java/javax/el/BeanNameResolver.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 javax.el;

/**
 * Base implementation that provides a minimal default implementation that is
 * intended to be extended by application developers.
 *
 * @since EL 3.0
 */
public abstract class BeanNameResolver {

    /**
     * Can this resolver resolve the given bean name?
     *
     * @param beanName The bean name to resolve
     *
     * @return This default implementation always returns <code>false</code>
     */
    public boolean isNameResolved(String beanName) {
        return false;
    }


    /**
     * Returns the named bean.
     *
     * @param beanName The bean name to return
     *
     * @return This default implementation always returns <code>null</code>
     */
    public Object getBean(String beanName) {
        return null;
    }


    /**
     * Sets a value of a bean of the given name. If the named bean does not
     * exist and {@link #canCreateBean} returns <code>true</code> then a bean
     * is created with the given value.
     *
     * @param beanName The name of the bean to be set/create
     * @param value    The value of the bean to set/create
     *
     * @throws PropertyNotWritableException if the bean is read only
     */
    public void setBeanValue(String beanName, Object value)
            throws PropertyNotWritableException {
        throw new PropertyNotWritableException();
    }


    /**
     * Is the named bean read-only?
     *
     * @param beanName The name of the bean of interest
     *
     * @return <code>true</code> if the bean is read only, otherwise
     *         <code>false</code>
     */
    public boolean isReadOnly(String beanName) {
        return true;
    }


    /**
     * Is it permitted to create a bean of the given name?
     *
     * @param beanName The name of the bean of interest
     *
     * @return <code>true</code> if the bean may be created, otherwise
     *         <code>false</code>
     */
    public boolean canCreateBean(String beanName) {
        return false;
    }
}