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 org.apache.juneau.*;
016import org.apache.juneau.json.*;
017import org.apache.juneau.rest.*;
018import org.apache.juneau.rest.exception.*;
019import org.apache.juneau.transform.*;
020import org.apache.juneau.utils.*;
021
022/**
023 * Converter for enablement of {@link PojoIntrospector} support on response objects returned by a
024 * <code>@RestMethod</code> method.
025 *
026 * <p>
027 * When enabled, public methods can be called on objects returned through the {@link RestResponse#setOutput(Object)}
028 * method.
029 *
030 * <p>
031 * Note that opening up public methods for calling through a REST interface can be dangerous, and should be done with
032 * caution.
033 *
034 * <p>
035 * Java methods are invoked by passing in the following URL parameters:
036 * <ul class='spaced-list'>
037 *    <li>
038 *       <code>&amp;invokeMethod</code> - The Java method name, optionally with arguments if necessary to
039 *       differentiate between methods.
040 *    <li>
041 *       <code>&amp;invokeArgs</code> - The arguments as an array.
042 * </ul>
043 *
044 * <h5 class='section'>See Also:</h5>
045 * <ul>
046 *    <li class='jc'>{@link PojoIntrospector} - Additional information on introspection of POJO methods.
047 *    <li class='jf'>{@link RestContext#REST_converters} - Registering converters with REST resources.
048 *    <li class='link'>{@doc juneau-rest-server.Converters}
049 * </ul>
050 */
051public final class Introspectable implements RestConverter {
052
053   /**
054    * Swagger parameters for this converter.
055    */
056   public static final String SWAGGER_PARAMS= ""
057      + "{in:'query',name:'invokeMethod',description:' The Java method name, optionally with arguments if necessary to differentiate between methods.',x-examples:{example:'toString'}},"
058      + "{in:'query',name:'invokeArgs',description:'The arguments as an array.',x-examples:{example:'foo,bar'}}"
059   ;
060
061   @Override /* RestConverter */
062   @SuppressWarnings({"unchecked", "rawtypes"})
063   public Object convert(RestRequest req, Object o) throws InternalServerError {
064      String method = req.getQuery().getString("invokeMethod");
065      String args = req.getQuery().getString("invokeArgs");
066      if (method == null)
067         return o;
068      try {
069         BeanSession bs = req.getBeanSession();
070         PojoSwap swap = bs.getClassMetaForObject(o).getPojoSwap(bs);
071         if (swap != null)
072            o = swap.swap(bs, o);
073         return new PojoIntrospector(o, JsonParser.DEFAULT).invokeMethod(method, args);
074      } catch (Exception e) {
075         return new InternalServerError(
076            "Error occurred trying to invoke method: {0}",
077            e.getLocalizedMessage()
078         ).initCause(e);
079      }
080   }
081}