src/main/java/org/apache/bsf/util/ScriptSymbolTable.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.bsf.util;

import java.util.Hashtable;

/**
 * An <code>ScriptSymbolTable</code> object is used by a <code>CodeBuffer</code>
 * object to implement nested scopes.
 * 
 * @author   Matthew J. Duftler
 */
class ScriptSymbolTable extends Hashtable
{
    private final Hashtable parentTable;

    ScriptSymbolTable(final Hashtable parentTable)
  {
    this.parentTable = parentTable;
  }
  public synchronized Object get(final Object key)
  {
    Object ret = super.get(key);

    if (ret == null && parentTable != null) {
        ret = parentTable.get(key);
    }

    return ret;
  }
}