/*
* ElementMap.java August 2007
*
* Copyright (C) 2007, Niall Gallagher <niallg@users.sf.net>
*
* 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 org.simpleframework.xml;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Retention;
/**
* The <code>ElementMap</code> annotation represents a method or field
* that is a <code>Map</code> for storing key value pairs. The map
* object deserialized is typically of the same type as the field.
* However, a <code>class</code> attribute can be used to override the
* field type, however the type must be assignable.
* <pre>
*
* <map class="java.util.HashMap">
* <entry key="one">value one</entry>
* <entry key="two">value two</entry>
* <entry key="three">value three</entry>
* </map>
*
* </pre>
* If a <code>class</code> attribute is not provided and the type or
* the field or method is abstract, a suitable match is searched for
* from the maps available from the Java collections framework. This
* annotation can support both primitive and composite values and
* keys enabling just about any configuration to be used.
* <pre>
*
* <map class="java.util.HashMap">
* <entry key="1">
* <value>value one</value>
* </entry>
* <entry key="2">
* <value>value two</value>
* </entry>
* <entry key="3">
* <value>value three</value>
* </entry>
* </map>
*
* </pre>
* The above XML is an example of the output for an composite value
* object. Composite and primitive values can be used without any
* specified attributes, in such a case names for primitives are the
* names of the objects they represent. Also, if desired these
* default names can be overridden using the provided attributes
* making the resulting XML entirely configurable.
*
* @author Niall Gallagher
*/
@Retention(RetentionPolicy.RUNTIME)
public @interface ElementMap {
/**
* This represents the name of the XML element. Annotated fields
* can optionally provide the name of the element. If no name is
* provided then the name of the annotated field or method will
* be used in its place. The name is provided if the field or
* method name is not suitable as an XML element name. Also, if
* the list is inline then this must not be specified.
*
* @return the name of the XML element this represents
*/
String name() default "";
/**
* This is used to provide a the name of the entry XML element
* that wraps the key and value elements. If specified the entry
* value specified will be used instead of the default name of
* the element. This is used to ensure the resulting XML is
* configurable to the requirements of the generated XML.
*
* @return this returns the entry XML element for each entry
*/
String entry() default "";
/**
* This is used to provide a value XML element for each of the
* values within the map. This essentially wraps the entity to
* be serialized such that there is an extra XML element present.
* This can be used to override the default names of primitive
* values, however it can also be used to wrap composite values.
*
* @return this returns the value XML element for each value
*/
String value() default "";
/**
* This is used to provide a key XML element for each of the
* keys within the map. This essentially wraps the entity to
* be serialized such that there is an extra XML element present.
* This can be used to override the default names of primitive
* keys, however it can also be used to wrap composite keys.
*
* @return this returns the key XML element for each key
*/
String key() default "";
/**
* Represents the type of key the element map contains. This
* type is used to deserialize the XML entry key from the map.
* The object typically represents the deserialized type, but can
* represent a subclass of the type deserialized as determined
* by the <code>class</code> attribute value for the map. If
* this is not specified then the type can be determined from the
* generic parameter of the annotated <code>Map</code> object.
*
* @return the type of the entry key deserialized from the XML
*/
Class keyType() default void.class;
/**
* Represents the type of value the element map contains. This
* type is used to deserialize the XML entry value from the map.
* The object typically represents the deserialized type, but can
* represent a subclass of the type deserialized as determined
* by the <code>class</code> attribute value for the map. If
* this is not specified then the type can be determined from the
* generic parameter of the annotated <code>Map</code> object.
*
* @return the type of the entry value deserialized from the XML
*/
Class valueType() default void.class;
/**
* Represents whether the key value is to be an attribute or an
* element. This allows the key to be embedded within the entry
* XML element allowing for a more compact representation. Only
* primitive key objects can be represented as an attribute. For
* example a <code>java.util.Date</code> or a string could be
* represented as an attribute key for the generated XML.
*
* @return true if the key is to be inlined as an attribute
*/
boolean attribute() default false;
/**
* Determines whether the element is required within the XML
* document. Any field marked as not required will not have its
* value set when the object is deserialized. If an object is to
* be serialized only a null attribute will not appear as XML.
*
* @return true if the element is required, false otherwise
*/
boolean required() default true;
/**
* This is used to determine whether the element data is written
* in a CDATA block or not. If this is set to true then the text
* is written within a CDATA block, by default the text is output
* as escaped XML. Typically this is useful when this annotation
* is applied to an array of primitives, such as strings.
*
* @return true if entries are to be wrapped in a CDATA block
*/
boolean data() default false;
/**
* Determines whether the element list is inlined with respect
* to the parent XML element. An inlined element list does not
* contain an enclosing element. It is simple a sequence of
* elements that appear one after another within an element.
* As such an inline element list must not have a name.
*
* @return this returns true if the element list is inline
*/
boolean inline() default false;
/**
* This is used to determine if an optional field or method can
* remain null if it does not exist. If this is false then the
* optional element is given an empty map. This is a convenience
* attribute which avoids having to check if the element is null
* before providing it with a suitable default instance.
*
* @return false if an optional element is always instantiated
*/
boolean empty() default true;
}