/*
* Copyright 2013-2014 the original author or authors.
*
* 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.springframework.data.mongodb.core.aggregation;
import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
import org.springframework.util.Assert;
import com.mongodb.DBObject;
/**
* {@link AggregationOperationContext} that combines the available field references from a given
* {@code AggregationOperationContext} and an {@link FieldsExposingAggregationOperation}.
*
* @author Thomas Darimont
* @author Oliver Gierke
* @since 1.4
*/
class ExposedFieldsAggregationOperationContext implements AggregationOperationContext {
private final ExposedFields exposedFields;
private final AggregationOperationContext rootContext;
/**
* Creates a new {@link ExposedFieldsAggregationOperationContext} from the given {@link ExposedFields}. Uses the given
* {@link AggregationOperationContext} to perform a mapping to mongo types if necessary.
*
* @param exposedFields must not be {@literal null}.
* @param rootContext must not be {@literal null}.
*/
public ExposedFieldsAggregationOperationContext(ExposedFields exposedFields, AggregationOperationContext rootContext) {
Assert.notNull(exposedFields, "ExposedFields must not be null!");
Assert.notNull(rootContext, "RootContext must not be null!");
this.exposedFields = exposedFields;
this.rootContext = rootContext;
}
/*
* (non-Javadoc)
* @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getMappedObject(com.mongodb.DBObject)
*/
@Override
public DBObject getMappedObject(DBObject dbObject) {
return rootContext.getMappedObject(dbObject);
}
/*
* (non-Javadoc)
* @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(org.springframework.data.mongodb.core.aggregation.ExposedFields.AvailableField)
*/
@Override
public FieldReference getReference(Field field) {
return getReference(field, field.getTarget());
}
/*
* (non-Javadoc)
* @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(java.lang.String)
*/
@Override
public FieldReference getReference(String name) {
return getReference(null, name);
}
/**
* Returns a {@link FieldReference} to the given {@link Field} with the given {@code name}.
*
* @param field may be {@literal null}
* @param name must not be {@literal null}
* @return
*/
private FieldReference getReference(Field field, String name) {
Assert.notNull(name, "Name must not be null!");
ExposedField exposedField = exposedFields.getField(name);
if (exposedField != null) {
if (field != null) {
// we return a FieldReference to the given field directly to make sure that we reference the proper alias here.
return new FieldReference(new ExposedField(field, exposedField.isSynthetic()));
}
return new FieldReference(exposedField);
}
if (name.contains(".")) {
// for nested field references we only check that the root field exists.
ExposedField rootField = exposedFields.getField(name.split("\\.")[0]);
if (rootField != null) {
// We have to synthetic to true, in order to render the field-name as is.
return new FieldReference(new ExposedField(name, true));
}
}
throw new IllegalArgumentException(String.format("Invalid reference '%s'!", name));
}
}