thredds.catalog.crawl

Class CatalogCrawler

java.lang.Object

thredds.catalog.crawl.CatalogCrawler

public class CatalogCrawler
extends Object

This crawls a catalog tree for its datasets, which are sent to a listener. You can get all or some of the datasets. A "direct" dataset is one which hasAccess() is true, meaning it has one or more access elements.

Example use:

 CatalogCrawler.Listener listener = new CatalogCrawler.Listener() {
   public void getDataset(InvDataset dd) {
     if (dd.isHarvest())
       doHarvest(dd);
   }
 };
 CatalogCrawler crawler = new CatalogCrawler( CatalogCrawler.USE_ALL_DIRECT, false, listener);
 

Author:

John Caron

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	CatalogCrawler.Filter
static interface	CatalogCrawler.Listener
static class	CatalogCrawler.Type

Field Summary

Fields

Modifier and Type	Field and Description
static int	USE_ALL
static int	USE_ALL_DIRECT
static int	USE_FIRST_DIRECT
static int	USE_RANDOM_DIRECT
static int	USE_RANDOM_DIRECT_NOT_FIRST_OR_LAST

Constructor Summary

Constructors

Constructor and Description
CatalogCrawler(CatalogCrawler.Type type, CatalogCrawler.Filter filter, CatalogCrawler.Listener listen) Constructor.
CatalogCrawler(int type, boolean skipDatasetScan, CatalogCrawler.Listener listen) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
int	crawl(InvCatalogImpl cat, CancelTask task, PrintWriter out, Object context) Crawl a catalog thats already been opened.
int	crawl(String catUrl, CancelTask task, PrintWriter out, Object context) Open a catalog and crawl (depth first) all the datasets in it.
void	crawlDataset(InvDataset ds, CancelTask task, PrintWriter out, Object context, boolean release) Crawl this dataset recursively, return all datasets
void	crawlDirectDatasets(InvDataset ds, CancelTask task, PrintWriter out, Object context, boolean release) Crawl this dataset recursively.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

USE_ALL

public static final int USE_ALL

See Also:

Constant Field Values

USE_ALL_DIRECT

public static final int USE_ALL_DIRECT

See Also:

Constant Field Values

USE_FIRST_DIRECT

public static final int USE_FIRST_DIRECT

See Also:

Constant Field Values

USE_RANDOM_DIRECT

public static final int USE_RANDOM_DIRECT

See Also:

Constant Field Values

USE_RANDOM_DIRECT_NOT_FIRST_OR_LAST

public static final int USE_RANDOM_DIRECT_NOT_FIRST_OR_LAST

See Also:

Constant Field Values

Constructor Detail

CatalogCrawler

public CatalogCrawler(int type,
              boolean skipDatasetScan,
              CatalogCrawler.Listener listen)

Constructor.

Parameters:

type - CatalogCrawler.USE_XXX constant: When you get to a dataset containing leaf datasets, do all, only the first, or a randomly chosen one.

skipDatasetScan - if true, dont recurse into DatasetScan elements. This is useful if you are looking only for collection level metadata.

listen - this is called for each dataset.

CatalogCrawler

public CatalogCrawler(CatalogCrawler.Type type,
              CatalogCrawler.Filter filter,
              CatalogCrawler.Listener listen)

Constructor.

Parameters:

type - CatalogCrawler.Type

filter - dont process this dataset or its descendants. may be null

listen - each dataset gets passed to the listener

Method Detail

crawl

public int crawl(String catUrl,
        CancelTask task,
        PrintWriter out,
        Object context)

Open a catalog and crawl (depth first) all the datasets in it. Close catalogs and release their resources as you.

Parameters:

catUrl - url of catalog to open

task - user can cancel the task (may be null)

out - send status messages to here (may be null)

context - caller can pass this object in (used for thread safety)

Returns:

number of catalog references opened and crawled

crawl

public int crawl(InvCatalogImpl cat,
        CancelTask task,
        PrintWriter out,
        Object context)

Crawl a catalog thats already been opened. When you get to a dataset containing leaf datasets, do all, only the first, or a randomly chosen one.

Parameters:

cat - the catalog

task - user can cancel the task (may be null)

out - send status messages to here (may be null)

context - caller can pass this object in (used for thread safety)

Returns:

number of catalog references opened and crawled

crawlDataset

public void crawlDataset(InvDataset ds,
                CancelTask task,
                PrintWriter out,
                Object context,
                boolean release)

Crawl this dataset recursively, return all datasets

Parameters:

ds - the dataset

task - user can cancel the task (may be null)

out - send status messages to here (may be null)

context - caller can pass this object in (used for thread safety)

crawlDirectDatasets

public void crawlDirectDatasets(InvDataset ds,
                       CancelTask task,
                       PrintWriter out,
                       Object context,
                       boolean release)

Crawl this dataset recursively. Only send back direct datasets

Parameters:

ds - the dataset

task - user can cancel the task (may be null)

out - send status messages to here (may be null)

context - caller can pass this object in (used for thread safety)