com.intelligentsia.dowsers.entity.store.memory.InMemoryEntityStore.java Source code

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Here is the source code for com.intelligentsia.dowsers.entity.store.memory.InMemoryEntityStore.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.
 *
 */
package com.intelligentsia.dowsers.entity.store.memory;

import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.Map;
import java.util.Set;

import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.Collections2;
import com.google.common.collect.Maps;
import com.google.common.io.Closeables;
import com.intelligentsia.dowsers.entity.reference.Reference;
import com.intelligentsia.dowsers.entity.reference.References;
import com.intelligentsia.dowsers.entity.serializer.EntityMapper;
import com.intelligentsia.dowsers.entity.store.AbstractEntityStore;
import com.intelligentsia.dowsers.entity.store.ConcurrencyException;
import com.intelligentsia.dowsers.entity.store.EntityNotFoundException;
import com.intelligentsia.dowsers.entity.store.EntityStore;

/**
 * InMemoryEntityStore implements a {@link EntityStore} in memory (only for
 * testing purpose no ?).
 * 
 * @author <a href="mailto:jguibert@intelligents-ia.com" >Jerome Guibert</a>
 */
public class InMemoryEntityStore extends AbstractEntityStore implements EntityStore {

    private final Map<Reference, String> entities = Maps.newHashMap();
    /**
     * {@link EntityMapper} instance.
     */
    private final EntityMapper entityMapper;

    /**
     * Build a new instance of InMemoryEntityStore.java.
     */
    public InMemoryEntityStore(final EntityMapper entityMapper) throws NullPointerException {
        super();
        this.entityMapper = Preconditions.checkNotNull(entityMapper);
    }

    @Override
    public Iterable<Reference> find(final Class<?> expectedType) throws NullPointerException {
        final Reference reference = Reference.newReferenceOnEntityClass(expectedType);
        final Set<Reference> references = entities.keySet();

        Collections2.filter(references, new Predicate<Reference>() {

            @Override
            public boolean apply(final Reference input) {
                if (input != null) {
                    return reference.equals(input.getEntityClassReference());
                }
                return false;
            }

        });
        return references;
    }

    @Override
    public <T> T find(final Class<T> expectedType, final Reference reference)
            throws EntityNotFoundException, NullPointerException, IllegalArgumentException {
        final String data = entities.get(reference);
        if (data == null) {
            throw new EntityNotFoundException();
        }
        Reader reader = null;
        try {
            reader = new StringReader(data);
            return entityMapper.readValue(reader, expectedType);
        } finally {
            if (reader != null) {
                Closeables.closeQuietly(reader);
            }
        }
    }

    @Override
    public <T> void store(final T entity)
            throws NullPointerException, ConcurrencyException, IllegalArgumentException {
        Writer writer = null;
        try {
            writer = new StringWriter();
            entityMapper.writeValue(writer, entity);
            entities.put(References.identify(entity), writer.toString());
        } finally {
            if (writer != null) {
                Closeables.closeQuietly(writer);
            }
        }
    }

    @Override
    public <T> void remove(final T entity) throws NullPointerException, IllegalArgumentException {
        entities.remove(References.identify(entity));
    }

    @Override
    public void remove(final Reference reference) throws NullPointerException, IllegalArgumentException {
        entities.remove(reference);
    }

}