com.fluidops.iwb.api.valueresolver.ValueResolverUtil.java Source code

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Here is the source code for com.fluidops.iwb.api.valueresolver.ValueResolverUtil.java

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/*
 * Copyright (C) 2008-2013, fluid Operations AG
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
    
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
    
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

package com.fluidops.iwb.api.valueresolver;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.ServiceLoader;

import org.apache.commons.lang.StringEscapeUtils;
import org.apache.log4j.Logger;
import org.openrdf.model.Literal;
import org.openrdf.model.Value;

import com.fluidops.iwb.api.EndpointImpl;
import com.fluidops.iwb.api.ReadDataManagerImpl;
import com.fluidops.iwb.widget.config.ValueResolverConfig;
import com.fluidops.util.StringUtil;

/**
 * Convenience functions for value resolvers.
 * 
 * @author as
 *
 */
public class ValueResolverUtil {

    private static Logger logger = Logger.getLogger(ValueResolverUtil.class);

    /**
     * This method initializes custom {@link ValueResolver} extensions
     * using the Java {@link ServiceLoader} mechanism. It is invoked
     * on startup of the application, and looks up all registered
     * {@link ValueResolverFactory} in META-INF. See {@link ValueResolver}
     * for details.
     */
    public static void initializeValueResolverExtensions() {

        logger.info("Initializing value resolver extensions");

        ServiceLoader<ValueResolverFactory> serviceLoader = ServiceLoader.load(ValueResolverFactory.class);
        Iterator<ValueResolverFactory> iter = serviceLoader.iterator();
        while (iter.hasNext()) {
            ValueResolverFactory vrf = iter.next();
            ValueResolver valueResolver = vrf.create();
            logger.debug("Registered custom value resolver: " + valueResolver.name());
            ValueResolverRegistry.getInstance().register(valueResolver);
        }
    }

    /**
     * Default handling for URIs and Literals as of
     * {@link #resolveDefault(Value, String)} using
     * {@link ValueResolver#UNDEFINED} if the value
     * is not defined.
     * 
     * @param value
     * @return
     */
    public static String resolveDefault(Value value) {
        return resolveDefault(value, ValueResolver.UNDEFINED);
    }

    /**
     * Default handling for URIs and Literals.
     * 
     * @param value
     *            The value itself (URI/Literal)
     * @param def
     *            The default text in case the value cannot be resolved
     * @return Returns a String (= Literal) or a link (= URI)
     */
    public static String resolveDefault(Value value, String def) {
        if (value == null || value.stringValue().isEmpty())
            return def; // default value

        if (value instanceof Literal)
            return StringEscapeUtils.escapeHtml(value.stringValue());
        else
            return EndpointImpl.api().getRequestMapper().getAHrefFromValue(value);
    }

    /**
      * Converts a system date like '2011-03-31T19:54:33' to user-readable date.
      * If the input is not a valid system date, the value is returned as is.
      * 
      * @param sysdate
      * @return
      */
    @SuppressWarnings("deprecation")
    public static String resolveSystemDate(String sysdate) {

        Date d = ReadDataManagerImpl.ISOliteralToDate(sysdate);
        if (d == null)
            return StringEscapeUtils.escapeHtml(sysdate);

        DateFormat df = null;
        if (d.getHours() == 0 && d.getMinutes() == 0 && d.getSeconds() == 0)
            df = new SimpleDateFormat("MMMMM dd, yyyy");
        else
            df = new SimpleDateFormat("MMMMM dd, yyyy, HH:mm:ss");
        return df.format(d);

    }

    /**
     * Return the value resolvers as defined by the user input.
     * The string valueResolver is a legacy parameter, but still supported.
     * The variable resolver will be preferably taken from the valueConfiguration.
     * @param valueResolver
     * @param valueConfiguration
     * @return
     */
    public static Map<String, String> getValueResolvers(String valueResolver,
            List<? extends ValueResolverConfig> valueConfiguration) {

        Map<String, String> varResolvers = new HashMap<String, String>();

        if (StringUtil.isNotNullNorEmpty(valueResolver) && !hasValueResolvers(valueConfiguration)) {
            String[] s = valueResolver.split(",");
            for (int i = 0; i < s.length; i++) {
                String[] s2 = s[i].split("=");
                if (s2.length == 2)
                    varResolvers.put(s2[0], s2[1]);
                else
                    throw new IllegalArgumentException(
                            "ValueResolver parameter specified incorrectly, comma separated mappings are expected.");
            }
        }

        if (valueConfiguration != null) {
            for (ValueResolverConfig vrc : valueConfiguration) {
                if (StringUtil.isNotNullNorEmpty(vrc.getVariableName()) && vrc.getValueResolver() != null)
                    varResolvers.put(vrc.getVariableName(), vrc.getValueResolver().toString());
            }
        }
        return varResolvers;
    }

    /**
     * check if value resolvers are defined in valueConfiguration
     * @param valueConfiguration
     * @return
     */
    public static boolean hasValueResolvers(List<? extends ValueResolverConfig> valueConfiguration) {
        if (valueConfiguration != null)
            for (ValueResolverConfig vrc : valueConfiguration) {
                if (vrc.getValueResolver() != null)
                    return true;
            }
        return false;
    }
}