BundleStrings.java

/**
 * Licensed to the Austrian Association for Software Tool Integration (AASTI)
 * under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership. The AASTI 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 org.openengsb.core.api.l10n;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.text.MessageFormat;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Properties;

import org.apache.commons.lang.LocaleUtils;
import org.osgi.framework.Bundle;
import org.osgi.framework.Constants;

/**
 * Localization helper to lookup string resources from the bundle's localization entries.
 */
@SuppressWarnings("serial")
public class BundleStrings implements StringLocalizer {

    private HashMap<String, Properties> entries;

    public BundleStrings() {
    }

    public BundleStrings(Bundle bundle) {
        setBundle(bundle);
    }

    @Override
    public LocalizableString getString(final String key, final String... parameters) {
        return new LocalizableString() {
            @Override
            public String getString(Locale locale) {
                return BundleStrings.this.getString(key, locale, parameters);
            }

            @Override
            public String getKey() {
                return key;
            }
        };
    }

    @Override
    public String getString(String key, Locale locale, String... parameters) {
        @SuppressWarnings("unchecked")
        List<Locale> locales = LocaleUtils.localeLookupList(locale, new Locale(""));
        for (Locale l : locales) {
            Properties p = entries.get(buildEntryFilename(l));
            if (p == null) {
                continue;
            }
            if (p.containsKey(key)) {
                String property = p.getProperty(key);
                String format = MessageFormat.format(property, (Object[]) parameters);
                return format;
            }
        }
        return null;
    }

    private String buildEntryFilename(Locale locale) {
        String name = "";
        if (!locale.getLanguage().isEmpty()) {
            name += '_' + locale.getLanguage();
            if (!locale.getCountry().isEmpty()) {
                name += '_' + locale.getCountry();
                if (!locale.getVariant().isEmpty()) {
                    name += '_' + locale.getVariant();
                }
            }
        }
        return name;
    }

    public void setBundle(Bundle bundle) {
        String path = (String) bundle.getHeaders().get(Constants.BUNDLE_LOCALIZATION);
        if (path == null) {
            path = Constants.BUNDLE_LOCALIZATION_DEFAULT_BASENAME;
        }
        path = path.trim();
        int idx = path.lastIndexOf('/');
        if (idx == -1) {
            buildEntriesMap(bundle, "/", path);
        } else if (idx == 0) {
            buildEntriesMap(bundle, "/", path.substring(1));
        } else {
            buildEntriesMap(bundle, path.substring(0, idx), path.substring(idx + 1));
        }
    }

    private void buildEntriesMap(Bundle bundle, String directory, String basename) {
        @SuppressWarnings("unchecked")
        Enumeration<URL> resources = bundle.findEntries(directory, basename + "*.properties", false);
        entries = new HashMap<String, Properties>();
        while (resources != null && resources.hasMoreElements()) {
            URL url = resources.nextElement();
            String name = new File(url.toString()).getName().substring(basename.length());
            name = name.substring(0, name.length() - ".properties".length());
            Properties p = loadProperties(url);
            if (p != null) {
                entries.put(name, p);
            }
        }
    }

    private Properties loadProperties(URL url) {
        InputStream in = null;
        try {
            in = url.openStream();
            Properties p = new Properties();
            p.load(in);
            return p;
        } catch (IOException e) {
            return null;
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    // nop
                }
            }
        }
    }
}