com.joyveb.dbpimpl.cass.prepare.mapping.BasicCassandraPersistentEntity.java Source code

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Here is the source code for com.joyveb.dbpimpl.cass.prepare.mapping.BasicCassandraPersistentEntity.java

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/*
 * Copyright 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.joyveb.dbpimpl.cass.prepare.mapping;

import java.util.Comparator;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.expression.BeanFactoryAccessor;
import org.springframework.context.expression.BeanFactoryResolver;
import org.springframework.data.mapping.model.BasicPersistentEntity;
import org.springframework.data.util.TypeInformation;
import org.springframework.expression.Expression;
import org.springframework.expression.ParserContext;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.util.StringUtils;

/**
 * Cassandra specific {@link BasicPersistentEntity} implementation that adds Cassandra specific meta-data such as the
 * table name.
 * 
 * @author Alex Shvid
 */
public class BasicCassandraPersistentEntity<T> extends BasicPersistentEntity<T, CassandraPersistentProperty>
        implements CassandraPersistentEntity<T>, ApplicationContextAware {

    private final String table;
    private final SpelExpressionParser parser;
    private final StandardEvaluationContext context;

    /**
     * Creates a new {@link BasicCassandraPersistentEntity} with the given {@link TypeInformation}. Will default the table
     * name to the entities simple type name.
     * 
     * @param typeInformation
     */
    public BasicCassandraPersistentEntity(TypeInformation<T> typeInformation) {

        super(typeInformation, CassandraPersistentPropertyComparator.INSTANCE);

        this.parser = new SpelExpressionParser();
        this.context = new StandardEvaluationContext();

        Class<?> rawType = typeInformation.getType();
        String fallback = rawType.getSimpleName().toLowerCase();

        if (rawType.isAnnotationPresent(Table.class)) {
            Table d = rawType.getAnnotation(Table.class);
            this.table = StringUtils.hasText(d.name()) ? d.name() : fallback;
        } else {
            this.table = fallback;
        }
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.context.ApplicationContextAware#setApplicationContext(org.springframework.context.ApplicationContext)
     */
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

        context.addPropertyAccessor(new BeanFactoryAccessor());
        context.setBeanResolver(new BeanFactoryResolver(applicationContext));
        context.setRootObject(applicationContext);
    }

    /**
     * Returns the table the entity shall be persisted to.
     * 
     * @return
     */
    public String getTableName() {
        Expression expression = parser.parseExpression(table, ParserContext.TEMPLATE_EXPRESSION);
        return expression.getValue(context, String.class);
    }

    /**
     * {@link Comparator} implementation inspecting the {@link CassandraPersistentProperty}'s order.
     * 
     * @author Alex Shvid
     */
    static enum CassandraPersistentPropertyComparator implements Comparator<CassandraPersistentProperty> {

        INSTANCE;

        /*
         * (non-Javadoc)
         * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
         */
        public int compare(CassandraPersistentProperty o1, CassandraPersistentProperty o2) {

            return o1.getColumnName().compareTo(o2.getColumnName());

        }
    }

}