ReadonlyContext.java

/**
 * Copyright 2016 Nabarun Mondal
 * 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 com.noga.njexl.lang;

/**
 * A readonly context wrapper.
 * @since 2.1
 */
public final class ReadonlyContext implements JexlContext {
    /** The wrapped context. */
    private final JexlContext wrapped;

    /**
     * Creates a new readonly context.
     * @param context the wrapped context
     */
    public ReadonlyContext(JexlContext context) {
        wrapped = context;
    }

    /** {@inheritDoc} */
    public Object get(String name) {
        return wrapped.get(name);
    }

    /** 
     * Will throw an UnsupportedOperationException when called; the JexlEngine deals with it appropriately.
     * @param name the unused variable name
     * @param value the unused variable value
     */
    public void set(String name, Object value) {
        throw new UnsupportedOperationException("Not supported.");
    }

    public void remove(String name) {
        throw new UnsupportedOperationException("Not supported.");
    }

    /** {@inheritDoc} */
    public boolean has(String name) {
        return wrapped.has(name);
    }

    /** {@inheritDoc} */
    @Override
    public JexlContext copy() {
        return this;
    }

    /** {@inheritDoc} */
    public void clear() {
        throw new UnsupportedOperationException("not supported!");
    }
}