org.cloudifysource.cosmo.kvstore.KVStore.java Source code

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Here is the source code for org.cloudifysource.cosmo.kvstore.KVStore.java

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/*******************************************************************************
 * Copyright (c) 2011 GigaSpaces Technologies Ltd. All rights reserved
 *
 * 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 org.cloudifysource.cosmo.kvstore;

import java.net.URI;
import java.util.Map;

import javax.ws.rs.core.EntityTag;

import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
import com.google.common.collect.Maps;

public class KVStore implements KVReader, KVWriter {

    final Map<URI, EntityTagState<String>> store = Maps.newLinkedHashMap();

    @Override
    public Optional<EntityTagState<String>> getState(URI key) {
        synchronized (store) {

            EntityTagState<String> value = store.get(key);
            return Optional.fromNullable(value);
        }
    }

    @Override
    public Optional<EntityTag> getEntityTag(URI key) {
        EntityTag etag = null;
        final EntityTagState<String> value = store.get(key);
        if (value != null) {
            etag = value.getEntityTag();
        }
        return Optional.fromNullable(etag);
    }

    @Override
    public EntityTag put(URI key, String state) {
        Preconditions.checkNotNull(key);
        Preconditions.checkNotNull(state);

        final EntityTag etag = KVEntityTag.create(state);
        final EntityTagState<String> value = new EntityTagState<String>(etag, state);
        store.put(key, value);
        return etag;

    }

    @Override
    public Iterable<URI> listKeysStartsWith(final URI keyPrefix) {
        return Iterables.filter(store.keySet(), new Predicate<URI>() {

            @Override
            public boolean apply(URI key) {
                return key.toString().startsWith(keyPrefix.toString());
            }
        });
    }

    public void clear() {
        synchronized (store) {
            store.clear();
        }
    }

    static class EntityTagState<T> {

        private final EntityTag etag;

        private final T state;

        public EntityTagState(EntityTag etag, T state) {
            Preconditions.checkNotNull(state);
            Preconditions.checkNotNull(etag);
            this.etag = etag;
            this.state = state;
        }

        public EntityTag getEntityTag() {
            return etag;
        }

        public T getState() {
            return state;
        }
    }
}