juneau-core/src/main/java/org/apache/juneau/ObjectMap.java

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package org.apache.juneau;

import static org.apache.juneau.internal.ClassUtils.*;

import java.io.*;
import java.util.*;

import org.apache.juneau.internal.*;
import org.apache.juneau.json.*;
import org.apache.juneau.parser.*;
import org.apache.juneau.serializer.*;
import org.apache.juneau.transform.*;
import org.apache.juneau.utils.*;

/**
 * Java implementation of a JSON object.
 * <p>
 * 	An extension of {@link LinkedHashMap}, so all methods available in that class are also available
 * 	to this class.
 * <p>
 * 	Note that the use of this class is optional.  The serializers will accept any objects that implement
 * 	the {@link java.util.Map} interface.  But this class provides some useful additional functionality
 * 	when working with JSON models constructed from Java Collections Framework objects.  For example, a
 * 	constructor is provided for converting a JSON object string directly into a {@link Map}.  It also contains
 * 	accessor methods for to avoid common typecasting when accessing elements in a list.
 *
 * <h5 class='section'>Example:</h5>
 * <p class='bcode'>
 * 	<jc>// Construct an empty Map</jc>
 * 	Map m = <jk>new</jk> ObjectMap();
 *
 * 	<jc>// Construct a Map from JSON</jc>
 * 	String json = <js>"{a:'A',b:{c:'C',d:123}}"</js>;
 * 	m = <jk>new</jk> ObjectMap(json);
 *
 * 	<jc>// Construct a Map using the append method</jc>
 * 	m = <jk>new</jk> ObjectMap().append(<js>"foo"</js>,<js>"x"</js>).append(<js>"bar"</js>,123).append(<js>"baz"</js>,<jk>true</jk>);
 *
 * 	<jc>// Construct a Map from XML generated by XmlSerializer</jc>
 * 	String xml = <js>"&lt;object&gt;&lt;a type='string'&gt;A&lt;/a&gt;&lt;b type='object'&gt;&lt;c type='string'&gt;C&lt;/c&gt;&lt;d type='number'&gt;123&lt;/d&gt;&lt;/b&gt;&lt;/object&gt;"</js>;
 * 	m = <jk>new</jk> ObjectMap(xml, DataFormat.<jsf>XML</jsf>);
 * 	m = (Map)XmlParser.<jsf>DEFAULT</jsf>.parse(xml); <jc>// Equivalent</jc>
 * 	m = (Map)XmlParser.<jsf>DEFAULT</jsf>.parse(Object.<jk>class</jk>, xml); <jc>// Equivalent</jc>
 * 	m = XmlParser.<jsf>DEFAULT</jsf>.parse(Map.<jk>class</jk>, xml); <jc>// Equivalent</jc>
 * 	m = XmlParser.<jsf>DEFAULT</jsf>.parse(ObjectMap.<jk>class</jk>, xml); <jc>// Equivalent</jc>
 *
 * 	<jc>// Construct a Map from a URL GET parameter string generated by UrlEncodingParser</jc>
 * 	String urlParams = <js>"?a='A'&amp;b={c:'C',d:123}"</js>;
 * 	m = <jk>new</jk> ObjectMap(urlParams, DataFormat.<jsf>URLPARAM</jsf>);
 * 	m = (Map)UrlEncodingParser.<jsf>DEFAULT</jsf>.parse(Object.<jk>class</jk>, xml); <jc>// Equivalent</jc>
 * 	m = UrlEncodingParser.<jsf>DEFAULT</jsf>.parse(Map.<jk>class</jk>, xml); <jc>// Equivalent</jc>
 * 	m = UrlEncodingParser.<jsf>DEFAULT</jsf>.parse(ObjectMap.<jk>class</jk>, xml); <jc>// Equivalent</jc>
 *
 * 	<jc>// Construct JSON from ObjectMap</jc>
 * 	m = <jk>new</jk> ObjectMap(<js>"{foo:'bar'},{baz:[123,true]}"</js>);
 * 	json = m.toString();  <jc>// Produces "{foo:'bar'},{baz:[123,true]}"</jc>
 * 	json = m.toString(JsonSerializer.<jsf>DEFAULT_CONDENSED</jsf>);  <jc>// Equivalent</jc>
 * 	json = JsonSerializer.<jsf>DEFAULT_CONDENSED</jsf>.serialize(m);  <jc>// Equivalent</jc>
 *
 * 	<jc>// Get a map entry as an Integer</jc>
 * 	m = <jk>new</jk> ObjectMap(<js>"{foo:123}"</js>);
 * 	Integer i = m.getInt(<js>"foo"</js>);
 * 	i = m.get(Integer.<jk>class</jk>, <js>"foo"</js>);  <jc>// Equivalent</jc>
 *
 * 	<jc>// Get a map entry as a Float</jc>
 * 	m = <jk>new</jk> ObjectMap(<js>"{foo:123}"</js>);
 * 	Float f = m.getFloat(<js>"foo"</js>);
 * 	f = m.get(Float.<jk>class</jk>, <js>"foo"</js>);  <jc>// Equivalent</jc>
 *
 * 	<jc>// Same as above, except converted to a String</jc>
 * 	m = <jk>new</jk> ObjectMap(<js>"{foo:123}"</js>);
 * 	String s = m.getString(<js>"foo"</js>); <jc>// Returns "123"</jc>
 * 	s = m.get(String.<jk>class</jk>, <js>"foo"</js>);  <jc>// Equivalent</jc>
 *
 * 	<jc>// Get one of the entries in the list as a bean (converted to a bean if it isn't already one)</jc>
 * 	m = <jk>new</jk> ObjectMap(<js>"{person:{name:'John Smith',age:45}}"</js>);
 * 	Person p = m.get(Person.<jk>class</jk>, <js>"person"</js>);
 *
 * 	<jc>// Add an inner map</jc>
 * 	ObjectMap m1 = <jk>new</jk> ObjectMap(<js>"{a:1}"</js>);
 * 	ObjectMap m2 = <jk>new</jk> ObjectMap(<js>"{b:2}"</js>).setInner(m1);
 * 	<jk>int</jk> a = m2.getInt(<js>"a"</js>);  <jc>// a == 1 </jc>
 * </p>
 * <p>
 * 	This class is not thread safe.
 * </p>
 */
public class ObjectMap extends LinkedHashMap<String,Object> {
	private static final long serialVersionUID = 1L;

	private transient BeanSession session;
	private ObjectMap inner;
	private transient PojoRest pojoRest;

	/**
	 * An empty read-only ObjectMap.
	 */
	public static final ObjectMap EMPTY_MAP = new ObjectMap() {

		private static final long serialVersionUID = 1L;

		@Override /* Map */
		@SuppressWarnings("unchecked")
		public Set<Map.Entry<String,Object>> entrySet() {
			return Collections.EMPTY_MAP.entrySet();
		}

		@Override /* Map */
		@SuppressWarnings("unchecked")
		public Set<String> keySet() {
			return Collections.EMPTY_MAP.keySet();
		}

		@Override /* Map */
		public Object put(String key, Object value) {
			throw new UnsupportedOperationException();
		}

		@Override /* Map */
		public Object remove(Object key) {
			throw new UnsupportedOperationException();
		}

		@Override /* Map */
		public Collection<Object> values() {
			return Collections.emptyMap().values();
		}
	};

	/**
	 * Construct an ObjectMap directly from a string using the specified parser.
	 *
	 * @param s The string being parsed.
	 * @param p The parser to use to parse the input.
	 * @throws ParseException If the input contains a syntax error or is malformed.
	 */
	public ObjectMap(CharSequence s, Parser p) throws ParseException {
		this(p == null ? BeanContext.DEFAULT.createSession() : p.getBeanContext().createSession());
		if (p == null)
			p = JsonParser.DEFAULT;
		if (s != null)
			p.parseIntoMap(s, this, session.string(), session.object());
	}

	/**
	 * Shortcut for <code><jk>new</jk> ObjectMap(string,JsonParser.<jsf>DEFAULT</jsf>);</code>
	 *
	 * @param s The JSON text to parse.
	 * @throws ParseException If the input contains a syntax error or is malformed.
	 */
	public ObjectMap(CharSequence s) throws ParseException {
		this(s, null);
	}

	/**
	 * Construct an ObjectMap directly from a reader using the specified parser.
	 *
	 * @param r The reader to read from.  The reader will be wrapped in a {@link BufferedReader} if it isn't already.
	 * @param p The parser to use to parse the input.
	 * @throws ParseException If the input contains a syntax error or is malformed.
	 * @throws IOException If a problem occurred trying to read from the reader.
	 */
	public ObjectMap(Reader r, Parser p) throws ParseException, IOException {
		parseReader(r, p);
	}

	/**
	 * Shortcut for <code><jk>new</jk> ObjectMap(reader, JsonParser.<jsf>DEFAULT</jsf>)</code>.
	 *
	 * @param r The reader to read from.  The reader will be wrapped in a {@link BufferedReader} if it isn't already.
	 * @throws ParseException If the input contains a syntax error or is malformed.
	 * @throws IOException If a problem occurred trying to read from the reader.
	 */
	public ObjectMap(Reader r) throws ParseException, IOException {
		parseReader(r, JsonParser.DEFAULT);
	}

	private void parseReader(Reader r, Parser p) throws ParseException {
		if (p == null)
			p = JsonParser.DEFAULT;
		p.parseIntoMap(r, this, session.string(), session.object());
	}

	/**
	 * Construct an empty JSON object (i.e. an empty {@link LinkedHashMap}).
	 */
	public ObjectMap() {
		this(BeanContext.DEFAULT.createSession());
	}

	/**
	 * Construct an empty JSON object (i.e. an empty {@link LinkedHashMap}) with the specified bean context.
	 *
	 * @param session The bean session to use for creating beans.
	 */
	public ObjectMap(BeanSession session) {
		super();
		this.session = session;
	}

	/**
	 * Construct a JSON object and fill it with the contents from the specified {@link Map}.
	 *
	 * @param m The map whose entries will be copied into this map.
	 */
	public ObjectMap(Map<?,?> m) {
		super();
		for (Map.Entry<?,?> e : m.entrySet())
			put(e.getKey().toString(), e.getValue());
	}

	/**
	 * Set an inner map in this map to allow for chained get calls.
	 * <p>
	 * If {@link #get(Object)} returns <jk>null</jk>, then {@link #get(Object)} will be called on the inner map.
	 * <p>
	 * In addition to providing the ability to chain maps, this method also provides the ability
	 * to wrap an existing map inside another map so that you can add entries to the outer
	 * map without affecting the values on the inner map.
	 * <p class='bcode'>
	 * 	ObjectMap m1 = <jk>new</jk> ObjectMap(<js>"{foo:1}"</js>);
	 * 	ObjectMap m2 = <jk>new</jk> ObjectMap().setInner(m1);
	 * 	m2.put(<js>"foo"</js>, 2);                      <jc>// Overwrite the entry</jc>
	 * 	<jk>int</jk> foo1 = m1.getInt(<js>"foo"</js>);           <jc>// foo1 == 1 </jc>
	 * 	<jk>int</jk> foo2 = m2.getInt(<js>"foo"</js>);           <jc>// foo2 == 2 </jc>
	 * </p>
	 *
	 * @param inner The inner map.
	 * 	Can be <jk>null</jk> to remove the inner map from an existing map.
	 * @return This object (for method chaining).
	 */
	public ObjectMap setInner(ObjectMap inner) {
		this.inner = inner;
		return this;
	}

	/**
	 * Searches for the specified key in this map ignoring case.
	 *
	 * @param key The key to search for.  For performance reasons, it's preferrable that the key be all lowercase.
	 * @return The key, or <jk>null</jk> if map does not contain this key.
	 */
	public String findKeyIgnoreCase(String key) {
		for (String k : keySet())
			if (key.equalsIgnoreCase(k))
				return k;
		return null;
	}


	/**
	 * Returns the inner map if one was set through {@link #setInner(ObjectMap)}.
	 *
	 * @return The inner map if one was set through {@link #setInner(ObjectMap)}, or <jk>null</jk> if no inner map is present.
	 */
	public ObjectMap getInner() {
		return inner;
	}

	/**
	 * Override the default bean session used for converting POJOs.
	 * <p>
	 * Default is {@link BeanContext#DEFAULT}, which is sufficient in most cases.
	 * <p>
	 * Useful if you're serializing/parsing beans with transforms defined.
	 *
	 * @param session The new bean session.
	 * @return This object (for method chaining).
	 */
	public ObjectMap setBeanSession(BeanSession session) {
		this.session = session;
		return this;
	}

	/**
	 * Returns the {@link BeanSession} currently associated with this map.
	 *
	 * @return The {@link BeanSession} currently associated with this map.
	 */
	public BeanSession getBeanSession() {
		return session;
	}

	/**
	 * Convenience method for adding multiple objects to this map.
	 * <p>
	 * 	Equivalent to calling {@code put(key, value)}, but returns
	 * 	this map so that the method can be chained.
	 *
	 * @param key The key.
	 * @param value The value.
	 * @return This object (for method chaining).
	 */
	public ObjectMap append(String key, Object value) {
		put(key, value);
		return this;
	}

	/**
	 * Convenience method for adding a contents of another map to this map.
	 * <p>
	 * 	Equivalent to calling {@code putAll(m)}, but returns
	 * 	this map so that the method can be chained.
	 *
	 * @param m The map whose contents should be added to this map.
	 * @return This object (for method chaining).
	 */
	public ObjectMap appendAll(Map<String,Object> m) {
		putAll(m);
		return this;
	}

	@Override /* Map */
	public Object get(Object key) {
		Object o = super.get(key);
		if (o == null && inner != null)
			o = inner.get(key);
		return o;
	}

	/**
	 * Same as {@link Map#get(Object) get()}, but returns the default value if the key
	 * could not be found.
	 *
	 * @param key The key.
	 * @param def The default value if the entry doesn't exist.
	 * @return The value, or the default value if the entry doesn't exist.
	 */
	public Object get(String key, Object def) {
		Object o = get(key);
		return (o == null ? def : o);
	}

	/**
	 * Same as {@link Map#get(Object) get()}, but casts or converts the value to the specified class type.
	 * <p>
	 * 	See {@link BeanSession#convertToType(Object, ClassMeta)} for the list of valid data conversions.
	 *
	 * @param <T> The class type.
	 * @param type The class type.
	 * @param key The key.
	 * @return The value, or <jk>null</jk> if the entry doesn't exist.
	 */
	public <T> T get(Class<T> type, String key) {
		return get(type, key, null);
	}

	/**
	 * Same as {@link Map#get(Object) get()}, but converts the raw value to the specified class type using the specified beanFilter.
	 *
	 * @param <T> The transformed class type.
	 * @param pojoSwap The swap class used to convert the raw type to a transformed type.
	 * @param key The key.
	 * @return The value, or <jk>null</jk> if the entry doesn't exist.
	 * @throws ParseException Thrown by the POJO swap if a problem occurred trying to parse the value.
	 */
	@SuppressWarnings({ "rawtypes", "unchecked" })
	public <T> T get(PojoSwap<T,?> pojoSwap, String key) throws ParseException {
		Object o = super.get(key);
		if (o == null)
			return null;
		PojoSwap swap = pojoSwap;
		return (T)swap.unswap(session, o, null);
	}

	/**
	 * Same as {@link Map#get(Object) get()}, but casts or converts the value to the specified class type.
	 * <p>
	 * 	See {@link BeanSession#convertToType(Object, ClassMeta)} for the list of valid data conversions.
	 *
	 * @param <T> The class type.
	 * @param type The class type.
	 * @param key The key.
	 * @param def The default value if the entry doesn't exist.
	 * @return The value, or the default value if the entry doesn't exist.
	 */
	public <T> T get(Class<T> type, String key, T def) {
		Object o = get(key);
		if (o == null)
			return def;
		T t = session.convertToType(o, type);
		if (t == null)
			return def;
		return t;
	}

	/**
	 * Same as {@link Map#get(Object) get()}, but casts or converts the value to the specified class type.
	 * <p>
	 * 	See {@link BeanSession#convertToType(Object, ClassMeta)} for the list of valid data conversions.
	 *
	 * @param <T> The class type.
	 * @param type The class type.
	 * @param key The key.
	 * @return The value, or the default value if the entry doesn't exist.
	 */
	public <T> T get(ClassMeta<T> type, String key) {
		return get(type, key, null);
	}

	/**
	 * Same as {@link Map#get(Object) get()}, but casts or converts the value to the specified class type.
	 * <p>
	 * 	See {@link BeanSession#convertToType(Object, ClassMeta)} for the list of valid data conversions.
	 *
	 * @param <T> The class type.
	 * @param type The class type.
	 * @param key The key.
	 * @param def The default value if the entry doesn't exist.
	 * @return The value, or the default value if the entry doesn't exist.
	 */
	public <T> T get(ClassMeta<T> type, String key, T def) {
		Object o = get(key);
		if (o == null)
			return def;
		return session.convertToType(o, type);
	}

	/**
	 * Returns the value for the first key in the list that has an entry in this map.
	 *
	 * @param keys The keys to look up in order.
	 * @return The value of the first entry whose key exists, or <jk>null</jk> if none of the keys exist in this map.
	 */
	public Object find(String...keys) {
		for (String key : keys)
			if (containsKey(key))
				return get(key);
		return null;
	}

	/**
	 * Returns the value for the first key in the list that has an entry in this map.
	 * <p>
	 * 	Casts or converts the value to the specified class type.
	 * <p>
	 * 	See {@link BeanSession#convertToType(Object, ClassMeta)} for the list of valid data conversions.
	 *
	 * @param type The class type to convert the value to.
	 * @param <T> The class type to convert the value to.
	 * @param keys The keys to look up in order.
	 * @return The value of the first entry whose key exists, or <jk>null</jk> if none of the keys exist in this map.
	 */
	public <T> T find(Class<T> type, String...keys) {
		for (String key : keys)
			if (containsKey(key))
				return get(type, key);
		return null;
	}

	/**
	 * Same as {@link #get(Class,String) get(Class,String)}, but the key is a slash-delimited
	 * 	path used to traverse entries in this POJO.
	 * <p>
	 * 	For example, the following code is equivalent:
	 * </p>
	 * <p class='bcode'>
	 * 	ObjectMap m = getObjectMap();
	 *
	 * 	<jc>// Long way</jc>
	 * 	<jk>long</jk> l = m.getObjectMap(<js>"foo"</js>).getObjectList(<js>"bar"</js>).getObjectMap(<js>"0"</js>).getLong(<js>"baz"</js>);
	 *
	 * 	<jc>// Using this method</jc>
	 * 	<jk>long</jk> l = m.getAt(<jk>long</jk>.<jk>class</jk>, <js>"foo/bar/0/baz"</js>);
	 * </p>
	 * <p>
	 * 	This method uses the {@link PojoRest} class to perform the lookup, so the map can contain
	 * 		any of the various class types that the {@link PojoRest} class supports (e.g. beans, collections, arrays).
	 * </p>
	 *
	 * @param <T> The class type.
	 * @param type The class type.
	 * @param path The path to the entry.
	 * @return The value, or <jk>null</jk> if the entry doesn't exist.
	 */
	public <T> T getAt(Class<T> type, String path) {
		return getPojoRest().get(type, path);
	}

	/**
	 * Same as <code>put(String,Object)</code>, but the key is a slash-delimited
	 * 	path used to traverse entries in this POJO.
	 * <p>
	 * 	For example, the following code is equivalent:
	 * </p>
	 * <p class='bcode'>
	 * 	ObjectMap m = getObjectMap();
	 *
	 * 	<jc>// Long way</jc>
	 * 	m.getObjectMap(<js>"foo"</js>).getObjectList(<js>"bar"</js>).getObjectMap(<js>"0"</js>).put(<js>"baz"</js>, 123);
	 *
	 * 	<jc>// Using this method</jc>
	 * 	m.putAt(<js>"foo/bar/0/baz"</js>, 123);
	 * </p>
	 * <p>
	 * 	This method uses the {@link PojoRest} class to perform the lookup, so the map can contain
	 * 		any of the various class types that the {@link PojoRest} class supports (e.g. beans, collections, arrays).
	 * </p>
	 *
	 * @param path The path to the entry.
	 * @param o The new value.
	 * @return The previous value, or <jk>null</jk> if the entry doesn't exist.
	 */
	public Object putAt(String path, Object o) {
		return getPojoRest().put(path, o);
	}

	/**
	 * Similar to {@link #putAt(String,Object) putAt(String,Object)}, but used to append
	 * 	to collections and arrays.
	 * <p>
	 * 	For example, the following code is equivalent:
	 * </p>
	 * <p class='bcode'>
	 * 	ObjectMap m = getObjectMap();
	 *
	 * 	<jc>// Long way</jc>
	 * 	m.getObjectMap(<js>"foo"</js>).getObjectList(<js>"bar"</js>).append(123);
	 *
	 * 	<jc>// Using this method</jc>
	 * 	m.postAt(<js>"foo/bar"</js>, 123);
	 * </p>
	 * <p>
	 * 	This method uses the {@link PojoRest} class to perform the lookup, so the map can contain
	 * 		any of the various class types that the {@link PojoRest} class supports (e.g. beans, collections, arrays).
	 * </p>
	 *
	 * @param path The path to the entry.
	 * @param o The new value.
	 * @return The previous value, or <jk>null</jk> if the entry doesn't exist.
	 */
	public Object postAt(String path, Object o) {
		return getPojoRest().post(path, o);
	}

	/**
	 * Similar to {@link #remove(Object) remove(Object)},but the key is a slash-delimited
	 * 	path used to traverse entries in this POJO.
	 * <p>
	 * 	For example, the following code is equivalent:
	 * </p>
	 * <p class='bcode'>
	 * 	ObjectMap m = getObjectMap();
	 *
	 * 	<jc>// Long way</jc>
	 * 	m.getObjectMap(<js>"foo"</js>).getObjectList(<js>"bar"</js>).getObjectMap(1).remove(<js>"baz"</js>);
	 *
	 * 	<jc>// Using this method</jc>
	 * 	m.deleteAt(<js>"foo/bar/0/baz"</js>);
	 * </p>
	 * <p>
	 * 	This method uses the {@link PojoRest} class to perform the lookup, so the map can contain
	 * 		any of the various class types that the {@link PojoRest} class supports (e.g. beans, collections, arrays).
	 * </p>
	 *
	 * @param path The path to the entry.
	 * @return The previous value, or <jk>null</jk> if the entry doesn't exist.
	 */
	public Object deleteAt(String path) {
		return getPojoRest().delete(path);
	}

	/**
	 * Convenience method for inserting JSON directly into an attribute on this object.
	 * <p>
	 * 	The JSON text can be an object (i.e. <js>"{...}"</js>) or an array (i.e. <js>"[...]"</js>).
	 *
	 * @param key The key.
	 * @param json The JSON text that will be parsed into an Object and then inserted into this map.
	 * @throws ParseException If the input contains a syntax error or is malformed.
	 */
	public void putJson(String key, String json) throws ParseException {
		this.put(key, JsonParser.DEFAULT.parse(json, Object.class));
	}

	/**
	 * Returns the specified entry value converted to a {@link String}.
	 * <p>
	 * 	Shortcut for <code>get(String.<jk>class</jk>, key)</code>.
	 *
	 * @param key The key.
	 * @return The converted value, or <jk>null</jk> if the map contains no mapping for this key.
	 */
	public String getString(String key) {
		return get(String.class, key);
	}

	/**
	 * Specialized method that calls {@link #getString(String)} and splits the
	 * 	results as a simple comma-delimited list.
	 *
	 * @param key the key.
	 * @return A list of tokens, trimmed of whitespace.  An empty list if entry not found.  Never <jk>null</jk>.
	 */
	public String[] getStringArray(String key) {
		String s = get(String.class, key);
		return (s == null ? new String[0] : StringUtils.split(s, ','));
	}

	/**
	 * Same as {@link #getStringArray(String)} but returns a default value if the value cannot be found.
	 *
	 * @param key The map key.
	 * @param def The default value if value is not found.
	 * @return The value converted to a string array.
	 */
	public String[] getStringArray(String key, String[] def) {
		String s = get(String.class, key);
		String[] r = (s == null ? new String[0] : StringUtils.split(s, ','));
		return (r.length == 0 ? def : r);
	}

	/**
	 * Returns the specified entry value converted to a {@link String}.
	 * <p>
	 * 	Shortcut for <code>get(String.<jk>class</jk>, key, defVal)</code>.
	 *
	 * @param key The key.
	 * @param defVal The default value if the map doesn't contain the specified mapping.
	 * @return The converted value, or the default value if the map contains no mapping for this key.
	 */
	public String getString(String key, String defVal) {
		return get(String.class, key, defVal);
	}

	/**
	 * Returns the specified entry value converted to an {@link Integer}.
	 * <p>
	 * 	Shortcut for <code>get(Integer.<jk>class</jk>, key)</code>.
	 *
	 * @param key The key.
	 * @return The converted value, or <jk>null</jk> if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Integer getInt(String key) {
		return get(Integer.class, key);
	}

	/**
	 * Returns the specified entry value converted to an {@link Integer}.
	 * <p>
	 * 	Shortcut for <code>get(Integer.<jk>class</jk>, key, defVal)</code>.
	 *
	 * @param key The key.
	 * @param defVal The default value if the map doesn't contain the specified mapping.
	 * @return The converted value, or the default value if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Integer getInt(String key, Integer defVal) {
		return get(Integer.class, key, defVal);
	}

	/**
	 * Returns the specified entry value converted to a {@link Long}.
	 * <p>
	 * 	Shortcut for <code>get(Long.<jk>class</jk>, key)</code>.
	 *
	 * @param key The key.
	 * @return The converted value, or <jk>null</jk> if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Long getLong(String key) {
		return get(Long.class, key);
	}

	/**
	 * Returns the specified entry value converted to a {@link Long}.
	 * <p>
	 * 	Shortcut for <code>get(Long.<jk>class</jk>, key, defVal)</code>.
	 *
	 * @param key The key.
	 * @param defVal The default value if the map doesn't contain the specified mapping.
	 * @return The converted value, or the default value if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Long getLong(String key, Long defVal) {
		return get(Long.class, key, defVal);
	}

	/**
	 * Returns the specified entry value converted to a {@link Boolean}.
	 * <p>
	 * 	Shortcut for <code>get(Boolean.<jk>class</jk>, key)</code>.
	 *
	 * @param key The key.
	 * @return The converted value, or <jk>null</jk> if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Boolean getBoolean(String key) {
		return get(Boolean.class, key);
	}

	/**
	 * Returns the specified entry value converted to a {@link Boolean}.
	 * <p>
	 * 	Shortcut for <code>get(Boolean.<jk>class</jk>, key, defVal)</code>.
	 *
	 * @param key The key.
	 * @param defVal The default value if the map doesn't contain the specified mapping.
	 * @return The converted value, or the default value if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Boolean getBoolean(String key, Boolean defVal) {
		return get(Boolean.class, key, defVal);
	}

	/**
	 * Returns the specified entry value converted to a {@link Map}.
	 * <p>
	 * 	Shortcut for <code>get(Map.<jk>class</jk>, key)</code>.
	 *
	 * @param key The key.
	 * @return The converted value, or <jk>null</jk> if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Map<?,?> getMap(String key) {
		return get(Map.class, key);
	}

	/**
	 * Returns the specified entry value converted to a {@link Map}.
	 * <p>
	 * 	Shortcut for <code>get(Map.<jk>class</jk>, key, defVal)</code>.
	 *
	 * @param key The key.
	 * @param defVal The default value if the map doesn't contain the specified mapping.
	 * @return The converted value, or the default value if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Map<?,?> getMap(String key, Map<?,?> defVal) {
		return get(Map.class, key, defVal);
	}

	/**
	 * Returns the specified entry value converted to a {@link List}.
	 * <p>
	 * 	Shortcut for <code>get(List.<jk>class</jk>, key)</code>.
	 *
	 * @param key The key.
	 * @return The converted value, or <jk>null</jk> if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public List<?> getList(String key) {
		return get(List.class, key);
	}

	/**
	 * Returns the specified entry value converted to a {@link List}.
	 * <p>
	 * 	Shortcut for <code>get(List.<jk>class</jk>, key, defVal)</code>.
	 *
	 * @param key The key.
	 * @param defVal The default value if the map doesn't contain the specified mapping.
	 * @return The converted value, or the default value if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public List<?> getList(String key, List<?> defVal) {
		return get(List.class, key, defVal);
	}

	/**
	 * Returns the specified entry value converted to a {@link Map}.
	 * <p>
	 * 	Shortcut for <code>get(ObjectMap.<jk>class</jk>, key)</code>.
	 *
	 * @param key The key.
	 * @return The converted value, or <jk>null</jk> if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public ObjectMap getObjectMap(String key) {
		return get(ObjectMap.class, key);
	}

	/**
	 * Returns the specified entry value converted to a {@link ObjectMap}.
	 * <p>
	 * 	Shortcut for <code>get(ObjectMap.<jk>class</jk>, key, defVal)</code>.
	 *
	 * @param key The key.
	 * @param defVal The default value if the map doesn't contain the specified mapping.
	 * @return The converted value, or the default value if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public ObjectMap getObjectMap(String key, ObjectMap defVal) {
		return get(ObjectMap.class, key, defVal);
	}

	/**
	 * Returns the specified entry value converted to a {@link ObjectList}.
	 * <p>
	 * 	Shortcut for <code>get(ObjectList.<jk>class</jk>, key)</code>.
	 *
	 * @param key The key.
	 * @return The converted value, or <jk>null</jk> if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public ObjectList getObjectList(String key) {
		return get(ObjectList.class, key);
	}

	/**
	 * Returns the specified entry value converted to a {@link ObjectList}.
	 * <p>
	 * 	Shortcut for <code>get(ObjectList.<jk>class</jk>, key, defVal)</code>.
	 *
	 * @param key The key.
	 * @param defVal The default value if the map doesn't contain the specified mapping.
	 * @return The converted value, or the default value if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public ObjectList getObjectList(String key, ObjectList defVal) {
		return get(ObjectList.class, key, defVal);
	}

	/**
	 * Returns the first entry that exists converted to a {@link String}.
	 * <p>
	 * 	Shortcut for <code>find(String.<jk>class</jk>, keys)</code>.
	 *
	 * @param keys The list of keys to look for.
	 * @return The converted value of the first key in the list that has an entry in this map,
	 * 	or <jk>null</jk> if the map contains no mapping for any of the keys.
	 */
	public String findString(String... keys) {
		return find(String.class, keys);
	}

	/**
	 * Returns the first entry that exists converted to an {@link Integer}.
	 * <p>
	 * 	Shortcut for <code>find(Integer.<jk>class</jk>, keys)</code>.
	 *
	 * @param keys The list of keys to look for.
	 * @return The converted value of the first key in the list that has an entry in this map,
	 * 	or <jk>null</jk> if the map contains no mapping for any of the keys.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Integer findInt(String... keys) {
		return find(Integer.class, keys);
	}

	/**
	 * Returns the first entry that exists converted to a {@link Long}.
	 * <p>
	 * 	Shortcut for <code>find(Long.<jk>class</jk>, keys)</code>.
	 *
	 * @param keys The list of keys to look for.
	 * @return The converted value of the first key in the list that has an entry in this map,
	 * 	or <jk>null</jk> if the map contains no mapping for any of the keys.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Long findLong(String... keys) {
		return find(Long.class, keys);
	}

	/**
	 * Returns the first entry that exists converted to a {@link Boolean}.
	 * <p>
	 * 	Shortcut for <code>find(Boolean.<jk>class</jk>, keys)</code>.
	 *
	 * @param keys The list of keys to look for.
	 * @return The converted value of the first key in the list that has an entry in this map,
	 * 	or <jk>null</jk> if the map contains no mapping for any of the keys.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Boolean findBoolean(String... keys) {
		return find(Boolean.class, keys);
	}

	/**
	 * Returns the first entry that exists converted to a {@link Map}.
	 * <p>
	 * 	Shortcut for <code>find(Map.<jk>class</jk>, keys)</code>.
	 *
	 * @param keys The list of keys to look for.
	 * @return The converted value of the first key in the list that has an entry in this map,
	 * 	or <jk>null</jk> if the map contains no mapping for any of the keys.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public Map<?,?> findMap(String... keys) {
		return find(Map.class, keys);
	}

	/**
	 * Returns the first entry that exists converted to a {@link List}.
	 * <p>
	 * 	Shortcut for <code>find(List.<jk>class</jk>, keys)</code>.
	 *
	 * @param keys The list of keys to look for.
	 * @return The converted value of the first key in the list that has an entry in this map,
	 * 	or <jk>null</jk> if the map contains no mapping for any of the keys.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public List<?> findList(String... keys) {
		return find(List.class, keys);
	}

	/**
	 * Returns the first entry that exists converted to a {@link ObjectMap}.
	 * <p>
	 * 	Shortcut for <code>find(ObjectMap.<jk>class</jk>, keys)</code>.
	 *
	 * @param keys The list of keys to look for.
	 * @return The converted value of the first key in the list that has an entry in this map,
	 * 	or <jk>null</jk> if the map contains no mapping for any of the keys.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public ObjectMap findObjectMap(String... keys) {
		return find(ObjectMap.class, keys);
	}

	/**
	 * Returns the first entry that exists converted to a {@link ObjectList}.
	 * <p>
	 * 	Shortcut for <code>find(ObjectList.<jk>class</jk>, keys)</code>.
	 *
	 * @param keys The list of keys to look for.
	 * @return The converted value of the first key in the list that has an entry in this map,
	 * 	or <jk>null</jk> if the map contains no mapping for any of the keys.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public ObjectList findObjectList(String... keys) {
		return find(ObjectList.class, keys);
	}

	/**
	 * Returns the first key in the map.
	 *
	 * @return The first key in the map, or <jk>null</jk> if the map is empty.
	 */
	public String getFirstKey() {
		return isEmpty() ? null : keySet().iterator().next();
	}

	/**
	 * Returns the class type of the object at the specified index.
	 *
	 * @param key The key into this map.
	 * @return The data type of the object at the specified key, or <jk>null</jk> if the value is null or does not exist.
	 */
	public ClassMeta<?> getClassMeta(String key) {
		return session.getClassMetaForObject(get(key));
	}

	/**
	 * Equivalent to calling <code>get(class,key,def)</code> followed by <code>remove(key);</code>
	 *
	 * @param <T> The class type.
	 * @param type The class type.
	 * @param key The key.
	 * @param defVal The default value if the map doesn't contain the specified mapping.
	 * @return The converted value, or the default value if the map contains no mapping for this key.
	 * @throws InvalidDataConversionException If value cannot be converted.
	 */
	public <T> T remove(Class<T> type, String key, T defVal) {
		T t = get(type, key, defVal);
		remove(key);
		return t;
	}


	/**
	 * Convenience method for removing several keys at once.
	 *
	 * @param keys The list of keys to remove.
	 */
	public void removeAll(Collection<String> keys) {
		for (String k : keys)
			remove(k);
	}

	/**
	 * Convenience method for removing several keys at once.
	 *
	 * @param keys The list of keys to remove.
	 */
	public void removeAll(String... keys) {
		for (String k : keys)
			remove(k);
	}

	@Override /* Map */
	public boolean containsKey(Object key) {
		if (super.containsKey(key))
			return true;
		if (inner != null)
			return inner.containsKey(key);
		return false;
	}

	/**
	 * Returns <jk>true</jk> if this map contains the specified key, ignoring
	 * 	the inner map if it exists.
	 *
	 * @param key The key to look up.
	 * @return <jk>true</jk> if this map contains the specified key.
	 */
	public boolean containsOuterKey(Object key) {
		return super.containsKey(key);
	}

	/**
	 * Returns a copy of this <code>ObjectMap</code> with only the specified keys.
	 *
	 * @param keys The keys of the entries to copy.
	 * @return A new map with just the keys and values from this map.
	 */
	public ObjectMap include(String...keys) {
		ObjectMap m2 = new ObjectMap();
		for (Map.Entry<String,Object> e : this.entrySet())
			for (String k : keys)
				if (k.equals(e.getKey()))
					m2.put(k, e.getValue());
		return m2;
	}

	/**
	 * Returns a copy of this <code>ObjectMap</code> without the specified keys.
	 *
	 * @param keys The keys of the entries not to copy.
	 * @return A new map without the keys and values from this map.
	 */
	public ObjectMap exclude(String...keys) {
		ObjectMap m2 = new ObjectMap();
		for (Map.Entry<String,Object> e : this.entrySet()) {
			boolean exclude = false;
			for (String k : keys)
				if (k.equals(e.getKey()))
					exclude = true;
			if (! exclude)
				m2.put(e.getKey(), e.getValue());
		}
		return m2;
	}

	/**
	 * Sets a value in this map if the entry does not exist or the value is <jk>null</jk>.
	 *
	 * @param key The map key.
	 * @param val The value to set if the current value does not exist or is <jk>null</jk>.
	 * @return This object (for method chaining).
	 */
	public ObjectMap putIfNull(String key, Object val) {
		Object o = get(key);
		if (o == null)
			put(key, val);
		return this;
	}

	/**
	 * Sets a value in this map if the entry does not exist or the value is <jk>null</jk> or an empty string.
	 *
	 * @param key The map key.
	 * @param val The value to set if the current value does not exist or is <jk>null</jk> or an empty string.
	 * @return This object (for method chaining).
	 */
	public ObjectMap putIfEmpty(String key, Object val) {
		Object o = get(key);
		if (o == null || o.toString().isEmpty())
			put(key, val);
		return this;
	}

	/**
	 * Converts this map into the class type specified by the <js>"_type"</js> entry value.
	 * <p>
	 * TODO - Needs better description.
	 *
	 * @return This object map cast as another object.
	 */
	public Object cast() {
		return cast(session.getBeanRegistry());
	}

	/**
	 * Same as {@link #cast()}, but first do a lookup for the name in the specified dictionary.
	 *
	 * @param beanRegistry
	 * 	The class lexicon to resolve the name.  Can be <jk>null</jk>.
	 * @return The new Java object of type specified by the <js>"_type"</js> entry value, or this
	 * 	same object if entry does not exist.
	 */
	public Object cast(BeanRegistry beanRegistry) {
		String c = (String)get(session.getBeanTypePropertyName());
		if (c == null || beanRegistry == null)
			return this;
		ClassMeta<?> cm = beanRegistry.getClassMeta(c);
		if (cm == null)
			return this;
		return cast2(cm);
	}

	/**
	 * Converts this map into an object of the specified type.
	 * <p>
	 * The rules are the same as those specified in {@link #cast()}.
	 * <p>
	 * If this map contains a <js>"_type"</js> entry, it must be the same as or a subclass
	 * 	of the <code>type</code>.
	 *
	 * @param <T> The class type to convert this map object to.
	 * @param type The class type to convert this map object to.
	 * @return The new object.
	 * @throws ClassCastException If the <js>"_type"</js> entry is present and not assignable
	 * 	from <code>type</code>
	 */
	@SuppressWarnings("unchecked")
	public <T> T cast(Class<T> type) {
		ClassMeta<?> c1 = session.getBeanRegistry().getClassMeta((String)get(session.getBeanTypePropertyName()));
		ClassMeta<?> c2 = session.getClassMeta(type);
		ClassMeta<?> c = narrowClassMeta(c1, c2);
		return (T)cast2(c);
	}

	/**
	 * Same as {@link #cast(Class)}, except allows you to specify a {@link ClassMeta} parameter.
	 *
	 * @param <T> The class type to convert this map object to.
	 * @param cm The class type to convert this map object to.
	 * @return The new object.
	 * @throws ClassCastException If the <js>"_type"</js> entry is present and not assignable
	 * 	from <code>type</code>
	 */
	@SuppressWarnings({"unchecked"})
	public <T> T cast(ClassMeta<T> cm) {
		ClassMeta<?> c1 = session.getBeanRegistry().getClassMeta((String)get(session.getBeanTypePropertyName()));
		ClassMeta<?> c = narrowClassMeta(c1, cm);
		return (T)cast2(c);
	}

	/*
	 * Combines the class specified by a "_type" attribute with the ClassMeta
	 * passed in through the cast(ClassMeta) method.
	 * The rule is that child classes superceed parent classes, and c2 superceeds c1
	 * if one isn't the parent of another.
	 */
	private ClassMeta<?> narrowClassMeta(ClassMeta<?> c1, ClassMeta<?> c2) {
		if (c1 == null)
			return c2;
		ClassMeta<?> c = getNarrowedClassMeta(c1, c2);
		if (c1.isMap()) {
			ClassMeta<?> k = getNarrowedClassMeta(c1.getKeyType(), c2.getKeyType());
			ClassMeta<?> v = getNarrowedClassMeta(c1.getValueType(), c2.getValueType());
			return session.getClassMeta(c.getInnerClass(), k, v);
		}
		if (c1.isCollection()) {
			ClassMeta<?> e = getNarrowedClassMeta(c1.getElementType(), c2.getElementType());
			return session.getClassMeta(c.getInnerClass(), e);
		}
		return c;
	}

	/*
	 * If c1 is a child of c2 or the same as c2, returns c1.
	 * Otherwise, returns c2.
	 */
	private ClassMeta<?> getNarrowedClassMeta(ClassMeta<?> c1, ClassMeta<?> c2) {
		if (isParentClass(c2.getInnerClass(), c1.getInnerClass()))
			return c1;
		return c2;
	}

	/*
	 * Converts this map to the specified class type.
	 */
	@SuppressWarnings({"unchecked","rawtypes"})
	private <T> T cast2(ClassMeta<T> cm) {

		try {
			Object value = get("value");

			if (cm.isMap()) {
				Map m2 = (cm.canCreateNewInstance() ? (Map)cm.newInstance() : new ObjectMap(session));
				ClassMeta<?> kType = cm.getKeyType(), vType = cm.getValueType();
				for (Map.Entry<String,Object> e : entrySet()) {
					Object k = e.getKey();
					Object v = e.getValue();
					if (! k.equals(session.getBeanTypePropertyName())) {

						// Attempt to recursively cast child maps.
						if (v instanceof ObjectMap)
							v = ((ObjectMap)v).cast(session.getBeanRegistry());

						k = (kType.isString() ? k : session.convertToType(k, kType));
						v = (vType.isObject() ? v : session.convertToType(v, vType));

						m2.put(k, v);
					}
				}
				return (T)m2;

			} else if (cm.isBean()) {
				BeanMap<? extends T> bm = session.newBeanMap(cm.getInnerClass());

				// Iterate through all the entries in the map and set the individual field values.
				for (Map.Entry<String,Object> e : entrySet()) {
					String k = e.getKey();
					Object v = e.getValue();
					if (! k.equals(session.getBeanTypePropertyName())) {

						// Attempt to recursively cast child maps.
						if (v instanceof ObjectMap)
							v = ((ObjectMap)v).cast(session.getBeanRegistry());

						bm.put(k, v);
					}
				}

				return bm.getBean();

			} else if (cm.isCollectionOrArray()) {
				List items = (List)get("items");
				return session.convertToType(items, cm);

			} else if (value != null) {
				return session.convertToType(value, cm);
			}

		} catch (Exception e) {
			throw new BeanRuntimeException(cm.innerClass, "Error occurred attempting to cast to an object of type ''{0}''", cm.innerClass.getName()).initCause(e);
		}

		throw new BeanRuntimeException(cm.innerClass, "Cannot convert to class type ''{0}''.  Only beans and maps can be converted using this method.", cm.innerClass.getName());
	}

	private PojoRest getPojoRest() {
		if (pojoRest == null)
			pojoRest = new PojoRest(this);
		return pojoRest;
	}

	/**
	 * Serialize this object into a string using the specified serializer.
	 *
	 * @param serializer The serializer to use to convert this object to a string.
	 * @return This object serialized as a string.
	 * @throws SerializeException If a problem occurred trying to convert the output.
	 */
	public String toString(WriterSerializer serializer) throws SerializeException {
		return serializer.serialize(this);
	}

	/**
	 * Serialize this object into a JSON string using the {@link JsonSerializer#DEFAULT} serializer.
	 */
	@Override /* Object */
	public String toString() {
		try {
			return this.toString(JsonSerializer.DEFAULT_LAX);
		} catch (SerializeException e) {
			return e.getLocalizedMessage();
		}
	}

	/**
	 * Convenience method for serializing this map to the specified <code>Writer</code> using
	 * the {@link JsonSerializer#DEFAULT} serializer.
	 *
	 * @param w The writer to serialize this object to.
	 * @return This object (for method chaining).
	 * @throws IOException If a problem occurred trying to write to the writer.
	 * @throws SerializeException If a problem occurred trying to convert the output.
	 */
	public ObjectMap serializeTo(Writer w) throws IOException, SerializeException {
		JsonSerializer.DEFAULT.serialize(this);
		return this;
	}

	@Override /* Map */
	public Set<String> keySet() {
		if (inner == null)
			return super.keySet();
		LinkedHashSet<String> s = new LinkedHashSet<String>();
		s.addAll(inner.keySet());
		s.addAll(super.keySet());
		return s;
	}

	@Override /* Map */
	public Set<Map.Entry<String,Object>> entrySet() {
		if (inner == null)
			return super.entrySet();

		final Set<String> keySet = keySet();
		final Iterator<String> keys = keySet.iterator();

		return new AbstractSet<Map.Entry<String,Object>>() {

			@Override /* Iterable */
			public Iterator<Map.Entry<String,Object>> iterator() {

				return new Iterator<Map.Entry<String,Object>>() {

					@Override /* Iterator */
					public boolean hasNext() {
						return keys.hasNext();
					}

					@Override /* Iterator */
					public Map.Entry<String,Object> next() {
						return new Map.Entry<String,Object>() {
							String key = keys.next();

							@Override /* Map.Entry */
							public String getKey() {
								return key;
							}

							@Override /* Map.Entry */
							public Object getValue() {
								return get(key);
							}

							@Override /* Map.Entry */
							public Object setValue(Object object) {
								return put(key, object);
							}
						};
					}

					@Override /* Iterator */
					public void remove() {
						throw new UnsupportedOperationException();
					}
				};
			}

			@Override /* Set */
			public int size() {
				return keySet.size();
			}
		};
	}
}