hu.akarnokd.reactive4java.util

Class Lambdas

java.lang.Object

hu.akarnokd.reactive4java.util.Lambdas

public final class Lambdas
extends java.lang.Object

Utility class to create functions which have their body as Javascript (or other script) language.

Note that scripting performance is typically 10-100 slower than the same JIT compiled Java expression.

See the scripting articles about how to script in java.

Note that a script engines might not be thread safe, e.g., you might not run multiple scripts without external synchronization. See also THREADING for further details.

Method Summary

Modifier and Type	Method and Description
static Action0	action0(java.lang.String expression, javax.script.ScriptEngine engine, java.util.Map<java.lang.String,java.lang.Object> bindings) Returns a parameterless action which invokes the given script on the script engine.
static Action0	action0(java.lang.String expression, javax.script.ScriptEngine engine, java.lang.Object... nameThenObject) Creates a parameterless action which executes the given script with the given script engine.
static <T> Action1<T>	action1(java.lang.String expression, javax.script.ScriptEngine engine, java.util.Map<java.lang.String,java.lang.Object> bindings) Creates a single parameter action which invokes the script engine with a given expression.
static <T> Action1<T>	action1(java.lang.String expression, javax.script.ScriptEngine engine, java.lang.Object... nameThenObject) Creates a single parameter action which executes the given script on the script engine.
static Action0	as0(java.lang.String expression, java.util.Map<java.lang.String,java.lang.Object> bindings) Creates a parameterless action which executes the given script as JavaScript.
static Action0	as0(java.lang.String expression, java.lang.Object... nameThenObject) Creates a parameterless action which executes the given script as javascript.
static <T> Action1<T>	as1(java.lang.String expression, java.util.Map<java.lang.String,java.lang.Object> bindings) Creates a single parameter action which executes the given script as JavaScript.
static <T> Action1<T>	as1(java.lang.String expression, java.lang.Object... nameThenObject) Creates a single parameter action which executes the given script as JavaScript.
static javax.script.ScriptEngine	getEngine(java.lang.String name) Retrieve a script engine for the given name.
static <T> Func0<T>	js0(java.lang.String expression) Returns a parameterless function which invokes the given javascript and retunrs its value.
static <T> Func0<T>	js0(java.lang.String expression, java.util.Map<java.lang.String,java.lang.Object> bindings) Returns a parameterless function which invokes the given javascript and retunrs its value.
static <T> Func0<T>	js0(java.lang.String expression, java.lang.Object... nameThenObject) Creates a parameterless function which executes the given script as javascript.
static <T,U> Func1<T,U>	js1(java.lang.String expression) Creates a single parameter function which invokes the script engine with a given expression and returns its result.
static <T,U> Func1<T,U>	js1(java.lang.String expression, java.util.Map<java.lang.String,java.lang.Object> bindings) Creates a single parameter function which invokes the script engine with a given expression and returns its result.
static <T,U> Func1<T,U>	js1(java.lang.String expression, java.lang.Object... nameThenObject) Creates a single parameter function which executes the given script as javascript.
static <T,U,V> Func2<T,U,V>	js2(java.lang.String expression) Creates a two parameter function which invokes the script engine with a given expression and returns its result.
static <T,U,V> Func2<T,U,V>	js2(java.lang.String expression, java.util.Map<java.lang.String,java.lang.Object> bindings) Creates a two parameter function which invokes the script engine with a given expression and returns its result.
static <T,U,V> Func2<T,U,V>	js2(java.lang.String expression, java.lang.Object... nameThenObject) Creates a two parameter function which executes the given script as javascript.
static <T> Func0<T>	script0(java.lang.String expression, javax.script.ScriptEngine engine, java.util.Map<java.lang.String,java.lang.Object> bindings) Returns a parameterless function which invokes the given script on the script engine and retunrs its value.
static <T> Func0<T>	script0(java.lang.String expression, javax.script.ScriptEngine engine, java.lang.Object... nameThenObject) Creates a parameterless function which executes the given script as javascript.
static <T,U> Func1<U,T>	script1(java.lang.String expression, javax.script.ScriptEngine engine, java.util.Map<java.lang.String,java.lang.Object> bindings) Creates a single parameter function which invokes the script engine with a given expression and returns its result.
static <T,U> Func1<T,U>	script1(java.lang.String expression, javax.script.ScriptEngine engine, java.lang.Object... nameThenObject) Creates a single parameter function which executes the given script as javascript.
static <T,U,V> Func2<U,V,T>	script2(java.lang.String expression, javax.script.ScriptEngine engine, java.util.Map<java.lang.String,java.lang.Object> bindings) Creates a two parameter function which invokes the script engine with a given expression and returns its result.
static <T,U,V> Func2<T,U,V>	script2(java.lang.String expression, javax.script.ScriptEngine engine, java.lang.Object... nameThenObject) Creates a two parameter function which executes the given script as javascript.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

action0

@Nonnull
public static Action0 action0(@Nonnull
                                        java.lang.String expression,
                                        @Nonnull
                                        javax.script.ScriptEngine engine,
                                        @Nonnull
                                        java.util.Map<java.lang.String,java.lang.Object> bindings)

Returns a parameterless action which invokes the given script on the script engine.

The syntax of the expression follows the generic lambda format used throughout this utility class:

=> expression1; expression;

You may omit the => completely.

Parameters:

expression - the original lambda expression

engine - the script engine to use

bindings - the external resources the script might need

Returns:

the function

action0

@Nonnull
public static Action0 action0(@Nonnull
                                        java.lang.String expression,
                                        @Nonnull
                                        javax.script.ScriptEngine engine,
                                        @Nonnull
                                        java.lang.Object... nameThenObject)

Creates a parameterless action which executes the given script with the given script engine. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Parameters:

expression - the lambda expression

engine - the scripting engine to use

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function

action1

@Nonnull
public static <T> Action1<T> action1(@Nonnull
                                               java.lang.String expression,
                                               @Nonnull
                                               javax.script.ScriptEngine engine,
                                               @Nonnull
                                               java.util.Map<java.lang.String,java.lang.Object> bindings)

Creates a single parameter action which invokes the script engine with a given expression.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression;

Type Parameters:

T - the parameter type of the action

Parameters:

expression - the lambda expression

engine - the engine to run the expression

bindings - the external resources the script might need

Returns:

the function

action1

@Nonnull
public static <T> Action1<T> action1(@Nonnull
                                               java.lang.String expression,
                                               @Nonnull
                                               javax.script.ScriptEngine engine,
                                               @Nonnull
                                               java.lang.Object... nameThenObject)

Creates a single parameter action which executes the given script on the script engine. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the parameter type of the action

Parameters:

expression - the lambda expression

engine - the script engine to use

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function

as0

@Nonnull
public static Action0 as0(@Nonnull
                                    java.lang.String expression,
                                    @Nonnull
                                    java.util.Map<java.lang.String,java.lang.Object> bindings)

Creates a parameterless action which executes the given script as JavaScript.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Parameters:

expression - the lambda expression

bindings - the extra parameter bingings

Returns:

the function

as0

@Nonnull
public static Action0 as0(@Nonnull
                                    java.lang.String expression,
                                    @Nonnull
                                    java.lang.Object... nameThenObject)

Creates a parameterless action which executes the given script as javascript. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Parameters:

expression - the lambda expression

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function

as1

@Nonnull
public static <T> Action1<T> as1(@Nonnull
                                           java.lang.String expression,
                                           @Nonnull
                                           java.util.Map<java.lang.String,java.lang.Object> bindings)

Creates a single parameter action which executes the given script as JavaScript.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the parameter type of the action

Parameters:

expression - the lambda expression

bindings - the extra parameter bindings

Returns:

the function

as1

@Nonnull
public static <T> Action1<T> as1(@Nonnull
                                           java.lang.String expression,
                                           @Nonnull
                                           java.lang.Object... nameThenObject)

Creates a single parameter action which executes the given script as JavaScript. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the parameter type of the action

Parameters:

expression - the lambda expression

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function

getEngine

@Nonnull
public static javax.script.ScriptEngine getEngine(@Nonnull
                                                            java.lang.String name)

Retrieve a script engine for the given name. This method is equivalent to new ScriptEngineManager().getEngineByName(name) call. Might throw an IllegalArgumentException if there is no such engine by the name.

Parameters:

name - the script engine name. For javascript, you may use js.

Returns:

the script engine

js0

@Nonnull
public static <T> Func0<T> js0(@Nonnull
                                         java.lang.String expression)

Returns a parameterless function which invokes the given javascript and retunrs its value.

The syntax of the expression follows the generic lambda format used throughout this utility class:

=> expression1; expression; return result

For zero parameters, you may omit the => completely.

Type Parameters:

T - the return type of the function

Parameters:

expression - the lambda expression

Returns:

the function

js0

@Nonnull
public static <T> Func0<T> js0(@Nonnull
                                         java.lang.String expression,
                                         @Nonnull
                                         java.util.Map<java.lang.String,java.lang.Object> bindings)

Returns a parameterless function which invokes the given javascript and retunrs its value.

The syntax of the expression follows the generic lambda format used throughout this utility class:

=> expression1; expression; return result

For zero parameters, you may omit the => completely.

Type Parameters:

T - the return type of the function

Parameters:

expression - the lambda expression

bindings - the external resources the script might need

Returns:

the function

js0

@Nonnull
public static <T> Func0<T> js0(@Nonnull
                                         java.lang.String expression,
                                         @Nonnull
                                         java.lang.Object... nameThenObject)

Creates a parameterless function which executes the given script as javascript. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the result type

Parameters:

expression - the lambda expression

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function

js1

@Nonnull
public static <T,U> Func1<T,U> js1(@Nonnull
                                             java.lang.String expression)

Creates a single parameter function which invokes the script engine with a given expression and returns its result.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the result type of the function

U - the parameter type

Parameters:

expression - the lambda expression

Returns:

the function

js1

@Nonnull
public static <T,U> Func1<T,U> js1(@Nonnull
                                             java.lang.String expression,
                                             @Nonnull
                                             java.util.Map<java.lang.String,java.lang.Object> bindings)

Creates a single parameter function which invokes the script engine with a given expression and returns its result.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the result type of the function

U - the parameter type

Parameters:

expression - the lambda expression

bindings - the external resources the script might need

Returns:

the function

js1

@Nonnull
public static <T,U> Func1<T,U> js1(@Nonnull
                                             java.lang.String expression,
                                             @Nonnull
                                             java.lang.Object... nameThenObject)

Creates a single parameter function which executes the given script as javascript. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the result type

U - the parameter type of the function

Parameters:

expression - the lambda expression

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function

js2

@Nonnull
public static <T,U,V> Func2<T,U,V> js2(@Nonnull
                                                 java.lang.String expression)

Creates a two parameter function which invokes the script engine with a given expression and returns its result.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName1, paramName2 => expression1; expression; return result;

Type Parameters:

T - the result type of the function

U - the first parameter type

V - the second parameter type

Parameters:

expression - the lambda expression

Returns:

the function

js2

@Nonnull
public static <T,U,V> Func2<T,U,V> js2(@Nonnull
                                                 java.lang.String expression,
                                                 @Nonnull
                                                 java.util.Map<java.lang.String,java.lang.Object> bindings)

Creates a two parameter function which invokes the script engine with a given expression and returns its result.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName1, paramName2 => expression1; expression; return result;

Type Parameters:

T - the result type of the function

U - the first parameter type

V - the second parameter type

Parameters:

expression - the lambda expression

bindings - the external resources the script might need

Returns:

the function

js2

@Nonnull
public static <T,U,V> Func2<T,U,V> js2(@Nonnull
                                                 java.lang.String expression,
                                                 @Nonnull
                                                 java.lang.Object... nameThenObject)

Creates a two parameter function which executes the given script as javascript. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the result type

U - the first parameter type

V - the second parameter type

Parameters:

expression - the lambda expression

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function

script0

@Nonnull
public static <T> Func0<T> script0(@Nonnull
                                             java.lang.String expression,
                                             @Nonnull
                                             javax.script.ScriptEngine engine,
                                             @Nonnull
                                             java.util.Map<java.lang.String,java.lang.Object> bindings)

Returns a parameterless function which invokes the given script on the script engine and retunrs its value.

The syntax of the expression follows the generic lambda format used throughout this utility class:

param1, param2 => expression1; expression; return result

For zero parameters, you may omit the => completely.

Type Parameters:

T - the return type of the function

Parameters:

expression - the original lambda expression

engine - the script engine to use

bindings - the external resources the script might need

Returns:

the function

script0

@Nonnull
public static <T> Func0<T> script0(@Nonnull
                                             java.lang.String expression,
                                             @Nonnull
                                             javax.script.ScriptEngine engine,
                                             @Nonnull
                                             java.lang.Object... nameThenObject)

Creates a parameterless function which executes the given script as javascript. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the result type

Parameters:

expression - the lambda expression

engine - the scripting engine to use

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function

script1

@Nonnull
public static <T,U> Func1<U,T> script1(@Nonnull
                                                 java.lang.String expression,
                                                 @Nonnull
                                                 javax.script.ScriptEngine engine,
                                                 @Nonnull
                                                 java.util.Map<java.lang.String,java.lang.Object> bindings)

Creates a single parameter function which invokes the script engine with a given expression and returns its result.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the result type of the function

U - the parameter type

Parameters:

expression - the lambda expression

engine - the engine to run the expression

bindings - the external resources the script might need

Returns:

the function

script1

@Nonnull
public static <T,U> Func1<T,U> script1(@Nonnull
                                                 java.lang.String expression,
                                                 @Nonnull
                                                 javax.script.ScriptEngine engine,
                                                 @Nonnull
                                                 java.lang.Object... nameThenObject)

Creates a single parameter function which executes the given script as javascript. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the result type

U - the parameter type of the function

Parameters:

expression - the lambda expression

engine - the script engine to use

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function

script2

@Nonnull
public static <T,U,V> Func2<U,V,T> script2(@Nonnull
                                                     java.lang.String expression,
                                                     @Nonnull
                                                     javax.script.ScriptEngine engine,
                                                     @Nonnull
                                                     java.util.Map<java.lang.String,java.lang.Object> bindings)

Creates a two parameter function which invokes the script engine with a given expression and returns its result.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName1, paramName2 => expression1; expression; return result;

Type Parameters:

T - the result type of the function

U - the first parameter type

V - the second parameter type

Parameters:

expression - the lambda expression

engine - the engine to run the expression

bindings - the external resources the script might need

Returns:

the function

script2

@Nonnull
public static <T,U,V> Func2<T,U,V> script2(@Nonnull
                                                     java.lang.String expression,
                                                     @Nonnull
                                                     javax.script.ScriptEngine engine,
                                                     @Nonnull
                                                     java.lang.Object... nameThenObject)

Creates a two parameter function which executes the given script as javascript. In addition, you may specify extra bindings in the varargs parameters as [String(name), Object(value)] type, e.g., "ref1", 1, "ref2", 2.0.

The syntax of the expression follows the generic lambda format used throughout this utility class:

paramName => expression1; expression; return result;

Type Parameters:

T - the result type

U - the first parameter type

V - the second parameter type

Parameters:

expression - the lambda expression

engine - the script engine to use

nameThenObject - the String, Object, String, Object, ... sequence of name and value pairs.

Returns:

the function