001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005// http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.commons.services;
014
015import java.lang.reflect.Field;
016import java.lang.reflect.Method;
017
018import org.apache.tapestry5.commons.AnnotationProvider;
019
020/**
021 * Provides access to a single property within a class. Acts as an {@link org.apache.tapestry5.commons.AnnotationProvider};
022 * when searching for annotations, the read method (if present) is checked first, followed by the write method, followed
023 * by the underlying field (when the property name matches the field name).
024 *
025 * Starting in release 5.2, this property may actually be a public field. In 5.3, it may be a public static field.
026 *
027 * @see org.apache.tapestry5.commons.services.ClassPropertyAdapter
028 */
029public interface PropertyAdapter extends AnnotationProvider
030{
031    /**
032     * Returns the name of the property (or public field).
033     */
034    String getName();
035
036    /**
037     * Returns true if the property is readable (i.e., has a getter method or is a public field).
038     */
039    boolean isRead();
040
041    /**
042     * Returns the method used to read the property, or null if the property is not readable (or is a public field).
043     */
044    public Method getReadMethod();
045
046    /**
047     * Returns true if the property is writeable (i.e., has a setter method or is a non-final field).
048     */
049    boolean isUpdate();
050
051    /**
052     * Returns the method used to update the property, or null if the property is not writeable (or a public field).
053     */
054    public Method getWriteMethod();
055
056    /**
057     * Reads the property value.
058     *
059     * @param instance to read from
060     * @throws UnsupportedOperationException if the property is write only
061     */
062    Object get(Object instance);
063
064    /**
065     * Updates the property value. The provided value must not be null if the property type is primitive, and must
066     * otherwise be of the proper type.
067     *
068     * @param instance to update
069     * @param value    new value for the property
070     * @throws UnsupportedOperationException if the property is read only
071     */
072    void set(Object instance, Object value);
073
074    /**
075     * Returns the type of the property.
076     */
077    Class getType();
078
079    /**
080     * Returns true if the return type of the read method is not the same as the property type. This can occur when the
081     * property has been defined using generics, in which case, the method's type may be Object when the property type
082     * is something more specific. This method is primarily used when generating runtime code related to the property.
083     */
084    boolean isCastRequired();
085
086    /**
087     * Returns the {@link org.apache.tapestry5.commons.services.ClassPropertyAdapter} that provides access to other
088     * properties defined by the same class.
089     */
090    ClassPropertyAdapter getClassAdapter();
091
092    /**
093     * Returns the type of bean to which this property belongs. This is the same as
094     * {@link org.apache.tapestry5.commons.services.ClassPropertyAdapter#getBeanType()}.
095     */
096    Class getBeanType();
097
098    /**
099     * Returns true if the property is actually a public field (possibly, a public static field).
100     *
101     * @since 5.2
102     */
103    boolean isField();
104
105    /**
106     * Returns the field if the property is a public field or null if the property is accessed via the read method.
107     *
108     * @since 5.2
109     */
110    Field getField();
111
112    /**
113     * The class in which the property (or public field) is defined.
114     *
115     * @since 5.2
116     */
117    Class getDeclaringClass();
118}