ValueTableReference.java

/*
 * Copyright (c) 2017 OBiBa. All rights reserved.
 *
 * This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.obiba.magma.support;

import org.obiba.magma.MagmaEngine;
import org.obiba.magma.NoSuchDatasourceException;
import org.obiba.magma.NoSuchValueTableException;
import org.obiba.magma.ValueTable;

/**
 * Extends {@link AbstractValueTableWrapper} and uses {@link MagmaEngine} to lookup the referenced {@link ValueTable}
 * instance.
 */
@SuppressWarnings("UnusedDeclaration")
public class ValueTableReference extends AbstractValueTableWrapper {

  /**
   * Fully-qualified {@link ValueTable} reference.
   */
  private String reference;

  /**
   * Cached {@link MagmaEngineTableResolver}
   */
  @SuppressWarnings("TransientFieldInNonSerializableClass")
  private transient MagmaEngineTableResolver tableResolver;

  /**
   * No-arg constructor for XStream.
   */
  public ValueTableReference() {

  }

  /**
   * {@link ValueTableReference} constructor.
   * <p/>
   * Note: The constructor creates an instance so long as the specified reference is well-formed (even if no such table
   *
   * @param reference fully-qualified value table reference
   * @throws IllegalArgumentException if the reference is not well-formed
   */
  public ValueTableReference(String reference) {
    if(reference == null) throw new IllegalArgumentException("reference cannot be null");
    this.reference = reference;
    getResolver();
  }

  @Override
  public ValueTable getWrappedValueTable() {
    try {
      return getResolver().resolveTable();
    } catch(NoSuchValueTableException e) {
      // OPAL-1231
      return NullValueTable.get();
    } catch(NoSuchDatasourceException e) {
      // OPAL-1231
      return NullValueTable.get();
    }
  }

  public String getReference() {
    return reference;
  }

  protected MagmaEngineTableResolver getResolver() {
    if(tableResolver == null) {
      tableResolver = MagmaEngineTableResolver.valueOf(reference);
    }
    return tableResolver;
  }

}