com.frank.search.solr.core.query.ExistsFunction.java Source code

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Here is the source code for com.frank.search.solr.core.query.ExistsFunction.java

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/*
 * Copyright 2012 - 2013 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 com.frank.search.solr.core.query;

import org.springframework.util.Assert;

import java.util.Arrays;

/**
 * Implementation of {@code exists(field|function)}
 * 
 * @author Christoph Strobl
 * @since 1.1
 */
public class ExistsFunction extends AbstractFunction {

    private static final String OPERATION = "exists";

    private ExistsFunction(Object candidate) {
        super(Arrays.asList(candidate));
    }

    /**
     * Creates new {@link ExistsFunction} representing {@code exists(field)}
     *
     * @param field
     * @return
     */
    public static ExistsFunction exists(Field field) {
        Assert.notNull(field, "Field cannot be 'null' for exists operation.");

        return exists(field.getName());
    }

    /**
     * Creates new {@link ExistsFunction} representing {@code exists(fieldname)}
     *
     * @param fieldname
     * @return
     */
    public static ExistsFunction exists(String fieldname) {
        Assert.hasText(fieldname, "Fieldname cannot be 'empty' for exists operation.");

        return new ExistsFunction(fieldname);
    }

    /**
     * Creates new {@link ExistsFunction} representing {@code exists(function())}
     * 
     * @param function
     * @return
     */
    public static ExistsFunction exists(Function function) {
        Assert.notNull(function, "Function cannot be 'null' for exists operation.");

        return new ExistsFunction(function);
    }

    @Override
    public String getOperation() {
        return OPERATION;
    }

}