/*******************************************************************************
* Copyright 2012 André Rouél
*
* 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 net.sf.uadetector.datastore;
import java.net.URL;
import java.nio.charset.Charset;
import javax.annotation.Nonnull;
import net.sf.qualitycheck.Check;
import net.sf.uadetector.datareader.DataReader;
import net.sf.uadetector.internal.data.Data;
import net.sf.uadetector.internal.util.UrlUtil;
/**
* The abstract implementation to store <em>UAS data</em> only in the heap space.<br>
* <br>
* A store must always have an usable instance of {@link Data}. It is recommended to initialize it with the supplied UAS
* file in the <em>uadetector-resources</em> module.
*
* @author André Rouél
*/
public abstract class AbstractDataStore implements DataStore {
/**
* Runtime check that the passed instance of {@link Data} is not empty (respectively {@link Data#EMPTY}).
*
* @param data
* instance of {@code Data}
* @throws IllegalStateException
* if the passed instance is empty
*/
private static Data checkData(final Data data) {
if (Data.EMPTY.equals(data)) {
throw new IllegalStateException("Argument 'data' must not be empty.");
}
return data;
}
/**
* This method reads the given {@link URL} by using an {@link DataReader}. The new created instance of {@link Data}
* will be returned.
*
* @param reader
* data reader to read the given {@code dataUrl}
* @param url
* URL to <em>UAS data</em>
* @param charset
* the character set in which the data should be read
* @return an instance of {@code Data} or {@link Data#EMPTY} if an error occurred, but never {@code null}
* @throws net.sf.qualitycheck.exception.IllegalNullArgumentException
* if the given argument is {@code null}
*/
protected static final Data readData(@Nonnull final DataReader reader, @Nonnull final URL url, @Nonnull final Charset charset) {
Check.notNull(reader, "reader");
Check.notNull(url, "url");
Check.notNull(charset, "charset");
return reader.read(url, charset);
}
/**
* Current the character set in which the <em>UAS data</em> will be read
*/
private final Charset charset;
/**
* Current <em>UAS data</em>
*/
private final Data data;
/**
* The {@code URL} to get <em>UAS data</em>
*/
private final URL dataUrl;
/**
* The data reader to read in <em>UAS data</em>
*/
private final DataReader reader;
/**
* The {@code URL} to get the latest version information of <em>UAS data</em>
*/
private final URL versionUrl;
/**
* Constructs an new instance of {@link AbstractDataStore}.
*
* @param data
* first <em>UAS data</em> which will be available in the store
* @param reader
* data reader to read the given {@code dataUrl}
* @param dataUrl
* URL to <em>UAS data</em>
* @param versionUrl
* URL to version information about the given <em>UAS data</em>
* @param charset
* the character set in which the data should be read
* @throws net.sf.qualitycheck.exception.IllegalNullArgumentException
* if one of the given arguments is {@code null}
*/
protected AbstractDataStore(@Nonnull final Data data, @Nonnull final DataReader reader, @Nonnull final URL dataUrl,
@Nonnull final URL versionUrl, @Nonnull final Charset charset) {
Check.notNull(data, "data");
Check.notNull(reader, "reader");
Check.notNull(charset, "charset");
Check.notNull(dataUrl, "dataUrl");
Check.notNull(versionUrl, "versionUrl");
this.data = checkData(data);
this.reader = reader;
this.dataUrl = dataUrl;
this.versionUrl = versionUrl;
this.charset = charset;
}
/**
* Constructs an {@code AbstractDataStore} by reading the given {@code dataUrl} as <em>UAS data</em>.
*
* @param reader
* data reader to read the given {@code dataUrl}
* @param dataUrl
* URL to <em>UAS data</em>
* @param versionUrl
* URL to version information about the given <em>UAS data</em>
* @param charset
* the character set in which the data should be read
* @throws net.sf.qualitycheck.exception.IllegalNullArgumentException
* if one of the given arguments is {@code null}
* @throws net.sf.qualitycheck.exception.IllegalNullArgumentException
* if the given strings are not valid URLs
*/
protected AbstractDataStore(final DataReader reader, final String dataUrl, final String versionUrl, final Charset charset) {
this(reader, UrlUtil.build(dataUrl), UrlUtil.build(versionUrl), charset);
}
/**
* Constructs an {@code AbstractDataStore} by reading the given {@code dataUrl} as <em>UAS data</em>.
*
* @param reader
* data reader to read the given {@code dataUrl}
* @param dataUrl
* URL to <em>UAS data</em>
* @param versionUrl
* URL to version information about the given <em>UAS data</em>
* @param charset
* the character set in which the data should be read
* @throws net.sf.qualitycheck.exception.IllegalNullArgumentException
* if the given argument is {@code null}
* @throws net.sf.qualitycheck.exception.IllegalStateOfArgumentException
* if the created instance of {@link Data} is empty
*/
protected AbstractDataStore(final DataReader reader, final URL dataUrl, final URL versionUrl, final Charset charset) {
this(checkData(readData(reader, dataUrl, charset)), reader, dataUrl, versionUrl, charset);
}
@Override
public Charset getCharset() {
return charset;
}
@Override
public Data getData() {
return data;
}
@Override
public DataReader getDataReader() {
return reader;
}
@Override
public URL getDataUrl() {
return dataUrl;
}
@Override
public URL getVersionUrl() {
return versionUrl;
}
}