Metacat

/*

 * Copyright 2006 Google 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 org.kepler.web.client;

import com.google.gwt.core.client.GWT;

import com.google.gwt.user.client.Command;

import com.google.gwt.user.client.DeferredCommand;

import com.google.gwt.user.client.rpc.AsyncCallback;

import com.google.gwt.user.client.rpc.ServiceDefTarget;

import com.google.gwt.user.client.ui.Composite;

public class MetacatResultsWidget extends Composite {

  private final MetacatProvider metacatProvider = new MetacatProvider();

  private final DynaTableWidget dynaTable;

  private Command pendingRefresh;

  private boolean queryPerformed = false;

  private String lastSearch = null;

  public class MetacatProvider implements DynaTableDataProvider {

    public MetacatProvider() {

      // Initialize the service.

      //

      keplerService = (KeplerServiceAsync) GWT.create(KeplerService.class);

      // By default, we assume we'll make RPCs to a servlet, but see

      // updateRowData(). There is special support for canned RPC responses.

      // (Which is a totally demo hack, by the way :-)

      //

      ServiceDefTarget target = (ServiceDefTarget) keplerService;

      // Use a module-relative URLs to ensure that this client code can find

      // its way home, even when the URL changes (as might happen when you

      // deploy this as a webapp under an external servlet container).

      moduleRelativeURL = "http://library.kepler-project.org/kepler/gwt";

    }

    public void updateRowData(final int startRow, final int maxRows,

        final RowDataAcceptor acceptor, String searchTerm)

    {

      // Check the simple cache first.

      if(searchTerm == null)

      {

        searchTerm = "%";

      }

      if(queryPerformed && lastSearch.trim().equals(searchTerm.trim()))

      {

          // Use the cached batch.

          pushResults(acceptor, startRow, maxRows, lastResult);

          return;

      }

      else

      {

        lastSearch = searchTerm;

      }

      /*keplerService.login("uid=kepler,o=unaffiliated,dc=ecoinformatics,dc=org",

        new AsyncCallback() {

          public void onFailure(Throwable caught) {

          acceptor.failed(caught);

        }

        public void onSuccess(Object result) {

          //handle successful login

        }

      });*/

      //do the query

      if(searchTerm == null)

      {

        lastSearch = "%";

      }

      keplerService.query(lastSearch, "", new AsyncCallback() {

        public void onFailure(Throwable caught) {

          acceptor.failed(caught);

        }

        public void onSuccess(Object result) {

          //handle successful query

          MetacatQueryResult[] queryResult = (MetacatQueryResult[])result;

          lastStartRow = startRow;

          lastMaxRows = maxRows;

          lastResult = queryResult;

          queryPerformed = true;

          dynaTable.setMaxRowCount(queryResult.length);

          pushResults(acceptor, startRow, maxRows, queryResult);

        }

      });

    }

    private void pushResults(RowDataAcceptor acceptor, int startRow,

        int maxRows, MetacatQueryResult[] queryResults) {

      int offset = (queryResults.length - 0) - startRow;

      if(offset > maxRows)

      {

        offset = maxRows;

      }

      String[][] rows = new String[offset][];

      for (int i = 0; i < offset; i++) {

        MetacatQueryResult result = queryResults[startRow + i];

        rows[i] = new String[3];

        rows[i][0] = " ";

        rows[i][1] = result.getName();

        rows[i][2] = result.getDocid();

      }

      acceptor.accept(startRow, rows);

    }

    private final KeplerServiceAsync keplerService;

    private int lastMaxRows = -1;

    private MetacatQueryResult[] lastResult;

    private int lastStartRow = -1;

  }

  public MetacatResultsWidget(int visibleRows) {

    String[] columns = new String[]{"", "Name", "DocId"};

    String[] styles = new String[]{"", "name", "docid"};

    dynaTable = new DynaTableWidget(metacatProvider, columns, styles, visibleRows);

    initWidget(dynaTable);

  }

  protected void onLoad() {

    dynaTable.refresh();

  }

}