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/*
* TextListLabel.java December 2012
*
* Copyright (C) 2012, Niall Gallagher
*
* 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.core;
import java.lang.annotation.Annotation;
import org.simpleframework.xml.Text;
import org.simpleframework.xml.strategy.Type;
/**
* The TextListLabel object is used to create a label
* that will create a converter used to read free text. Free text is
* text that exists between elements. An ElementListUnion
* can be declared to consume text that exists between the individual
* elements by declaring a Text annotation with it. In
* such a declaration unstructured text can be processed.
*
* @author Niall Gallagher
*
* @see org.simpleframework.xml.core.GroupExtractor
*/
class TextListLabel extends TemplateLabel {
/**
* This is the empty value that is declared for the annotation.
*/
private final String empty;
/**
* This is the element list union label that is declared with this.
*/
private final Label label;
/**
* This is the text annotation declaration on the element list.
*/
private final Text text;
/**
* Constructor for the TextListLabel object. This is
* used to create a label used for reading free text declared
* between the elements of an element list union. Such a label
* enables serialization and deserialization of unstructured XML.
*
* @param label this is the label that is declared with this
* @param text this is the text annotation delcaration
*/
public TextListLabel(Label label, Text text) {
this.empty = text.empty();
this.label = label;
this.text = text;
}
/**
* This is used to acquire the Decorator for this.
* A decorator is an object that adds various details to the
* node without changing the overall structure of the node. For
* example comments and namespaces can be added to the node with
* a decorator as they do not affect the deserialization.
*
* @return this returns the decorator associated with this
*/
public Decorator getDecorator() throws Exception {
return null;
}
/**
* This returns a Collection of element names. This
* will typically contain both the name and path of the label.
* However, if this is a union it can contain many names and
* paths. This method should never return null.
*
* @return this returns the names of each of the elements
*/
public String[] getNames() throws Exception {
return label.getNames();
}
/**
* This returns a Collection of element paths. This
* will typically contain only the path of the label, which is
* composed using the Path annotation and the name
* of the label. However, if this is a union it can contain many
* paths. This method should never return null.
*
* @return this returns the names of each of the elements
*/
public String[] getPaths() throws Exception {
return label.getPaths();
}
/**
* This is used to provide a configured empty value used when the
* annotated value is null. This ensures that XML can be created
* with required details regardless of whether values are null or
* not. It also provides a means for sensible default values.
*
* @param context this is the context object for the serialization
*
* @return this returns the string to use for default values
*/
public String getEmpty(Context context) throws Exception {
return empty;
}
/**
* This method returns a Converter which can be used to
* convert an XML node into an object value and vice versa. The
* converter requires only the context object in order to perform
* serialization or deserialization of the provided XML node.
*
* @param context this is the context object for the serialization
*
* @return this returns an object that is used for conversion
*/
public Converter getConverter(Context context) throws Exception {
Type type = getContact();
if(!label.isCollection()) {
throw new TextException("Cannot use %s to represent %s", type, label);
}
return new TextList(context, type, label);
}
/**
* This is used to acquire the name of the element or attribute
* that is used by the class schema. The name is determined by
* checking for an override within the annotation. If it contains
* a name then that is used, if however the annotation does not
* specify a name the the field or method name is used instead.
*
* @return returns the name that is used for the XML property
*/
public String getName() throws Exception {
return label.getName();
}
/**
* This is used to acquire the path of the element or attribute
* that is used by the class schema. The path is determined by
* acquiring the XPath expression and appending the name of the
* label to form a fully qualified path.
*
* @return returns the path that is used for the XML property
*/
public String getPath() throws Exception {
return label.getPath();
}
/**
* This method is used to return an XPath expression that is
* used to represent the position of this label. If there is no
* XPath expression associated with this then an empty path is
* returned. This will never return a null expression.
*
* @return the XPath expression identifying the location
*/
public Expression getExpression() throws Exception {
return label.getExpression();
}
/**
* This is used to acquire the dependent class for this label.
* This returns null as there are no dependents to the element
* annotation as it can only hold primitives with no dependents.
*
* @return this is used to return the dependent type of null
*/
public Type getDependent() throws Exception {
return label.getDependent();
}
/**
* This is typically used to acquire the entry value as acquired
* from the annotation. However given that the annotation this
* represents does not have a entry attribute this will always
* provide a null value for the entry string.
*
* @return this will always return null for the entry value
*/
public String getEntry() throws Exception {
return label.getEntry();
}
/**
* This is the key used to represent this label. The key is used
* to store the parameter in hash containers. Typically the
* key is generated from the paths associated with the label.
*
* @return this is the key used to represent the label
*/
public Object getKey() throws Exception {
return label.getKey();
}
/**
* This acquires the annotation associated with this label. This
* is typically the annotation acquired from the field or method.
* However, in the case of unions this will return the actual
* annotation within the union group that this represents.
*
* @return this returns the annotation that this represents
*/
public Annotation getAnnotation() {
return label.getAnnotation();
}
/**
* This is used to acquire the contact object for this label. The
* contact retrieved can be used to set any object or primitive that
* has been deserialized, and can also be used to acquire values to
* be serialized in the case of object persistence. All contacts
* that are retrieved from this method will be accessible.
*
* @return returns the field that this label is representing
*/
public Contact getContact() {
return label.getContact();
}
/**
* This acts as a convenience method used to determine the type of
* the field this represents. This is used when an object is written
* to XML. It determines whether a class attribute
* is required within the serialized XML element, that is, if the
* class returned by this is different from the actual value of the
* object to be serialized then that type needs to be remembered.
*
* @return this returns the type of the field class
*/
public Class getType() {
return label.getType();
}
/**
* This is used to acquire the name of the element or attribute
* as taken from the annotation. If the element or attribute
* explicitly specifies a name then that name is used for the
* XML element or attribute used. If however no overriding name
* is provided then the method or field is used for the name.
*
* @return returns the name of the annotation for the contact
*/
public String getOverride() {
return label.getOverride();
}
/**
* This is used to determine whether the annotation requires it
* and its children to be written as a CDATA block. This is done
* when a primitive or other such element requires a text value
* and that value needs to be encapsulated within a CDATA block.
*
* @return this returns true if the element requires CDATA
*/
public boolean isData() {
return label.isData();
}
/**
* Determines whether the XML attribute or element is required.
* This ensures that if an XML element is missing from a document
* that deserialization can continue. Also, in the process of
* serialization, if a value is null it does not need to be
* written to the resulting XML document.
*
* @return true if the label represents a some required data
*/
public boolean isRequired() {
return label.isRequired();
}
/**
* This is used to determine if the label is a collection. If the
* label represents a collection then any original assignment to
* the field or method can be written to without the need to
* create a new collection. This allows obscure collections to be
* used and also allows initial entries to be maintained.
*
* @return true if the label represents a collection value
*/
public boolean isCollection() {
return true;
}
/**
* This is used to determine whether the label represents an
* inline XML entity. The ElementList annotation
* and the Text annotation represent inline
* items. This means that they contain no containing element
* and so can not specify overrides or special attributes.
*
* @return this returns true if the annotation is inline
*/
public boolean isInline() {
return label.isInline();
}
/**
* This is used to determine if an annotated list is a text
* list. A text list is a list of elements that also accepts
* free text. Typically this will be an element list union that
* will allow unstructured XML such as XHTML to be parsed.
*
* @return returns true if the label represents a text list
*/
public boolean isTextList() {
return true;
}
/**
* This is used to create a string used to represent this text
* list label. This will basically create a string representing
* the other label in addition to the Text label.
*
* @return this is used to build a string for the list label
*/
public String toString() {
return String.format("%s %s", text, label);
}
}