// ***************************************************************************************************************************
// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
// * distributed with this work for additional information regarding copyright ownership.  The ASF 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.apache.juneau;

import static org.apache.juneau.internal.ClassUtils.*;
import static org.apache.juneau.internal.CollectionUtils.*;
import static org.apache.juneau.internal.ConsumerUtils.*;
import static org.apache.juneau.collections.JsonMap.*;
import static org.apache.juneau.common.internal.ThrowableUtils.*;

import java.lang.annotation.Annotation;
import java.lang.reflect.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;

import org.apache.juneau.annotation.*;
import org.apache.juneau.collections.*;
import org.apache.juneau.csv.annotation.*;
import org.apache.juneau.html.annotation.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.json.annotation.*;
import org.apache.juneau.jsonschema.annotation.*;
import org.apache.juneau.msgpack.annotation.*;
import org.apache.juneau.oapi.annotation.*;
import org.apache.juneau.parser.annotation.*;
import org.apache.juneau.plaintext.annotation.*;
import org.apache.juneau.reflect.*;
import org.apache.juneau.serializer.annotation.*;
import org.apache.juneau.soap.annotation.*;
import org.apache.juneau.svl.*;
import org.apache.juneau.uon.annotation.*;
import org.apache.juneau.urlencoding.annotation.*;
import org.apache.juneau.utils.*;
import org.apache.juneau.xml.annotation.*;

/**
 * Base class for all Context beans.
 *
 * <p>
 * Context beans follow the convention of havinTg the following parts:
 * <ul>
 *    <li>A {@link Builder} class for configuring the context bean.
 *    <ul>
 *       <li>This bean is non-thread-safe and meant for one-time use.
 *    </ul>
 *    <li>A {@link Context#Context(Builder)} constructor that takes in a builder object.
 *    <ul>
 *       <li>This bean is thread-safe and cacheable/reusable.
 *    </ul>
 *    <li>A {@link ContextSession} class for doing work.
 *    <ul>
 *       <li>This bean is non-thread-safe and meant for one-time use.
 *    </ul>
 *
 * <h5 class='section'>Notes:</h5><ul>
 *    <li class='note'>This class is thread safe and reusable.
 * </ul>
 *
 * <h5 class='section'>See Also:</h5><ul>
 * </ul>
 */
public abstract class Context implements AnnotationProvider {

   //-----------------------------------------------------------------------------------------------------------------
   // Static
   //-----------------------------------------------------------------------------------------------------------------

   private static final Map<Class<?>,MethodInfo> BUILDER_CREATE_METHODS = new ConcurrentHashMap<>();

   /**
    * Predicate for annotations that themselves are annotated with {@link ContextApply}.
    */
   public static final Predicate<AnnotationInfo<?>> CONTEXT_APPLY_FILTER = x -> x.hasAnnotation(ContextApply.class);

   /**
    * Instantiates a builder of the specified context class.
    *
    * <p>
    * Looks for a public static method called <c>create</c> that returns an object that can be passed into a public
    * or protected constructor of the class.
    *
    * @param type The builder to create.
    * @return A new builder.
    */
   public static Builder createBuilder(Class<? extends Context> type) {
      try {
         MethodInfo mi = BUILDER_CREATE_METHODS.get(type);
         if (mi == null) {
            ClassInfo c = ClassInfo.of(type);
            for (ConstructorInfo ci : c.getPublicConstructors()) {
               if (ci.matches(x -> x.hasNumParams(1) && ! x.getParam(0).getParameterType().is(type))) {
                  mi = c.getPublicMethod(
                     x -> x.isStatic()
                     && x.isNotDeprecated()
                     && x.hasName("create")
                     && x.hasReturnType(ci.getParam(0).getParameterType())
                  );
                  if (mi != null)
                     break;
               }
            }
            if (mi == null)
               throw new BasicRuntimeException("Could not find builder create method on class {0}", type);
            BUILDER_CREATE_METHODS.put(type, mi);
         }
         Builder b = (Builder)mi.invoke(null);
         b.type(type);
         return b;
      } catch (ExecutableException e) {
         throw asRuntimeException(e);
      }
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Builder
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Builder class.
    */
   @FluentSetters
   public static abstract class Builder {

      private static final Map<Class<?>,ConstructorInfo> CONTEXT_CONSTRUCTORS = new ConcurrentHashMap<>();

      boolean debug;
      Class<? extends Context> type;
      Context impl;
      List<Annotation> annotations;
      Cache<HashKey,? extends Context> cache;

      private final List<Object> builders = list();
      private final AnnotationWorkList applied = AnnotationWorkList.create();

      /**
       * Constructor.
       * Default settings.
       */
      @SuppressWarnings("unchecked")
      protected Builder() {
         debug = env("Context.debug", false);
         annotations = null;
         registerBuilders(this);

         // By default, the type being created should be the class declaring the builder.
         Class<?> dc = getClass().getDeclaringClass();
         if (Context.class.isAssignableFrom(dc))
            type((Class<? extends Context>)dc);
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The bean to copy from.
       */
      protected Builder(Context copyFrom) {
         debug = copyFrom.debug;
         type = copyFrom.getClass();
         annotations = listFrom(copyFrom.annotations, true);
         registerBuilders(this);
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The builder to copy from.
       */
      protected Builder(Builder copyFrom) {
         debug = copyFrom.debug;
         type = copyFrom.type;
         annotations = listFrom(copyFrom.annotations, true);
         registerBuilders(this);
      }

      private Context innerBuild() {
         if (type == null)
            throw new BasicRuntimeException("Type not specified for context builder {0}", getClass().getName());
         if (impl != null && type.isInstance(impl))
            return type.cast(impl);
         if (cache != null)
            return cache.get(hashKey(), ()->getContextConstructor().invoke(this));
         return getContextConstructor().invoke(this);
      }

      private ConstructorInfo getContextConstructor() {
         ConstructorInfo cci = CONTEXT_CONSTRUCTORS.get(type);
         if (cci == null) {
            cci = ClassInfo.of(type).getPublicConstructor(
               x -> x.hasNumParams(1)
               && x.getParam(0).canAccept(this)
            );
            if (cci == null)
               throw new BasicRuntimeException("Public constructor not found: {0}({1})", className(type), className(this));
            CONTEXT_CONSTRUCTORS.put(type, cci);
         }
         return cci;
      }

      /**
       * Copy creator.
       *
       * @return A new mutable copy of this builder.
       */
      public abstract Builder copy();

      /**
       * Build the object.
       *
       * @return The built object.
       */
      public Context build() {
         return innerBuild();
      }

      /**
       * Returns the hashkey of this builder.
       *
       * <p>
       * Used to return previously instantiated context beans that have matching hashkeys.
       * The {@link HashKey} object is suitable for use as a hashmap key of a map of context beans.
       * A context bean is considered equivalent if the {@link HashKey#equals(Object)} method is the same.
       *
       * @return The hashkey of this builder.
       */
      public HashKey hashKey() {
         return HashKey.of(debug, type, annotations);
      }

      /**
       * Specifies a cache to use for hashkey-based caching.
       *
       * @param value The cache.
       * @return This object.
       */
      @FluentSetter
      public Builder cache(Cache<HashKey,? extends Context> value) {
         this.cache = value;
         return this;
      }

      /**
       * Convenience method for calling {@link #build()} while avoiding a cast.
       *
       * @param <T> The type to cast the built object to.
       * @param c The type to cast the built object to.
       * @return The built context bean.
       */
      @SuppressWarnings("unchecked")
      public final <T extends Context> T build(Class<T> c) {
         if (type == null || ! c.isAssignableFrom(type))
            type = c;
         return (T)innerBuild();
      }

      /**
       * Apply a consumer to this builder.
       *
       * @param <T> The builder subtype that this consumer can be applied to.
       * @param subtype The builder subtype that this consumer can be applied to.
       * @param consumer The consumer.
       * @return This object.
       */
      public <T extends Builder> Builder apply(Class<T> subtype, Consumer<T> consumer) {
         if (subtype.isInstance(this))
            consumer.accept(subtype.cast(this));
         return this;
      }

      /**
       * Associates a context class with this builder.
       *
       * <p>
       * This is the type of object that this builder creates when the {@link #build()} method is called.
       *
       * <p>
       * By default, it's the outer class of where the builder class is defined.
       *
       * @param value The context class that this builder should create.
       * @return This object.
       */
      @FluentSetter
      public Builder type(Class<? extends Context> value) {
         this.type = value;
         return this;
      }

      /**
       * Returns the context class that this builder should create.
       *
       * @return The context class if it was specified.
       */
      public Optional<Class<?>> getType() {
         return optional(type);
      }

      /**
       * Specifies a pre-instantiated bean for the {@link #build()} method to return.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      @FluentSetter
      public Builder impl(Context value) {
         impl = value;
         return this;
      }

      /**
       * Returns <jk>true</jk> if any of the annotations/appliers can be applied to this builder.
       *
       * @param work The work to check.
       * @return <jk>true</jk> if any of the annotations/appliers can be applied to this builder.
       */
      public boolean canApply(AnnotationWorkList work) {
         Flag f = Flag.create();
         work.forEach(x -> builders.forEach(b -> f.setIf(x.canApply(b))));
         return f.isSet();
      }

      /**
       * Applies a set of applied to this builder.
       *
       * <p>
       * An {@link AnnotationWork} consists of a single pair of {@link AnnotationInfo} that represents an annotation instance,
       * and {@link AnnotationApplier} which represents the code used to apply the values in that annotation to a specific builder.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// A class annotated with a config annotation.</jc>
       *    <ja>@BeanConfig</ja>(sortProperties=<js>"$S{sortProperties,false}"</js>)
       *    <jk>public class</jk> MyClass {...}
       *
       *    <jc>// Find all annotations that themselves are annotated with @ContextPropertiesApply.</jc>
       *    AnnotationList <jv>annotations</jv> = ClassInfo.<jsm>of</jsm>(MyClass.<jk>class</jk>).getAnnotationList(<jsf>CONTEXT_APPLY_FILTER</jsf>);
       *    VarResolverSession <jv>vrs</jv> = VarResolver.<jsf>DEFAULT</jsf>.createSession();
       *    AnnotationWorkList <jv>work</jv> = AnnotationWorkList.of(<jv>vrs</jv>, <jv>annotations</jv>);
       *
       *    <jc>// Apply any settings found on the annotations.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .apply(<jv>work</jv>)
       *       .build();
       * </p>
       *
       * @param work The list of annotations and appliers to apply to this builder.
       * @return This object.
       */
      @FluentSetter
      public Builder apply(AnnotationWorkList work) {
         applied.addAll(work);
         work.forEach(x -> builders.forEach(y -> x.apply(y)));
         return this;
      }

      /**
       * Returns all the annotations that have been applied to this builder.
       *
       * @return All the annotations that have been applied to this builder.
       */
      public AnnotationWorkList getApplied() {
         return applied;
      }

      /**
       * Registers the specified secondary builders with this context builder.
       *
       * <p>
       * When {@link #apply(AnnotationWorkList)} is called, it gets called on all registered builders.
       *
       * @param builders The builders to add to the list of builders.
       */
      protected void registerBuilders(Object...builders) {
         for (Object b : builders) {
            if (b == this)
               this.builders.add(b);
            else if (b instanceof Builder)
               this.builders.addAll(((Builder)b).builders);
            else
               this.builders.add(b);
         }
      }

      /**
       * Applies any of the various <ja>@XConfig</ja> annotations on the specified class to this context.
       *
       * <p>
       * Any annotations found that themselves are annotated with {@link ContextApply} will be resolved and
       * applied as properties to this builder.  These annotations include:
       * <ul class='javatreec'>
       *    <li class ='ja'>{@link BeanConfig}
       *    <li class ='ja'>{@link CsvConfig}
       *    <li class ='ja'>{@link HtmlConfig}
       *    <li class ='ja'>{@link HtmlDocConfig}
       *    <li class ='ja'>{@link JsonConfig}
       *    <li class ='ja'>{@link JsonSchemaConfig}
       *    <li class ='ja'>{@link MsgPackConfig}
       *    <li class ='ja'>{@link OpenApiConfig}
       *    <li class ='ja'>{@link ParserConfig}
       *    <li class ='ja'>{@link PlainTextConfig}
       *    <li class ='ja'>{@link SerializerConfig}
       *    <li class ='ja'>{@link SoapXmlConfig}
       *    <li class ='ja'>{@link UonConfig}
       *    <li class ='ja'>{@link UrlEncodingConfig}
       *    <li class ='ja'>{@link XmlConfig}
       *    <li class ='ja'><c>RdfConfig</c>
       * </ul>
       *
       * <p>
       * Annotations on classes are appended in the following order:
       * <ol>
       *    <li>On the package of this class.
       *    <li>On interfaces ordered parent-to-child.
       *    <li>On parent classes ordered parent-to-child.
       *    <li>On this class.
       * </ol>
       *
       * <p>
       * The default var resolver {@link VarResolver#DEFAULT} is used to resolve any variables in annotation field values.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// A class annotated with a config annotation.</jc>
       *    <ja>@BeanConfig</ja>(sortProperties=<js>"$S{sortProperties,false}"</js>)
       *    <jk>public class</jk> MyClass {...}
       *
       *    <jc>// Apply any settings found on the annotations.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .applyAnnotations(MyClass.<jk>class</jk>)
       *       .build();
       * </p>
       *
       * @param fromClasses The classes on which the annotations are defined.
       * @return This object.
       */
      @FluentSetter
      public Builder applyAnnotations(Class<?>...fromClasses) {
         AnnotationWorkList work = AnnotationWorkList.create();
         for (Class<?> c : fromClasses)
            work.add(ClassInfo.of(c).getAnnotationList(CONTEXT_APPLY_FILTER));
         return apply(work);
      }

      /**
       * Applies any of the various <ja>@XConfig</ja> annotations on the specified method to this context.
       *
       * <p>
       * Any annotations found that themselves are annotated with {@link ContextApply} will be resolved and
       * applied as properties to this builder.  These annotations include:
       * <ul class='javatreec'>
       *    <li class ='ja'>{@link BeanConfig}
       *    <li class ='ja'>{@link CsvConfig}
       *    <li class ='ja'>{@link HtmlConfig}
       *    <li class ='ja'>{@link HtmlDocConfig}
       *    <li class ='ja'>{@link JsonConfig}
       *    <li class ='ja'>{@link JsonSchemaConfig}
       *    <li class ='ja'>{@link MsgPackConfig}
       *    <li class ='ja'>{@link OpenApiConfig}
       *    <li class ='ja'>{@link ParserConfig}
       *    <li class ='ja'>{@link PlainTextConfig}
       *    <li class ='ja'>{@link SerializerConfig}
       *    <li class ='ja'>{@link SoapXmlConfig}
       *    <li class ='ja'>{@link UonConfig}
       *    <li class ='ja'>{@link UrlEncodingConfig}
       *    <li class ='ja'>{@link XmlConfig}
       *    <li class ='ja'><c>RdfConfig</c>
       * </ul>
       *
       * <p>
       * Annotations on methods are appended in the following order:
       * <ol>
       *    <li>On the package of the method class.
       *    <li>On interfaces ordered parent-to-child.
       *    <li>On parent classes ordered parent-to-child.
       *    <li>On the method class.
       *    <li>On this method and matching methods ordered parent-to-child.
       * </ol>
       *
       * <p>
       * The default var resolver {@link VarResolver#DEFAULT} is used to resolve any variables in annotation field values.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// A method annotated with a config annotation.</jc>
       *    <jk>public class</jk> MyClass {
       *       <ja>@BeanConfig</ja>(sortProperties=<js>"$S{sortProperties,false}"</js>)
       *       <jk>public void</jk> myMethod() {...}
       *    }
       *
       *    <jc>// Apply any settings found on the annotations.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .applyAnnotations(MyClass.<jk>class</jk>.getMethod(<js>"myMethod"</js>))
       *       .build();
       * </p>
       *
       * @param fromMethods The methods on which the annotations are defined.
       * @return This object.
       */
      @FluentSetter
      public Builder applyAnnotations(Method...fromMethods) {
         AnnotationWorkList work = AnnotationWorkList.create();
         for (Method m : fromMethods)
            work.add(MethodInfo.of(m).getAnnotationList(CONTEXT_APPLY_FILTER));
         return apply(work);
      }

      //-----------------------------------------------------------------------------------------------------------------
      // Properties
      //-----------------------------------------------------------------------------------------------------------------

      /**
       * Defines annotations to apply to specific classes and methods.
       *
       * <p>
       * Allows you to dynamically apply Juneau annotations typically applied directly to classes and methods.
       * Useful in cases where you want to use the functionality of the annotation on beans and bean properties but
       * do not have access to the code to do so.
       *
       * <p>
       * As a rule, any Juneau annotation with an <l>on()</l> method can be used with this setting.
       *
       * <p>
       * The following example shows the equivalent methods for applying the {@link Bean @Bean} annotation:
       * <p class='bjava'>
       *    <jc>// Class with explicit annotation.</jc>
       *    <ja>@Bean</ja>(properties=<js>"street,city,state"</js>)
       *    <jk>public class</jk> A {...}
       *
       *    <jc>// Class with annotation applied via @BeanConfig</jc>
       *    <jk>public class</jk> B {...}
       *
       *    <jc>// Java REST method with @BeanConfig annotation.</jc>
       *    <ja>@RestGet</ja>(...)
       *    <ja>@Bean</ja>(on=<js>"B"</js>, properties=<js>"street,city,state"</js>)
       *    <jk>public void</jk> doFoo() {...}
       * </p>
       *
       * <p>
       * In general, the underlying framework uses this method when it finds dynamically applied annotations on
       * config annotations.  However, concrete implementations of annotations are also provided that can be passed
       * directly into builder classes like so:
       * <p class='bjava'>
       *    <jc>// Create a concrete @Bean annotation.</jc>
       *    <ja>Bean</ja> <jv>annotation</jv> = BeanAnnotation.<jsm>create</jsm>(B.<jk>class</jk>).properties(<js>"street,city,state"</js>).build();
       *
       *    <jc>// Apply it to a serializer.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer.<jsm>create</jsm>().annotations(<jv>annotation</jv>).build();
       *
       *    <jc>// Serialize a bean with the dynamically applied annotation.</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.serialize(<jk>new</jk> B());
       * </p>
       *
       * <p>
       * The following is the list of annotations builders provided that can be constructed
       * and passed into the builder class:
       * <ul class='javatreec'>
       *    <li class='ja'>{@link org.apache.juneau.annotation.BeanAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.annotation.BeancAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.annotation.BeanIgnoreAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.annotation.BeanpAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.annotation.ExampleAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.annotation.NamePropertyAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.annotation.ParentPropertyAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.annotation.SwapAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.annotation.UriAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.csv.annotation.CsvAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.html.annotation.HtmlAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.json.annotation.JsonAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.annotation.SchemaAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.msgpack.annotation.MsgPackAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.oapi.annotation.OpenApiAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.plaintext.annotation.PlainTextAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.soap.annotation.SoapXmlAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.uon.annotation.UonAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.urlencoding.annotation.UrlEncodingAnnotation}
       *    <li class='ja'>{@link org.apache.juneau.xml.annotation.XmlAnnotation}
       * </ul>
       *
       * <p>
       * The syntax for the <l>on()</l> pattern match parameter depends on whether it applies to a class, method, field, or constructor.
       * The valid pattern matches are:
       * <ul class='spaced-list'>
       *  <li>Classes:
       *       <ul>
       *          <li>Fully qualified:
       *             <ul>
       *                <li><js>"com.foo.MyClass"</js>
       *             </ul>
       *          <li>Fully qualified inner class:
       *             <ul>
       *                <li><js>"com.foo.MyClass$Inner1$Inner2"</js>
       *             </ul>
       *          <li>Simple:
       *             <ul>
       *                <li><js>"MyClass"</js>
       *             </ul>
       *          <li>Simple inner:
       *             <ul>
       *                <li><js>"MyClass$Inner1$Inner2"</js>
       *                <li><js>"Inner1$Inner2"</js>
       *                <li><js>"Inner2"</js>
       *             </ul>
       *       </ul>
       *    <li>Methods:
       *       <ul>
       *          <li>Fully qualified with args:
       *             <ul>
       *                <li><js>"com.foo.MyClass.myMethod(String,int)"</js>
       *                <li><js>"com.foo.MyClass.myMethod(java.lang.String,int)"</js>
       *                <li><js>"com.foo.MyClass.myMethod()"</js>
       *             </ul>
       *          <li>Fully qualified:
       *             <ul>
       *                <li><js>"com.foo.MyClass.myMethod"</js>
       *             </ul>
       *          <li>Simple with args:
       *             <ul>
       *                <li><js>"MyClass.myMethod(String,int)"</js>
       *                <li><js>"MyClass.myMethod(java.lang.String,int)"</js>
       *                <li><js>"MyClass.myMethod()"</js>
       *             </ul>
       *          <li>Simple:
       *             <ul>
       *                <li><js>"MyClass.myMethod"</js>
       *             </ul>
       *          <li>Simple inner class:
       *             <ul>
       *                <li><js>"MyClass$Inner1$Inner2.myMethod"</js>
       *                <li><js>"Inner1$Inner2.myMethod"</js>
       *                <li><js>"Inner2.myMethod"</js>
       *             </ul>
       *       </ul>
       *    <li>Fields:
       *       <ul>
       *          <li>Fully qualified:
       *             <ul>
       *                <li><js>"com.foo.MyClass.myField"</js>
       *             </ul>
       *          <li>Simple:
       *             <ul>
       *                <li><js>"MyClass.myField"</js>
       *             </ul>
       *          <li>Simple inner class:
       *             <ul>
       *                <li><js>"MyClass$Inner1$Inner2.myField"</js>
       *                <li><js>"Inner1$Inner2.myField"</js>
       *                <li><js>"Inner2.myField"</js>
       *             </ul>
       *       </ul>
       *    <li>Constructors:
       *       <ul>
       *          <li>Fully qualified with args:
       *             <ul>
       *                <li><js>"com.foo.MyClass(String,int)"</js>
       *                <li><js>"com.foo.MyClass(java.lang.String,int)"</js>
       *                <li><js>"com.foo.MyClass()"</js>
       *             </ul>
       *          <li>Simple with args:
       *             <ul>
       *                <li><js>"MyClass(String,int)"</js>
       *                <li><js>"MyClass(java.lang.String,int)"</js>
       *                <li><js>"MyClass()"</js>
       *             </ul>
       *          <li>Simple inner class:
       *             <ul>
       *                <li><js>"MyClass$Inner1$Inner2()"</js>
       *                <li><js>"Inner1$Inner2()"</js>
       *                <li><js>"Inner2()"</js>
       *             </ul>
       *       </ul>
       *    <li>A comma-delimited list of anything on this list.
       * </ul>
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='ja'>{@link BeanConfig}
       * </ul>
       *
       * @param values
       *    The annotations to register with the context.
       * @return This object.
       */
      @FluentSetter
      public Builder annotations(Annotation...values) {
         annotations = addAll(annotations, values);
         return this;
      }

      /**
       * <i><l>Context</l> configuration property:&emsp;</i>  Debug mode.
       *
       * <p>
       * Enables the following additional information during serialization:
       * <ul class='spaced-list'>
       *    <li>
       *       When bean getters throws exceptions, the exception includes the object stack information
       *       in order to determine how that method was invoked.
       *    <li>
       *       Enables {@link BeanTraverseContext.Builder#detectRecursions()}.
       * </ul>
       *
       * <p>
       * Enables the following additional information during parsing:
       * <ul class='spaced-list'>
       *    <li>
       *       When bean setters throws exceptions, the exception includes the object stack information
       *       in order to determine how that method was invoked.
       * </ul>
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a serializer with debug enabled.</jc>
       *    WriterSerializer <jv>serializer</jv> = JsonSerializer
       *       .<jsm>create</jsm>()
       *       .debug()
       *       .build();
       *
       *    <jc>// Create a POJO model with a recursive loop.</jc>
       *    <jk>public class</jk> MyBean {
       *       <jk>public</jk> Object <jf>f</jf>;
       *    }
       *    MyBean <jv>bean</jv> = <jk>new</jk> MyBean();
       *    <jv>bean</jv>.<jf>f</jf> = <jv>bean</jv>;
       *
       *    <jc>// Throws a SerializeException and not a StackOverflowError</jc>
       *    String <jv>json</jv> = <jv>serializer</jv>.serialize(<jv>bean</jv>);
       * </p>
       *
       * <h5 class='section'>See Also:</h5><ul>
       *    <li class='ja'>{@link org.apache.juneau.annotation.BeanConfig#debug()}
       *    <li class='jm'>{@link org.apache.juneau.ContextSession.Builder#debug(Boolean)}
       * </ul>
       *
       * @return This object.
       */
      @FluentSetter
      public Builder debug() {
         return debug(true);
      }

      /**
       * Same as {@link #debug()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      @FluentSetter
      public Builder debug(boolean value) {
         debug = value;
         return this;
      }

      /**
       * Returns <jk>true</jk> if debug is enabled.
       *
       * @return <jk>true</jk> if debug is enabled.
       */
      public boolean isDebug() {
         return debug;
      }

      /**
       * Looks up a system property or environment variable.
       *
       * <p>
       * First looks in system properties.  Then converts the name to env-safe and looks in the system environment.
       * Then returns the default if it can't be found.
       *
       * @param <T> The type to convert to.
       * @param name The property name.
       * @param def The default value if not found.
       * @return The default value.
       */
      protected <T> T env(String name, T def) {
         return SystemEnv.env(name, def);
      }

      /**
       * Looks up a system property or environment variable.
       *
       * <p>
       * First looks in system properties.  Then converts the name to env-safe and looks in the system environment.
       * Then returns the default if it can't be found.
       *
       * @param name The property name.
       * @return The value if found.
       */
      protected Optional<String> env(String name) {
         return SystemEnv.env(name);
      }
      // <FluentSetters>

      // </FluentSetters>
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Instance
   //-----------------------------------------------------------------------------------------------------------------

   final List<Annotation> annotations;
   final boolean debug;

   private final ReflectionMap<Annotation> annotationMap;
   private final TwoKeyConcurrentCache<Class<?>,Class<? extends Annotation>,Annotation[]> classAnnotationCache;
   private final TwoKeyConcurrentCache<Class<?>,Class<? extends Annotation>,Annotation[]> declaredClassAnnotationCache;
   private final TwoKeyConcurrentCache<Method,Class<? extends Annotation>,Annotation[]> methodAnnotationCache;
   private final TwoKeyConcurrentCache<Field,Class<? extends Annotation>,Annotation[]> fieldAnnotationCache;
   private final TwoKeyConcurrentCache<Constructor<?>,Class<? extends Annotation>,Annotation[]> constructorAnnotationCache;

   /**
    * Copy constructor.
    *
    * @param copyFrom The context to copy from.
    */
   protected Context(Context copyFrom) {
      annotationMap = copyFrom.annotationMap;
      annotations = copyFrom.annotations;
      debug = copyFrom.debug;
      classAnnotationCache = copyFrom.classAnnotationCache;
      declaredClassAnnotationCache = copyFrom.declaredClassAnnotationCache;
      methodAnnotationCache = copyFrom.methodAnnotationCache;
      fieldAnnotationCache = copyFrom.fieldAnnotationCache;
      constructorAnnotationCache = copyFrom.constructorAnnotationCache;
   }

   /**
    * Constructor for this class.
    *
    * @param builder The builder for this class.
    */
   protected Context(Builder builder) {
      init(builder);
      debug = builder.debug;
      annotations = optional(builder.annotations).orElseGet(CollectionUtils::emptyList);

      ReflectionMap.Builder<Annotation> rmb = ReflectionMap.create(Annotation.class);

      annotations.forEach(a -> {
         try {
            ClassInfo ci = ClassInfo.of(a.getClass());

            MethodInfo mi = ci.getPublicMethod(x -> x.hasName("onClass"));
            if (mi != null) {
               if (! mi.getReturnType().is(Class[].class))
                  throw new ConfigException("Invalid annotation @{0} used in BEAN_annotations property.  Annotation must define an onClass() method that returns a Class array.", a.getClass().getSimpleName());
               for (Class<?> c : (Class<?>[])mi.accessible().invoke(a))
                  rmb.append(c.getName(), a);
            }

            mi = ci.getPublicMethod(x -> x.hasName("on"));
            if (mi != null) {
               if (! mi.getReturnType().is(String[].class))
                  throw new ConfigException("Invalid annotation @{0} used in BEAN_annotations property.  Annotation must define an on() method that returns a String array.", a.getClass().getSimpleName());
               for (String s : (String[])mi.accessible().invoke(a))
                  rmb.append(s, a);
            }

         } catch (Exception e) {
            throw new ConfigException(e, "Invalid annotation @{0} used in BEAN_annotations property.", className(a));
         }
      });
      this.annotationMap = rmb.build();
      boolean disabled = Boolean.getBoolean("juneau.disableAnnotationCaching");
      classAnnotationCache = new TwoKeyConcurrentCache<>(disabled, (k1,k2) -> annotationMap.appendAll(k1, k2, k1.getAnnotationsByType(k2)));
      declaredClassAnnotationCache = new TwoKeyConcurrentCache<>(disabled, (k1,k2) -> annotationMap.appendAll(k1, k2, k1.getDeclaredAnnotationsByType(k2)));
      methodAnnotationCache = new TwoKeyConcurrentCache<>(disabled, (k1,k2) -> annotationMap.appendAll(k1, k2, k1.getAnnotationsByType(k2)));
      fieldAnnotationCache = new TwoKeyConcurrentCache<>(disabled, (k1,k2) -> annotationMap.appendAll(k1, k2, k1.getAnnotationsByType(k2)));
      constructorAnnotationCache = new TwoKeyConcurrentCache<>(disabled, (k1,k2) -> annotationMap.appendAll(k1, k2, k1.getAnnotationsByType(k2)));
   }

   /**
    * Perform optional initialization on builder before it is used.
    *
    * <p>
    * Default behavior is a no-op.
    *
    * @param builder The builder to initialize.
    */
   protected void init(Builder builder) {}

   /**
    * Creates a builder from this context object.
    *
    * <p>
    * Builders are used to define new contexts (e.g. serializers, parsers) based on existing configurations.
    *
    * @return A new Builder object.
    */
   public Builder copy() {
      throw new UnsupportedOperationException("Not implemented.");
   }

   /**
    * Create a session builder based on the properties defined on this context.
    *
    * <p>
    * Use this method for creating sessions where you want to override basic settings.
    * Otherwise, use {@link #getSession()} directly.
    *
    * @return A new session builder.
    */
   public ContextSession.Builder createSession() {
      throw new UnsupportedOperationException("Not implemented.");
   }

   /**
    * Returns a session to use for this context.
    *
    * <p>
    * Note that subclasses may opt to return a reusable non-modifiable session.
    *
    * @return A new session object.
    */
   public ContextSession getSession() {
      return createSession().build();
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Properties
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Debug mode.
    *
    * @see Context.Builder#debug()
    * @return
    *    <jk>true</jk> if debug mode is enabled.
    */
   public boolean isDebug() {
      return debug;
   }

   //-----------------------------------------------------------------------------------------------------------------
   // MetaProvider methods
   //-----------------------------------------------------------------------------------------------------------------

   @Override /* MetaProvider */
   public <A extends Annotation> void forEachAnnotation(Class<A> type, Class<?> onClass, Predicate<A> filter, Consumer<A> action) {
      if (type != null && onClass != null)
         for (A a : annotations(type, onClass))
            consume(filter, action, a);
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A firstAnnotation(Class<A> type, Class<?> onClass, Predicate<A> filter) {
      if (type != null && onClass != null)
         for (A a : annotations(type, onClass))
            if (test(filter, a))
               return a;
      return null;
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A lastAnnotation(Class<A> type, Class<?> onClass, Predicate<A> filter) {
      A x = null;
      if (type != null && onClass != null)
         for (A a : annotations(type, onClass))
            if (test(filter, a))
               x = a;
      return x;
   }

   @Override /* MetaProvider */
   public <A extends Annotation> void forEachDeclaredAnnotation(Class<A> type, Class<?> onClass, Predicate<A> filter, Consumer<A> action) {
      if (type != null && onClass != null)
         for (A a : declaredAnnotations(type, onClass))
            consume(filter, action, a);
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A firstDeclaredAnnotation(Class<A> type, Class<?> onClass, Predicate<A> filter) {
      if (type != null && onClass != null)
         for (A a : declaredAnnotations(type, onClass))
            if (test(filter, a))
               return a;
      return null;
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A lastDeclaredAnnotation(Class<A> type, Class<?> onClass, Predicate<A> filter) {
      A x = null;
      if (type != null && onClass != null)
         for (A a : declaredAnnotations(type, onClass))
            if (test(filter, a))
               x = a;
      return x;
   }

   @Override /* MetaProvider */
   public <A extends Annotation> void forEachAnnotation(Class<A> type, Method onMethod, Predicate<A> filter, Consumer<A> action) {
      if (type != null && onMethod != null)
         for (A a : annotations(type, onMethod))
            consume(filter, action, a);
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A firstAnnotation(Class<A> type, Method onMethod, Predicate<A> filter) {
      if (type != null && onMethod != null)
         for (A a : annotations(type, onMethod))
            if (test(filter, a))
               return a;
      return null;
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A lastAnnotation(Class<A> type, Method onMethod, Predicate<A> filter) {
      A x = null;
      if (type != null && onMethod != null)
         for (A a : annotations(type, onMethod))
            if (test(filter, a))
               x = a;
      return x;
   }

   @Override /* MetaProvider */
   public <A extends Annotation> void forEachAnnotation(Class<A> type, Field onField, Predicate<A> filter, Consumer<A> action) {
      if (type != null && onField != null)
         for (A a : annotations(type, onField))
            consume(filter, action, a);
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A firstAnnotation(Class<A> type, Field onField, Predicate<A> filter) {
      if (type != null && onField != null)
         for (A a : annotations(type, onField))
            if (test(filter, a))
               return a;
      return null;
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A lastAnnotation(Class<A> type, Field onField, Predicate<A> filter) {
      A x = null;
      if (type != null && onField != null)
         for (A a : annotations(type, onField))
            if (test(filter, a))
               x = a;
      return x;
   }

   @Override /* MetaProvider */
   public <A extends Annotation> void forEachAnnotation(Class<A> type, Constructor<?> onConstructor, Predicate<A> filter, Consumer<A> action) {
      if (type != null && onConstructor != null)
         for (A a : annotations(type, onConstructor))
            consume(filter, action, a);
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A firstAnnotation(Class<A> type, Constructor<?> onConstructor, Predicate<A> filter) {
      if (type != null && onConstructor != null)
         for (A a : annotations(type, onConstructor))
            if (test(filter, a))
               return a;
      return null;
   }

   @Override /* MetaProvider */
   public <A extends Annotation> A lastAnnotation(Class<A> type, Constructor<?> onConstructor, Predicate<A> filter) {
      A x = null;
      if (type != null && onConstructor != null)
         for (A a : annotations(type, onConstructor))
            if (test(filter, a))
               x = a;
      return x;
   }

   /**
    * Returns <jk>true</jk> if <c>getAnnotation(a,c)</c> returns a non-null value.
    *
    * @param <A> The annotation being checked for.
    * @param type The annotation being checked for.
    * @param onClass The class being checked on.
    * @return <jk>true</jk> if the annotation exists on the specified class.
    */
   public <A extends Annotation> boolean hasAnnotation(Class<A> type, Class<?> onClass) {
      return annotations(type, onClass).length > 0;
   }

   /**
    * Returns <jk>true</jk> if <c>getAnnotation(a,m)</c> returns a non-null value.
    *
    * @param <A> The annotation being checked for.
    * @param type The annotation being checked for.
    * @param onMethod The method being checked on.
    * @return <jk>true</jk> if the annotation exists on the specified method.
    */
   public <A extends Annotation> boolean hasAnnotation(Class<A> type, Method onMethod) {
      return annotations(type, onMethod).length > 0;
   }

   /**
    * Returns <jk>true</jk> if <c>getAnnotation(a,f)</c> returns a non-null value.
    *
    * @param <A> The annotation being checked for.
    * @param type The annotation being checked for.
    * @param onField The field being checked on.
    * @return <jk>true</jk> if the annotation exists on the specified field.
    */
   public <A extends Annotation> boolean hasAnnotation(Class<A> type, Field onField) {
      return annotations(type, onField).length > 0;
   }

   /**
    * Returns <jk>true</jk> if <c>getAnnotation(a,c)</c> returns a non-null value.
    *
    * @param <A> The annotation being checked for.
    * @param type The annotation being checked for.
    * @param onConstructor The constructor being checked on.
    * @return <jk>true</jk> if the annotation exists on the specified field.
    */
   public <A extends Annotation> boolean hasAnnotation(Class<A> type, Constructor<?> onConstructor) {
      return annotations(type, onConstructor).length > 0;
   }

   @SuppressWarnings("unchecked")
   private <A extends Annotation> A[] annotations(Class<A> type, Class<?> onClass) {
      return (A[])classAnnotationCache.get(onClass, type);
   }

   @SuppressWarnings("unchecked")
   private <A extends Annotation> A[] declaredAnnotations(Class<A> type, Class<?> onClass) {
      return (A[])declaredClassAnnotationCache.get(onClass, type);
   }

   @SuppressWarnings("unchecked")
   private <A extends Annotation> A[] annotations(Class<A> type, Method onMethod) {
      return (A[])methodAnnotationCache.get(onMethod, type);
   }

   @SuppressWarnings("unchecked")
   private <A extends Annotation> A[] annotations(Class<A> type, Field onField) {
      return (A[])fieldAnnotationCache.get(onField, type);
   }

   @SuppressWarnings("unchecked")
   private <A extends Annotation> A[] annotations(Class<A> type, Constructor<?> onConstructor) {
      return (A[])constructorAnnotationCache.get(onConstructor, type);
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Other methods
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Returns the properties on this bean as a map for debugging.
    *
    * @return The properties on this bean as a map for debugging.
    */
   protected JsonMap properties() {
      return filteredMap("annotations", annotations, "debug", debug);
   }

   @Override /* Object */
   public String toString() {
      return ObjectUtils.toPropertyMap(this).asReadableString();
   }
}