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.
 */
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;
    }
}