QueryDslFetchJoin.java

package com.thinkbiganalytics.metadata.jpa.support;

/*-
 * #%L
 * thinkbig-operational-metadata-jpa
 * %%
 * Copyright (C) 2017 ThinkBig Analytics
 * %%
 * 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.
 * #L%
 */

import com.querydsl.core.types.EntityPath;

/**
 * Helper class to add joins to a QueryDsl query
 */
public class QueryDslFetchJoin {

    public final EntityPath joinPath;
    public final EntityPath alias;
    public final Join type;

    private QueryDslFetchJoin(EntityPath joinPath, Join type) {
        this.joinPath = joinPath;
        this.alias = null;
        this.type = type;
    }

    private QueryDslFetchJoin(EntityPath joinPath, EntityPath alias, Join type) {
        this.joinPath = joinPath;
        this.alias = alias;
        this.type = type;
    }

    public static QueryDslFetchJoin innerJoin(EntityPath path) {
        return new QueryDslFetchJoin(path, Join.INNER);
    }

    public static QueryDslFetchJoin join(EntityPath path) {
        return new QueryDslFetchJoin(path, Join.JOIN);
    }

    public static QueryDslFetchJoin leftJoin(EntityPath path) {
        return new QueryDslFetchJoin(path, Join.LEFT);
    }

    public static QueryDslFetchJoin rightJoin(EntityPath path) {
        return new QueryDslFetchJoin(path, Join.RIGHT);
    }

    public static QueryDslFetchJoin innerJoin(EntityPath path, EntityPath alias) {
        return new QueryDslFetchJoin(path, alias, Join.INNER_ALIAS);
    }

    public static QueryDslFetchJoin join(EntityPath path, EntityPath alias) {
        return new QueryDslFetchJoin(path, alias, Join.JOIN_ALIAS);
    }

    public static QueryDslFetchJoin leftJoin(EntityPath path, EntityPath alias) {
        return new QueryDslFetchJoin(path, alias, Join.LEFT_ALIAS);
    }

    public static QueryDslFetchJoin rightJoin(EntityPath path, EntityPath alias) {
        return new QueryDslFetchJoin(path, alias, Join.RIGHT_ALIAS);
    }

    public static enum Join {
        INNER, LEFT, RIGHT, JOIN, INNER_ALIAS, LEFT_ALIAS, RIGHT_ALIAS, JOIN_ALIAS
    }


}