001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.beanutils;
018
019import java.beans.PropertyDescriptor;
020import java.util.Set;
021
022/**
023 * <p>
024 * A context interface used during introspection for querying and setting
025 * property descriptors.
026 * </p>
027 * <p>
028 * An implementation of this interface is passed to {@link BeanIntrospector}
029 * objects during processing of a bean class. It allows the
030 * {@code BeanIntrospector} to deliver descriptors for properties it has
031 * detected. It is also possible to find out which properties have already been
032 * found by another {@code BeanIntrospector}; this allows multiple
033 * {@code BeanIntrospector} instances to collaborate.
034 * </p>
035 *
036 * @version $Id$
037 * @since 1.9
038 */
039public interface IntrospectionContext {
040    /**
041     * Returns the class that is subject of introspection.
042     *
043     * @return the current class
044     */
045    Class<?> getTargetClass();
046
047    /**
048     * Adds the given property descriptor to this context. This method is called
049     * by a {@code BeanIntrospector} during introspection for each detected
050     * property. If this context already contains a descriptor for the affected
051     * property, it is overridden.
052     *
053     * @param desc the property descriptor
054     */
055    void addPropertyDescriptor(PropertyDescriptor desc);
056
057    /**
058     * Adds an array of property descriptors to this context. Using this method
059     * multiple descriptors can be added at once.
060     *
061     * @param descriptors the array of descriptors to be added
062     */
063    void addPropertyDescriptors(PropertyDescriptor[] descriptors);
064
065    /**
066     * Tests whether a descriptor for the property with the given name is
067     * already contained in this context. This method can be used for instance
068     * to prevent that an already existing property descriptor is overridden.
069     *
070     * @param name the name of the property in question
071     * @return <b>true</b> if a descriptor for this property has already been
072     *         added, <b>false</b> otherwise
073     */
074    boolean hasProperty(String name);
075
076    /**
077     * Returns the descriptor for the property with the given name or
078     * <b>null</b> if this property is unknown.
079     *
080     * @param name the name of the property in question
081     * @return the descriptor for this property or <b>null</b> if this property
082     *         is unknown
083     */
084    PropertyDescriptor getPropertyDescriptor(String name);
085
086    /**
087     * Removes the descriptor for the property with the given name.
088     *
089     * @param name the name of the affected property
090     */
091    void removePropertyDescriptor(String name);
092
093    /**
094     * Returns a set with the names of all properties known to this context.
095     *
096     * @return a set with the known property names
097     */
098    Set<String> propertyNames();
099}