/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.deltaspike.data.impl.property.query;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import org.apache.deltaspike.data.impl.property.MethodProperty;
import org.apache.deltaspike.data.impl.property.Properties;
import org.apache.deltaspike.data.impl.property.Property;
/**
* <p>
* Queries a target class for properties that match certain criteria. A property may either be a private or public
* field, declared by the target class or inherited from a superclass, or a public method declared by the target class
* or inherited from any of its superclasses. For properties that are exposed via a method, the property must be a
* JavaBean style property, i.e. it must provide both an accessor and mutator method according to the JavaBean
* specification.
* </p>
* <p/>
* <p>
* This class is not thread-safe, however the result returned by the getResultList() method is.
* </p>
*
* @see PropertyQueries
* @see PropertyCriteria
*/
public class PropertyQuery<V>
{
private final Class<?> targetClass;
private final List<PropertyCriteria> criteria;
PropertyQuery(Class<?> targetClass)
{
if (targetClass == null)
{
throw new IllegalArgumentException("targetClass parameter may not be null");
}
this.targetClass = targetClass;
this.criteria = new ArrayList<PropertyCriteria>();
}
/**
* Add a criteria to query
*
* @param criteria
* the criteria to add
*/
public PropertyQuery<V> addCriteria(PropertyCriteria criteria)
{
this.criteria.add(criteria);
return this;
}
/**
* Get the first result from the query, causing the query to be run.
*
* @return the first result, or null if there are no results
*/
public Property<V> getFirstResult()
{
List<Property<V>> results = getResultList();
return results.isEmpty() ? null : results.get(0);
}
/**
* Get the first result from the query that is not marked as read only, causing the query to be run.
*
* @return the first writable result, or null if there are no results
*/
public Property<V> getFirstWritableResult()
{
List<Property<V>> results = getWritableResultList();
return results.isEmpty() ? null : results.get(0);
}
/**
* Get a single result from the query, causing the query to be run. An exception is thrown if the query does not
* return exactly one result.
*
* @return the single result
* @throws RuntimeException
* if the query does not return exactly one result
*/
public Property<V> getSingleResult()
{
List<Property<V>> results = getResultList();
if (results.size() == 1)
{
return results.get(0);
}
else if (results.isEmpty())
{
throw new RuntimeException("Expected one property match, but the criteria did not match any properties on "
+ targetClass.getName());
}
else
{
throw new RuntimeException("Expected one property match, but the criteria matched " + results.size()
+ " properties on " + targetClass.getName());
}
}
/**
* Get a single result from the query that is not marked as read only, causing the query to be run. An exception is
* thrown if the query does not return exactly one result.
*
* @return the single writable result
* @throws RuntimeException
* if the query does not return exactly one result
*/
public Property<V> getWritableSingleResult()
{
List<Property<V>> results = getWritableResultList();
if (results.size() == 1)
{
return results.get(0);
}
else if (results.isEmpty())
{
throw new RuntimeException("Expected one property match, but the criteria did not match any properties on "
+ targetClass.getName());
}
else
{
throw new RuntimeException("Expected one property match, but the criteria matched " + results.size()
+ " properties on " + targetClass.getName());
}
}
/**
* Get the result from the query, causing the query to be run.
*
* @return the results, or an empty list if there are no results
*/
public List<Property<V>> getResultList()
{
return getResultList(false);
}
/**
* Get the non read only results from the query, causing the query to be run.
*
* @return the results, or an empty list if there are no results
*/
public List<Property<V>> getWritableResultList()
{
return getResultList(true);
}
/**
* Get the result from the query, causing the query to be run.
*
* @param writable
* if this query should only return properties that are not read only
* @return the results, or an empty list if there are no results
*/
private List<Property<V>> getResultList(boolean writable)
{
List<Property<V>> results = new ArrayList<Property<V>>();
// First check public accessor methods (we ignore private methods)
for (Method method : targetClass.getMethods())
{
if (!(method.getName().startsWith("is") || method.getName().startsWith("get")))
{
continue;
}
boolean match = true;
for (PropertyCriteria c : criteria)
{
if (!c.methodMatches(method))
{
match = false;
break;
}
}
if (match)
{
MethodProperty<V> property = Properties.<V> createProperty(method);
if (!writable || !property.isReadOnly())
{
results.add(property);
}
}
}
Class<?> cls = targetClass;
while (cls != null && !cls.equals(Object.class))
{
// Now check declared fields
for (Field field : cls.getDeclaredFields())
{
boolean match = true;
for (PropertyCriteria c : criteria)
{
if (!c.fieldMatches(field))
{
match = false;
break;
}
}
Property<V> prop = Properties.<V> createProperty(field);
if (match && !resultsContainsProperty(results, prop.getName()))
{
if (!writable || !prop.isReadOnly())
{
results.add(prop);
}
}
}
cls = cls.getSuperclass();
}
return results;
}
private boolean resultsContainsProperty(List<Property<V>> results, String propertyName)
{
for (Property<V> p : results)
{
if (propertyName.equals(p.getName()))
{
return true;
}
}
return false;
}
}