cosmos.sql.call.impl.Projection.java Source code

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Here is the source code for cosmos.sql.call.impl.Projection.java

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/**
 * 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.
 *
 *  Copyright 2013 
 *
 */
package cosmos.sql.call.impl;

import java.util.List;

import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;

import cosmos.sql.call.BaseVisitor;
import cosmos.sql.call.CallIfc;
import cosmos.sql.call.Field;

public class Projection extends BaseVisitor<CallIfc<?>> {

    public Projection() {

    }

    @Override
    public CallIfc<?> addChild(String id, CallIfc<?> child) {
        Preconditions.checkArgument(child instanceof Field);
        return super.addChild(id, child);
    }

    public List<Field> getProjections() {
        return Lists.newArrayList(Iterables.transform(children.values(), new Function<CallIfc<?>, Field>() {

            @Override
            public Field apply(CallIfc<?> child) {
                return (Field) child;
            }

        }));
    }
}