001/*
002 *  Copyright 2001-2013 Stephen Colebourne
003 *
004 *  Licensed under the Apache License, Version 2.0 (the "License");
005 *  you may not use this file except in compliance with the License.
006 *  You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 *  Unless required by applicable law or agreed to in writing, software
011 *  distributed under the License is distributed on an "AS IS" BASIS,
012 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 *  See the License for the specific language governing permissions and
014 *  limitations under the License.
015 */
016package org.joda.beans;
017
018import java.util.Map;
019import java.util.NoSuchElementException;
020
021/**
022 * A meta-bean, defining those aspects of a bean which are not specific
023 * to a particular instance, such as the type and set of meta-properties.
024 * 
025 * @author Stephen Colebourne
026 */
027public interface MetaBean {
028
029    /**
030     * Creates a bean builder that can be used to create an instance of this bean.
031     * 
032     * @return the bean builder, not null
033     * @throws UnsupportedOperationException if the bean cannot be created
034     */
035    BeanBuilder<? extends Bean> builder();
036
037    /**
038     * Creates a map of properties for the specified bean.
039     * 
040     * @param bean  the bean to create the map for, not null
041     * @return the created property map, not null
042     */
043    PropertyMap createPropertyMap(Bean bean);
044
045    //-----------------------------------------------------------------------
046    /**
047     * Gets the bean name, which is normally the fully qualified class name of the bean.
048     * 
049     * @return the name of the bean, not empty
050     */
051    String beanName();
052
053    /**
054     * Get the type of the bean represented as a {@code Class}.
055     * 
056     * @return the type of the bean, not null
057     */
058    Class<? extends Bean> beanType();
059
060    //-----------------------------------------------------------------------
061    /**
062     * Counts the number of properties.
063     * 
064     * @return the number of properties
065     */
066    int metaPropertyCount();
067
068    /**
069     * Checks if a property exists.
070     * 
071     * @param propertyName  the property name to check, null returns false
072     * @return true if the property exists
073     */
074    boolean metaPropertyExists(String propertyName);
075
076    /**
077     * Gets a meta-property by name.
078     * 
079     * @param <R>  the property type, optional, enabling auto-casting
080     * @param propertyName  the property name to retrieve, null throws NoSuchElementException
081     * @return the meta property, not null
082     * @throws NoSuchElementException if the property name is invalid
083     */
084    <R> MetaProperty<R> metaProperty(String propertyName);
085
086    /**
087     * Gets an iterator of meta-properties.
088     * <p>
089     * This method returns an {@code Iterable}, which is simpler than a {@code Map}.
090     * As a result, implementations may be able to optimise, and so this method should be
091     * preferred to {@link #metaPropertyMap()} where a choice is possible.
092     * 
093     * @return the unmodifiable map of meta property objects, not null
094     */
095    Iterable<MetaProperty<?>> metaPropertyIterable();
096
097    /**
098     * Gets the map of meta-properties, keyed by property name.
099     * <p>
100     * Where possible, use {@link #metaPropertyIterable()} instead.
101     * 
102     * @return the unmodifiable map of meta property objects, not null
103     */
104    Map<String, MetaProperty<?>> metaPropertyMap();
105
106}