org.simpleframework.xml.core.VersionLabel Maven / Gradle / Ivy
/*
* VersionLabel.java July 2008
*
* Copyright (C) 2008, Niall Gallagher
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA
*/
package org.simpleframework.xml.core;
import org.simpleframework.xml.Version;
import org.simpleframework.xml.stream.Style;
/**
* The VersionLabel object is used convert any double
* retrieved from an XML attribute to a version revision. The version
* is used to determine how to perform serialization of a composite
* by determining version compatibility.
*
* @author Niall Gallagher
*/
class VersionLabel implements Label {
/**
* This is the decorator that is associated with the attribute.
*/
private Decorator decorator;
/**
* This contains the details of the annotated contact object.
*/
private Signature detail;
/**
* Represents the annotation used to label the field.
*/
private Version label;
/**
* This is the type that the field object references.
*/
private Class type;
/**
* This is the name of the element for this label instance.
*/
private String name;
/**
* Constructor for the VersionLabel object. This is
* used to create a label that can convert from a double to an
* XML attribute and vice versa. This requires the annotation and
* contact extracted from the XML schema class.
*
* @param contact this is the field from the XML schema class
* @param label represents the annotation for the field
*/
public VersionLabel(Contact contact, Version label) {
this.detail = new Signature(contact, this);
this.decorator = new Qualifier(contact);
this.type = contact.getType();
this.name = label.name();
this.label = label;
}
/**
* 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 decorator;
}
/**
* Creates a Converter that can convert an attribute
* to a double value. This requires the context object used for
* the current instance of XML serialization being performed.
*
* @param context this is context object used for serialization
*
* @return this returns the converted for this attribute object
*/
public Converter getConverter(Context context) throws Exception {
String ignore = getEmpty(context);
if(!context.isFloat(type)) {
throw new AttributeException("Cannot use %s to represent %s", label, type);
}
return new Primitive(context, type, ignore);
}
/**
* 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) {
return null;
}
/**
* 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.
*
* @param context the context object used to style the name
*
* @return returns the name that is used for the XML property
*/
public String getName(Context context) throws Exception {
Style style = context.getStyle();
String name = detail.getName();
return style.getAttribute(name);
}
/**
* 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 detail.getName();
}
/**
* 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 name;
}
/**
* 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 persistance. All contacts
* that are retrieved from this method will be accessible.
*
* @return returns the contact that this label is representing
*/
public Contact getContact() {
return detail.getContact();
}
/**
* This acts as a convenience method used to determine the type of
* the contact this represents. This will be a primitive type of a
* primitive type from the java.lang primitives.
*
* @return this returns the type of the contact class
*/
public Class getType() {
return type;
}
/**
* 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() {
return null;
}
/**
* This is used to acquire the dependent class for this label.
* This returns null as there are no dependents to the attribute
* annotation as it can only hold primitives with no dependents.
*
* @return this is used to return the dependent type of null
*/
public Class getDependent() {
return null;
}
/**
* This method is used to determine if the label represents an
* attribute. This is used to style the name so that elements
* are styled as elements and attributes are styled as required.
*
* @return this is used to determine if this is an attribute
*/
public boolean isAttribute() {
return true;
}
/**
* 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 false;
}
/**
* This is used to determine whether the attribute is required.
* This ensures that if an attribute 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.required();
}
/**
* Because the attribute can contain only simple text values it
* is never required to specified as anything other than text.
* Therefore this will always return false as CDATA does not
* apply to the attribute values.
*
* @return this will always return false for XML attributes
*/
public boolean isData() {
return false;
}
/**
* This method is used by the deserialization process to check
* to see if an annotation is inline or not. If an annotation
* represents an inline XML entity then the deserialization
* and serialization process ignores overrides and special
* attributes. By default all attributes are not inline items.
*
* @return this always returns false for attribute labels
*/
public boolean isInline() {
return false;
}
/**
* This is used to describe the annotation and method or field
* that this label represents. This is used to provide error
* messages that can be used to debug issues that occur when
* processing a method. This will provide enough information
* such that the problem can be isolated correctly.
*
* @return this returns a string representation of the label
*/
public String toString() {
return detail.toString();
}
}