com.mysema.query.Tuple Maven / Gradle / Ivy
/*
* Copyright 2011, Mysema Ltd
*
* 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 com.mysema.query;
import javax.annotation.Nullable;
import com.mysema.query.types.Expression;
/**
* Tuple defines an interface for generic query result projection
*
* Usage example:
*
* {@code
* List result = query.from(employee).list(new QTuple(employee.firstName, employee.lastName));
* for (Tuple row : result) {
* System.out.println("firstName " + row.get(employee.firstName));
* System.out.println("lastName " + row.get(employee.lastName));
* }
* }
*
*
* @author tiwe
*
*/
public interface Tuple {
/**
* Get a Tuple element by index
*
* @param
* @param index
* @param type
* @return
*/
@Nullable
T get(int index, Class type);
/**
* Get a tuple element by expression
*
* @param
* @param expr
* @return
*/
@Nullable
T get(Expression expr);
/**
* Get the size of the Tuple
*
* @return
*/
int size();
/**
* Get the content as an Object array
*
* @return
*/
Object[] toArray();
/**
* All Tuples should override equals and hashCode. For compatibility
* across different Tuple implementations, equality check should use
* {@link java.util.Arrays#equals(Object[], Object[])} with {@link #toArray()} as parameters.
*
* @see Object#equals(Object)
*/
boolean equals(Object o);
/**
* All Tuples should override equals and hashCode. For compatibility
* across different Tuple implementations, hashCode should use
* {@link java.util.Arrays#hashCode(Object[])} with {@link #toArray()} as parameter.
*
* @see Object#hashCode()
*/
int hashCode();
}