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

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Here is the source code for com.frank.search.solr.core.query.ParameterHolder.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.*;

/**
 * Generic holder of additional parameters that can be added to a query. eg. per field overrides. <br />
 * The order in which elements are added will be preserved.
 * 
 * @author Christoph Strobl
 */
class ParameterHolder<T extends QueryParameter> implements Iterable<T> {

    private final Map<String, T> parameters = new LinkedHashMap<String, T>(1);

    @SuppressWarnings("unchecked")
    public <S> S getParameterValue(String parameterName) {
        T parameter = this.parameters.get(parameterName);
        if (parameter == null) {
            return null;
        }
        return (S) parameter.getValue();
    }

    /**
     * add a query parameter
     * 
     * @param queryParameter must not be null
     */
    public void add(T queryParameter) {
        Assert.notNull(queryParameter);
        this.parameters.put(queryParameter.getName(), queryParameter);
    }

    /**
     * @param parameterName
     * @return null if not found
     */
    public T get(String parameterName) {
        return this.parameters.get(parameterName);
    }

    /**
     * remove parameter with given name
     * 
     * @param parameterName
     */
    public T remove(String parameterName) {
        return this.parameters.remove(parameterName);
    }

    /**
     * @return unmodifiable collection of all parameters present
     */
    public Collection<T> getParameters() {
        return Collections.unmodifiableCollection(this.parameters.values());
    }

    @Override
    public Iterator<T> iterator() {
        return this.parameters.values().iterator();
    }

    /**
     * @return true if holder does not contain any values
     */
    public boolean isEmpty() {
        return this.parameters.isEmpty();
    }

}