ObjectContext.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;

/**
 * Wraps an Object as a Jexl context.
 * @param <T> the wrapped object type to use
 * @since 2.1
 */
public class ObjectContext<T> implements JexlContext {
    /** The property solving jexl engine. */
    private final JexlEngine jexl;
    /** The object serving as context provider. */
    private final T object;

    /**
     * Creates a new ObjectContext.
     * @param engine the jexl engine to use to solve properties
     * @param wrapped the object to wrap in this context
     */
    public ObjectContext(JexlEngine engine, T wrapped) {
        this.jexl = engine;
        this.object = wrapped;
    }

    /** {@inheritDoc} */
    public Object get(String name) {
        return jexl.getProperty(object, name);
    }

    /** {@inheritDoc} */
    public void set(String name, Object value) {
        jexl.setProperty(object, name, value);
    }

    /** {@inheritDoc} */
    public boolean has(String name) {
        return jexl.getUberspect().getPropertyGet(object, name, null) != null;
    }

    /** {@inheritDoc} */
    public void remove(String name) {
        jexl.setProperty(object, name, null);
    }

    /** {@inheritDoc} */
    @Override
    public JexlContext copy() {
        Class c = object.getClass();
        try {
            Object o = c.newInstance();
            return new ObjectContext<>(jexl,o);
        }catch (Exception e){
        }
        return null;
    }

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