*/
    boolean getExists() throws ResourceException;

    /**
     * Returns true when the content of this resource is empty. This method is may be more efficient than calling {@link #getText()} and checking the length.
     *
     * <p>Note that this method may be expensive when {@link #isContentCached()} returns false, depending on the implementation.
     *

import java.io.InputStream;
import java.util.Map;

import org.codelibs.fess.crawler.entity.ExtractData;

/**
 * @author shinsuke
 *
 */
public interface Extractor {

    ExtractData getText(InputStream in, Map<String, String> params);

    }

    public void test_addExtractor() {
        final ExtractorFactory extractorFactory = new ExtractorFactory();
        final Extractor extractor = new Extractor() {
            public ExtractData getText(final InputStream in, final Map<String, String> params) {
                return null;
            }
        };

        assertNull(extractorFactory.getExtractor("test"));

    }

    @Override
    SourceElement getSources() {
        return empty()
    }

    @Override
    public void writeToProject(TestFile projectDir) {
        getMain().writeToProject(projectDir);
        getTest().writeToProject(projectDir);
    }

  @CollectionFeature.Require(SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedPresent() {
    assertFalse("add(present) should return false", getSet().add(e0()));
    expectUnchanged();
  }

  @CollectionFeature.Require(value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedNullPresent() {

            && PatternMatchers.ANY_EXPRESSION.equals(id.getType())
            && PatternMatchers.ANY_EXPRESSION.equals(id.getExt())) {
            return null;
        }
        return new DefaultIvyArtifactName(id.getName(), id.getType(), id.getExt());
    }

    // TODO We should get rid of this reflection (will need to reimplement the parser to act on the metadata directly)

        final Map<String, String> params = new HashMap<String, String>();
        //final ExtractData text = extractor.getText(new ByteArrayInputStream(FileUtils.readFileToByteArray(new File(filePath))), params);
        final ExtractData text = extractor.getText(new ByteArrayInputStream(testStr.getBytes()), params);
        assertEquals(content, text.getContent());
    }

    // TODO other tests

      expectedHashCode += ((element == null) ? 0 : element.hashCode());
    }
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements.",
        expectedHashCode,
        getSet().hashCode());
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testHashCode_containingNull() {

            interface Pet {
                String getName()
                void setName(String name)
            }

            @Managed
            interface Person {
                Pet getPet()
            }

            class RulePlugin extends RuleSource {
                @Model
                void person(Person person) {
                }

                @Mutate

/**
 * @author shinsuke
 *
 */
public class TextExtractor extends AbstractExtractor {

    protected String encoding = Constants.UTF_8;

    @Override
    public ExtractData getText(final InputStream in, final Map<String, String> params) {
        if (in == null) {
            throw new CrawlerSystemException("The inputstream is null.");
        }
        try {