001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
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006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
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012// ***************************************************************************************************************************
013package org.apache.juneau.rest.converters;
014
015import static javax.servlet.http.HttpServletResponse.*;
016
017import org.apache.juneau.*;
018import org.apache.juneau.json.*;
019import org.apache.juneau.rest.*;
020import org.apache.juneau.transform.*;
021import org.apache.juneau.utils.*;
022
023/**
024 * Converter for enablement of {@link PojoIntrospector} support on response objects returned by a
025 * <code>@RestMethod</code> method.
026 * 
027 * <p>
028 * When enabled, public methods can be called on objects returned through the {@link RestResponse#setOutput(Object)}
029 * method.
030 * 
031 * <p>
032 * Note that opening up public methods for calling through a REST interface can be dangerous, and should be done with
033 * caution.
034 * 
035 * <p>
036 * Java methods are invoked by passing in the following URL parameters:
037 * <ul class='spaced-list'>
038 *    <li>
039 *       <code>&amp;invokeMethod</code> - The Java method name, optionally with arguments if necessary to
040 *       differentiate between methods.
041 *    <li>
042 *       <code>&amp;invokeArgs</code> - The arguments as a JSON array.
043 * </ul>
044 * 
045 * <h5 class='section'>See Also:</h5>
046 * <ul>
047 *    <li class='jc'>{@link PojoIntrospector} - Additional information on introspection of POJO methods.
048 *    <li class='jf'>{@link RestContext#REST_converters} - Registering converters with REST resources.
049 *    <li class='link'><a class="doclink" href="../../../../../overview-summary.html#juneau-rest-server.Converters">Overview &gt; juneau-rest-server &gt; Converters</a>
050 * </ul>
051 */
052public final class Introspectable implements RestConverter {
053
054   @Override /* RestConverter */
055   @SuppressWarnings({"unchecked", "rawtypes"})
056   public Object convert(RestRequest req, Object o) throws RestException {
057      String method = req.getQuery().getString("invokeMethod");
058      String args = req.getQuery().getString("invokeArgs");
059      if (method == null)
060         return o;
061      try {
062         BeanSession bs = req.getBeanSession();
063         PojoSwap swap = bs.getClassMetaForObject(o).getPojoSwap(bs);
064         if (swap != null)
065            o = swap.swap(bs, o);
066         return new PojoIntrospector(o, JsonParser.DEFAULT).invokeMethod(method, args);
067      } catch (Exception e) {
068         e.printStackTrace();
069         return new RestException(SC_INTERNAL_SERVER_ERROR,
070            "Error occurred trying to invoke method: {0}",
071            e.getLocalizedMessage()
072         ).initCause(e);
073      }
074   }
075}