.clazz = clazz;
        this.generator = generator;
        tupleSize = generator.make().size();
    }

    /**
     * This method inspects a Schema to see whether or
     * not a SchemaTuple implementation can be generated
     * for the types present. Currently, bags and maps
     * are not supported.
     * @param   s as Schema
     * @return  boolean type value, true if it is generatable
     */
    public static boolean isGeneratable(Schema s) {
        if (s == null || s.size() == 0) {
            return false;
        }

        for (Schema.FieldSchema fs : s.getFields()) {
            if (fs.type == DataType.TUPLE && !isGeneratable(fs.schema)) {
                return false;
            }
        }

        return true;
    }

    @Override
    public SchemaTuple<?> newTuple() {
        return generator.make();
    }

    @Override
    public SchemaTuple<?> newTuple(int size) {
        if (size != tupleSize) {
            throw new RuntimeException("Request a SchemaTuple of the wrong size! Requested ["
                    + size + "], can only be [" + tupleSize + "]" );
        }
        return generator.make();
    }

    public Class<SchemaTuple<?>> tupleClass() {
        return clazz;
    }

    // We could make this faster by caching the result, but I doubt it will be called
    // in any great volume.
    public boolean isFixedSize() {
        return clazz.isAssignableFrom(AppendableSchemaTuple.class);