/**
* Copyright (C) 2009-2010 Wilfred Springer
*
* This file is part of Preon.
*
* Preon is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License as published by the Free Software
* Foundation; either version 2, or (at your option) any later version.
*
* Preon 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with
* Preon; see the file COPYING. If not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Linking this library statically or dynamically with other modules is making a
* combined work based on this library. Thus, the terms and conditions of the
* GNU General Public License cover the whole combination.
*
* As a special exception, the copyright holders of this library give you
* permission to link this library with independent modules to produce an
* executable, regardless of the license terms of these independent modules, and
* to copy and distribute the resulting executable under terms of your choice,
* provided that you also meet, for each linked independent module, the terms
* and conditions of the license of that module. An independent module is a
* module which is not derived from or based on this library. If you modify this
* library, you may extend this exception to your version of the library, but
* you are not obligated to do so. If you do not wish to do so, delete this
* exception statement from your version.
*/
package org.codehaus.preon.el.ctx;
import java.lang.reflect.Field;
import org.codehaus.preon.el.BindingException;
import org.codehaus.preon.el.Document;
import org.codehaus.preon.el.Expression;
import org.codehaus.preon.el.Expressions;
import org.codehaus.preon.el.InvalidExpressionException;
import org.codehaus.preon.el.Reference;
import org.codehaus.preon.el.ReferenceContext;
public class PropertyReference<T> implements Reference<T> {
private Field field;
private Reference<T> reference;
private ReferenceContext<T> context;
/**
* Include the type in the description generated.
*/
private boolean includeType = true;
public PropertyReference(Reference<T> reference, Class<?> type,
String name, ReferenceContext<T> context) {
this.reference = reference;
this.context = context;
try {
field = type.getDeclaredField(name);
field.setAccessible(true);
} catch (SecurityException e) {
throw new BindingException("Binding to " + name + " forbidden.");
} catch (NoSuchFieldException e) {
throw new BindingException("No field named " + name + ".");
}
}
private PropertyReference(Reference<T> reference, Field field, ReferenceContext<T> context) {
this.reference = reference;
this.field = field;
this.context = context;
}
public PropertyReference(Reference<T> reference, Class<?> type,
String name, ReferenceContext<T> context, boolean includeType) {
this(reference, type, name, context);
this.includeType = includeType;
}
public Object resolve(T context) {
try {
return field.get(reference.resolve(context));
} catch (IllegalArgumentException e) {
throw new BindingException("Cannot resolve " + field.getName()
+ " on context.", e);
} catch (IllegalAccessException e) {
throw new BindingException("Access denied for field "
+ field.getName(), e);
}
}
public Reference<T> selectAttribute(String name) {
return new PropertyReference<T>(this, this.getType(), name, context);
}
public Reference<T> selectItem(String index) {
try {
Expression<Integer, T> expr = Expressions.createInteger(context,
index);
return selectItem(expr);
} catch (InvalidExpressionException e) {
throw new BindingException("Invalid index.", e);
}
}
public Reference<T> selectItem(Expression<Integer, T> index) {
Class<?> type = this.field.getType();
return new ArrayElementReference<T>(this, type.getComponentType(), index,
context);
}
public Class<?> getType() {
return field.getType();
}
@SuppressWarnings("unchecked")
public boolean equals(Object other) {
if (other == null) {
return false;
} else if (other instanceof PropertyReference) {
return equals((PropertyReference<T>) other);
} else {
return false;
}
}
public boolean equals(PropertyReference<T> other) {
return field.equals(other.field) && reference.equals(other.reference);
}
public void document(Document target) {
target.text("the " + field.getName());
if (includeType) {
target.text(" (a ");
target.text(getType().getSimpleName());
target.text(") ");
} else {
target.text(" ");
}
target.text("of ");
reference.document(target);
}
public ReferenceContext<T> getReferenceContext() {
return context;
}
public boolean isAssignableTo(Class<?> type) {
return field.getType().isAssignableFrom(type);
}
public Reference<T> narrow(Class<?> type) {
if (field.getType().isAssignableFrom(type)) {
return this;
} else {
return null;
}
}
public boolean isBasedOn(ReferenceContext<T> context) {
return reference.isBasedOn(context);
}
public Reference<T> rescope(ReferenceContext<T> other) {
return new PropertyReference<T>(reference.rescope(other), field, this.context);
}
}