org.ldaptive.io.JsonReader.java Source code

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Here is the source code for org.ldaptive.io.JsonReader.java

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/* See LICENSE for licensing and NOTICE for copyright. */
package org.ldaptive.io;

import java.io.IOException;
import java.io.Reader;
import java.lang.reflect.Type;
import java.util.Map;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import org.ldaptive.LdapAttribute;
import org.ldaptive.LdapEntry;
import org.ldaptive.SearchResult;
import org.ldaptive.SortBehavior;

/**
 * Reads JSON from a {@link Reader} and returns a {@link SearchResult}.
 *
 * @author  Middleware Services
 */
public class JsonReader implements SearchResultReader {

    /** Reader to read from. */
    private final Reader jsonReader;

    /** To convert JSON to a search result. */
    private final Gson gson;

    /**
     * Creates a new json reader.
     *
     * @param  reader  to read JSON from
     */
    public JsonReader(final Reader reader) {
        this(reader, SortBehavior.getDefaultSortBehavior());
    }

    /**
     * Creates a new json reader.
     *
     * @param  reader  to read JSON from
     * @param  sb  sort behavior of the search result
     */
    public JsonReader(final Reader reader, final SortBehavior sb) {
        jsonReader = reader;
        if (sb == null) {
            throw new IllegalArgumentException("Sort behavior cannot be null");
        }
        final GsonBuilder builder = new GsonBuilder();
        builder.registerTypeAdapter(SearchResult.class, new SearchResultDeserializer(sb));
        gson = builder.disableHtmlEscaping().create();
    }

    /**
     * Reads JSON data from the reader and returns a search result.
     *
     * @return  search result derived from the JSON
     *
     * @throws  IOException  if an error occurs using the reader
     */
    @Override
    public SearchResult read() throws IOException {
        try {
            return gson.fromJson(jsonReader, SearchResult.class);
        } catch (JsonParseException e) {
            throw new IOException(e);
        }
    }

    /**
     * Deserializes a {@link SearchResult} by iterating over the json elements.
     */
    private static class SearchResultDeserializer implements JsonDeserializer<SearchResult> {

        /** Sort behavior. */
        private final SortBehavior sortBehavior;

        /**
         * Creates a new search result deserializer.
         *
         * @param  sb  sort behavior of the search result
         */
        SearchResultDeserializer(final SortBehavior sb) {
            sortBehavior = sb;
        }

        @Override
        public SearchResult deserialize(final JsonElement json, final Type type,
                final JsonDeserializationContext context) throws JsonParseException {
            final SearchResult result = new SearchResult(sortBehavior);
            final JsonArray jsonResult = json.getAsJsonArray();
            for (JsonElement jsonEntry : jsonResult) {
                final LdapEntry entry = new LdapEntry(sortBehavior);
                for (Map.Entry<String, JsonElement> jsonAttr : jsonEntry.getAsJsonObject().entrySet()) {
                    if ("dn".equals(jsonAttr.getKey())) {
                        entry.setDn(jsonAttr.getValue().getAsString());
                    } else {
                        final LdapAttribute attr = new LdapAttribute(sortBehavior);
                        attr.setName(jsonAttr.getKey());
                        jsonAttr.getValue().getAsJsonArray().forEach(i -> attr.addStringValue(i.getAsString()));
                        entry.addAttribute(attr);
                    }
                }
                result.addEntry(entry);
            }
            return result;
        }
    }
}