com.hazelcast.projection.Projections Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2018, Hazelcast, Inc. All Rights Reserved.
*
* 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.hazelcast.projection;
import com.hazelcast.projection.impl.IdentityProjection;
import com.hazelcast.projection.impl.MultiAttributeProjection;
import com.hazelcast.projection.impl.SingleAttributeProjection;
/**
* A utility class to create basic {@link com.hazelcast.projection.Projection} instances.
*
* @since 3.8
*/
public final class Projections {
private Projections() {
}
/**
* Returns a projection that does no transformation.
*
* If you use the returned projection in a 3.9 cluster it may cause a serialization exception.
*
* @since 3.10
*/
public static Projection identity() {
return (IdentityProjection) IdentityProjection.INSTANCE;
}
/**
* Returns a projection that extracts the value of the given {@code attributePath}.
*
* @param attributePath single attribute path, path must not be null or empty
* @param Output type
*/
public static Projection singleAttribute(String attributePath) {
return new SingleAttributeProjection(attributePath);
}
/**
* Returns a projection that extracts the value of the given {@code attributePaths}.
* The attribute values will be returned as an {@code Object[]} array from each projection call.
*
* @param attributePaths attribute paths, paths must not be null or empty
*/
public static Projection multiAttribute(String... attributePaths) {
return new MultiAttributeProjection(attributePaths);
}
}