com.mitchellbosecke.pebble.template

Class ScopeChain

java.lang.Object

com.mitchellbosecke.pebble.template.ScopeChain

public class ScopeChain
extends Object

A stack data structure used to represent the scope of variables that are currently accessible. Pushing a new scope will allow the template to add variables with names of pre-existing variables without overriding the originals; to access the original variables you would pop the scope again.

Constructor Summary

Constructors

Constructor and Description
ScopeChain() Constructs an empty scope chain without any known scopes.
ScopeChain(Map<String,Object> map) Constructs a new scope chain with one known scope.

Method Summary

Modifier and Type	Method and Description
boolean	containsKey(String key) This method checks if the given key does exists within the scope chain.
boolean	currentScopeContainsVariable(String variableName) Checks if the current scope contains a variable without then looking up the scope chain.
ScopeChain	deepCopy() Creates a deep copy of the ScopeChain.
Object	get(String key) Retrieves a variable from the scope chain, starting at the current scope and working it's way up all visible scopes.
void	popScope() Pops the most recent scope from the scope chain.
void	pushLocalScope() Adds a new local scope to the scope chain
void	pushScope() Adds an empty non-local scope to the scope chain
void	pushScope(Map<String,Object> map) Adds a new non-local scope to the scope chain
void	put(String key, Object value) Adds a variable to the current scope.
void	set(String key, Object value) Sets the value of a variable in the first scope in the chain that already contains the variable; adds a variable to the current scope if an existing variable is not found.

Methods inherited from class java.lang.Object

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

Constructor Detail

ScopeChain

public ScopeChain()

Constructs an empty scope chain without any known scopes.

ScopeChain

public ScopeChain(Map<String,Object> map)

Constructs a new scope chain with one known scope.

Parameters:

map - The map of variables used to initialize a scope.

Method Detail

deepCopy

public ScopeChain deepCopy()

Creates a deep copy of the ScopeChain. This is used for the parallel tag because every new thread should have a "snapshot" of the scopes, i.e. if one thread adds a new object to a scope, it should not be available to the other threads.

This will construct a new scope chain and new scopes but it will continue to have references to the original user-provided variables. This is why it is important for the user to only provide thread-safe variables when using the "parallel" tag.

Returns:

A copy of the scope chain

pushScope

public void pushScope()

Adds an empty non-local scope to the scope chain

pushScope

public void pushScope(Map<String,Object> map)

Adds a new non-local scope to the scope chain

Parameters:

map - The known variables of this scope.

pushLocalScope

public void pushLocalScope()

Adds a new local scope to the scope chain

popScope

public void popScope()

Pops the most recent scope from the scope chain.

put

public void put(String key,
                Object value)

Adds a variable to the current scope.

Parameters:

key - The name of the variable

value - The value of the variable

get

public Object get(String key)

Retrieves a variable from the scope chain, starting at the current scope and working it's way up all visible scopes.

Parameters:

key - The name of the variable

Returns:

The value of the variable

containsKey

public boolean containsKey(String key)

This method checks if the given key does exists within the scope chain.

Parameters:

key - the for which the the check should be executed for.

Returns:

true when the key does exists or false when the given key does not exists.

currentScopeContainsVariable

public boolean currentScopeContainsVariable(String variableName)

Checks if the current scope contains a variable without then looking up the scope chain.

Parameters:

variableName - The name of the variable

Returns:

Whether or not the variable exists in the current scope

set

public void set(String key,
                Object value)

Sets the value of a variable in the first scope in the chain that already contains the variable; adds a variable to the current scope if an existing variable is not found.

Parameters:

key - The name of the variable

value - The value of the variable