/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// API class
package org.mozilla.javascript;
/**
* This is interface that all objects in JavaScript must implement.
* The interface provides for the management of properties and for
* performing conversions.
* <p>
* Host system implementors may find it easier to extend the ScriptableObject
* class rather than implementing Scriptable when writing host objects.
* <p>
* There are many static methods defined in ScriptableObject that perform
* the multiple calls to the Scriptable interface needed in order to
* manipulate properties in prototype chains.
* <p>
*
* @see org.mozilla.javascript.ScriptableObject
* @author Norris Boyd
* @author Nick Thompson
* @author Brendan Eich
*/
public interface Scriptable {
/**
* Get the name of the set of objects implemented by this Java class.
* This corresponds to the [[Class]] operation in ECMA and is used
* by Object.prototype.toString() in ECMA.<p>
* See ECMA 8.6.2 and 15.2.4.2.
*/
public String getClassName();
/**
* Value returned from <code>get</code> if the property is not
* found.
*/
public static final Object NOT_FOUND = UniqueTag.NOT_FOUND;
/**
* Get a named property from the object.
*
* Looks property up in this object and returns the associated value
* if found. Returns NOT_FOUND if not found.
* Note that this method is not expected to traverse the prototype
* chain. This is different from the ECMA [[Get]] operation.
*
* Depending on the property selector, the runtime will call
* this method or the form of <code>get</code> that takes an
* integer:
* <table>
* <tr><th>JavaScript code</th><th>Java code</th></tr>
* <tr><td>a.b </td><td>a.get("b", a)</td></tr>
* <tr><td>a["foo"] </td><td>a.get("foo", a)</td></tr>
* <tr><td>a[3] </td><td>a.get(3, a)</td></tr>
* <tr><td>a["3"] </td><td>a.get(3, a)</td></tr>
* <tr><td>a[3.0] </td><td>a.get(3, a)</td></tr>
* <tr><td>a["3.0"] </td><td>a.get("3.0", a)</td></tr>
* <tr><td>a[1.1] </td><td>a.get("1.1", a)</td></tr>
* <tr><td>a[-4] </td><td>a.get(-4, a)</td></tr>
* </table>
* <p>
* The values that may be returned are limited to the following:
* <UL>
* <LI>java.lang.Boolean objects</LI>
* <LI>java.lang.String objects</LI>
* <LI>java.lang.Number objects</LI>
* <LI>org.mozilla.javascript.Scriptable objects</LI>
* <LI>null</LI>
* <LI>The value returned by Context.getUndefinedValue()</LI>
* <LI>NOT_FOUND</LI>
* </UL>
* @param name the name of the property
* @param start the object in which the lookup began
* @return the value of the property (may be null), or NOT_FOUND
* @see org.mozilla.javascript.Context#getUndefinedValue
*/
public Object get(String name, Scriptable start);
/**
* Get a property from the object selected by an integral index.
*
* Identical to <code>get(String, Scriptable)</code> except that
* an integral index is used to select the property.
*
* @param index the numeric index for the property
* @param start the object in which the lookup began
* @return the value of the property (may be null), or NOT_FOUND
* @see org.mozilla.javascript.Scriptable#get(String,Scriptable)
*/
public Object get(int index, Scriptable start);
/**
* Indicates whether or not a named property is defined in an object.
*
* Does not traverse the prototype chain.<p>
*
* The property is specified by a String name
* as defined for the <code>get</code> method.<p>
*
* @param name the name of the property
* @param start the object in which the lookup began
* @return true if and only if the named property is found in the object
* @see org.mozilla.javascript.Scriptable#get(String, Scriptable)
* @see org.mozilla.javascript.ScriptableObject#getProperty(Scriptable, String)
*/
public boolean has(String name, Scriptable start);
/**
* Indicates whether or not an indexed property is defined in an object.
*
* Does not traverse the prototype chain.<p>
*
* The property is specified by an integral index
* as defined for the <code>get</code> method.<p>
*
* @param index the numeric index for the property
* @param start the object in which the lookup began
* @return true if and only if the indexed property is found in the object
* @see org.mozilla.javascript.Scriptable#get(int, Scriptable)
* @see org.mozilla.javascript.ScriptableObject#getProperty(Scriptable, int)
*/
public boolean has(int index, Scriptable start);
/**
* Sets a named property in this object.
* <p>
* The property is specified by a string name
* as defined for <code>get</code>.
* <p>
* The possible values that may be passed in are as defined for
* <code>get</code>. A class that implements this method may choose
* to ignore calls to set certain properties, in which case those
* properties are effectively read-only.<p>
* For properties defined in a prototype chain,
* use <code>putProperty</code> in ScriptableObject. <p>
* Note that if a property <i>a</i> is defined in the prototype <i>p</i>
* of an object <i>o</i>, then evaluating <code>o.a = 23</code> will cause
* <code>set</code> to be called on the prototype <i>p</i> with
* <i>o</i> as the <i>start</i> parameter.
* To preserve JavaScript semantics, it is the Scriptable
* object's responsibility to modify <i>o</i>. <p>
* This design allows properties to be defined in prototypes and implemented
* in terms of getters and setters of Java values without consuming slots
* in each instance.<p>
* <p>
* The values that may be set are limited to the following:
* <UL>
* <LI>java.lang.Boolean objects</LI>
* <LI>java.lang.String objects</LI>
* <LI>java.lang.Number objects</LI>
* <LI>org.mozilla.javascript.Scriptable objects</LI>
* <LI>null</LI>
* <LI>The value returned by Context.getUndefinedValue()</LI>
* </UL><p>
* Arbitrary Java objects may be wrapped in a Scriptable by first calling
* <code>Context.toObject</code>. This allows the property of a JavaScript
* object to contain an arbitrary Java object as a value.<p>
* Note that <code>has</code> will be called by the runtime first before
* <code>set</code> is called to determine in which object the
* property is defined.
* Note that this method is not expected to traverse the prototype chain,
* which is different from the ECMA [[Put]] operation.
* @param name the name of the property
* @param start the object whose property is being set
* @param value value to set the property to
* @see org.mozilla.javascript.Scriptable#has(String, Scriptable)
* @see org.mozilla.javascript.Scriptable#get(String, Scriptable)
* @see org.mozilla.javascript.ScriptableObject#putProperty(Scriptable, String, Object)
* @see org.mozilla.javascript.Context#toObject(Object, Scriptable)
*/
public void put(String name, Scriptable start, Object value);
/**
* Sets an indexed property in this object.
* <p>
* The property is specified by an integral index
* as defined for <code>get</code>.<p>
*
* Identical to <code>put(String, Scriptable, Object)</code> except that
* an integral index is used to select the property.
*
* @param index the numeric index for the property
* @param start the object whose property is being set
* @param value value to set the property to
* @see org.mozilla.javascript.Scriptable#has(int, Scriptable)
* @see org.mozilla.javascript.Scriptable#get(int, Scriptable)
* @see org.mozilla.javascript.ScriptableObject#putProperty(Scriptable, int, Object)
* @see org.mozilla.javascript.Context#toObject(Object, Scriptable)
*/
public void put(int index, Scriptable start, Object value);
/**
* Removes a property from this object.
* This operation corresponds to the ECMA [[Delete]] except that
* the no result is returned. The runtime will guarantee that this
* method is called only if the property exists. After this method
* is called, the runtime will call Scriptable.has to see if the
* property has been removed in order to determine the boolean
* result of the delete operator as defined by ECMA 11.4.1.
* <p>
* A property can be made permanent by ignoring calls to remove
* it.<p>
* The property is specified by a String name
* as defined for <code>get</code>.
* <p>
* To delete properties defined in a prototype chain,
* see deleteProperty in ScriptableObject.
* @param name the identifier for the property
* @see org.mozilla.javascript.Scriptable#get(String, Scriptable)
* @see org.mozilla.javascript.ScriptableObject#deleteProperty(Scriptable, String)
*/
public void delete(String name);
/**
* Removes a property from this object.
*
* The property is specified by an integral index
* as defined for <code>get</code>.
* <p>
* To delete properties defined in a prototype chain,
* see deleteProperty in ScriptableObject.
*
* Identical to <code>delete(String)</code> except that
* an integral index is used to select the property.
*
* @param index the numeric index for the property
* @see org.mozilla.javascript.Scriptable#get(int, Scriptable)
* @see org.mozilla.javascript.ScriptableObject#deleteProperty(Scriptable, int)
*/
public void delete(int index);
/**
* Get the prototype of the object.
* @return the prototype
*/
public Scriptable getPrototype();
/**
* Set the prototype of the object.
* @param prototype the prototype to set
*/
public void setPrototype(Scriptable prototype);
/**
* Get the parent scope of the object.
* @return the parent scope
*/
public Scriptable getParentScope();
/**
* Set the parent scope of the object.
* @param parent the parent scope to set
*/
public void setParentScope(Scriptable parent);
/**
* Get an array of property ids.
*
* Not all property ids need be returned. Those properties
* whose ids are not returned are considered non-enumerable.
*
* @return an array of Objects. Each entry in the array is either
* a java.lang.String or a java.lang.Number
*/
public Object[] getIds();
/**
* Get the default value of the object with a given hint.
* The hints are String.class for type String, Number.class for type
* Number, Scriptable.class for type Object, and Boolean.class for
* type Boolean. <p>
*
* A <code>hint</code> of null means "no hint".
*
* See ECMA 8.6.2.6.
*
* @param hint the type hint
* @return the default value
*/
public Object getDefaultValue(Class<?> hint);
/**
* The instanceof operator.
*
* <p>
* The JavaScript code "lhs instanceof rhs" causes rhs.hasInstance(lhs) to
* be called.
*
* <p>
* The return value is implementation dependent so that embedded host objects can
* return an appropriate value. See the JS 1.3 language documentation for more
* detail.
*
* <p>This operator corresponds to the proposed EMCA [[HasInstance]] operator.
*
* @param instance The value that appeared on the LHS of the instanceof
* operator
*
* @return an implementation dependent value
*/
public boolean hasInstance(Scriptable instance);
}