/*
* Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
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package javax.script;
import java.util.*;
import java.io.*;
/**
* Simple implementation of ScriptContext.
*
* @author Mike Grogan
* @since 1.6
*/
public class
SimpleScriptContext implements
ScriptContext {
/**
* This is the writer to be used to output from scripts.
* By default, a <code>PrintWriter</code> based on <code>System.out</code>
* is used. Accessor methods getWriter, setWriter are used to manage
* this field.
* @see java.lang.System#out
* @see java.io.PrintWriter
*/
protected
Writer writer;
/**
* This is the writer to be used to output errors from scripts.
* By default, a <code>PrintWriter</code> based on <code>System.err</code> is
* used. Accessor methods getErrorWriter, setErrorWriter are used to manage
* this field.
* @see java.lang.System#err
* @see java.io.PrintWriter
*/
protected
Writer errorWriter;
/**
* This is the reader to be used for input from scripts.
* By default, a <code>InputStreamReader</code> based on <code>System.in</code>
* is used and default charset is used by this reader. Accessor methods
* getReader, setReader are used to manage this field.
* @see java.lang.System#in
* @see java.io.InputStreamReader
*/
protected
Reader reader;
/**
* This is the engine scope bindings.
* By default, a <code>SimpleBindings</code> is used. Accessor
* methods setBindings, getBindings are used to manage this field.
* @see SimpleBindings
*/
protected
Bindings engineScope;
/**
* This is the global scope bindings.
* By default, a null value (which means no global scope) is used. Accessor
* methods setBindings, getBindings are used to manage this field.
*/
protected
Bindings globalScope;
/**
* Create a {@code SimpleScriptContext}.
*/
public
SimpleScriptContext() {
engineScope = new
SimpleBindings();
globalScope = null;
reader = new
InputStreamReader(
System.
in);
writer = new
PrintWriter(
System.
out , true);
errorWriter = new
PrintWriter(
System.
err, true);
}
/**
* Sets a <code>Bindings</code> of attributes for the given scope. If the value
* of scope is <code>ENGINE_SCOPE</code> the given <code>Bindings</code> replaces the
* <code>engineScope</code> field. If the value
* of scope is <code>GLOBAL_SCOPE</code> the given <code>Bindings</code> replaces the
* <code>globalScope</code> field.
*
* @param bindings The <code>Bindings</code> of attributes to set.
* @param scope The value of the scope in which the attributes are set.
*
* @throws IllegalArgumentException if scope is invalid.
* @throws NullPointerException if the value of scope is <code>ENGINE_SCOPE</code> and
* the specified <code>Bindings</code> is null.
*/
public void
setBindings(
Bindings bindings, int
scope) {
switch (
scope) {
case
ENGINE_SCOPE:
if (
bindings == null) {
throw new
NullPointerException("Engine scope cannot be null.");
}
engineScope =
bindings;
break;
case
GLOBAL_SCOPE:
globalScope =
bindings;
break;
default:
throw new
IllegalArgumentException("Invalid scope value.");
}
}
/**
* Retrieves the value of the attribute with the given name in
* the scope occurring earliest in the search order. The order
* is determined by the numeric value of the scope parameter (lowest
* scope values first.)
*
* @param name The name of the the attribute to retrieve.
* @return The value of the attribute in the lowest scope for
* which an attribute with the given name is defined. Returns
* null if no attribute with the name exists in any scope.
* @throws NullPointerException if the name is null.
* @throws IllegalArgumentException if the name is empty.
*/
public
Object getAttribute(
String name) {
checkName(
name);
if (
engineScope.
containsKey(
name)) {
return
getAttribute(
name,
ENGINE_SCOPE);
} else if (
globalScope != null &&
globalScope.
containsKey(
name)) {
return
getAttribute(
name,
GLOBAL_SCOPE);
}
return null;
}
/**
* Gets the value of an attribute in a given scope.
*
* @param name The name of the attribute to retrieve.
* @param scope The scope in which to retrieve the attribute.
* @return The value of the attribute. Returns <code>null</code> is the name
* does not exist in the given scope.
*
* @throws IllegalArgumentException
* if the name is empty or if the value of scope is invalid.
* @throws NullPointerException if the name is null.
*/
public
Object getAttribute(
String name, int
scope) {
checkName(
name);
switch (
scope) {
case
ENGINE_SCOPE:
return
engineScope.
get(
name);
case
GLOBAL_SCOPE:
if (
globalScope != null) {
return
globalScope.
get(
name);
}
return null;
default:
throw new
IllegalArgumentException("Illegal scope value.");
}
}
/**
* Remove an attribute in a given scope.
*
* @param name The name of the attribute to remove
* @param scope The scope in which to remove the attribute
*
* @return The removed value.
* @throws IllegalArgumentException
* if the name is empty or if the scope is invalid.
* @throws NullPointerException if the name is null.
*/
public
Object removeAttribute(
String name, int
scope) {
checkName(
name);
switch (
scope) {
case
ENGINE_SCOPE:
if (
getBindings(
ENGINE_SCOPE) != null) {
return
getBindings(
ENGINE_SCOPE).
remove(
name);
}
return null;
case
GLOBAL_SCOPE:
if (
getBindings(
GLOBAL_SCOPE) != null) {
return
getBindings(
GLOBAL_SCOPE).
remove(
name);
}
return null;
default:
throw new
IllegalArgumentException("Illegal scope value.");
}
}
/**
* Sets the value of an attribute in a given scope.
*
* @param name The name of the attribute to set
* @param value The value of the attribute
* @param scope The scope in which to set the attribute
*
* @throws IllegalArgumentException
* if the name is empty or if the scope is invalid.
* @throws NullPointerException if the name is null.
*/
public void
setAttribute(
String name,
Object value, int
scope) {
checkName(
name);
switch (
scope) {
case
ENGINE_SCOPE:
engineScope.
put(
name,
value);
return;
case
GLOBAL_SCOPE:
if (
globalScope != null) {
globalScope.
put(
name,
value);
}
return;
default:
throw new
IllegalArgumentException("Illegal scope value.");
}
}
/** {@inheritDoc} */
public
Writer getWriter() {
return
writer;
}
/** {@inheritDoc} */
public
Reader getReader() {
return
reader;
}
/** {@inheritDoc} */
public void
setReader(
Reader reader) {
this.
reader =
reader;
}
/** {@inheritDoc} */
public void
setWriter(
Writer writer) {
this.
writer =
writer;
}
/** {@inheritDoc} */
public
Writer getErrorWriter() {
return
errorWriter;
}
/** {@inheritDoc} */
public void
setErrorWriter(
Writer writer) {
this.
errorWriter =
writer;
}
/**
* Get the lowest scope in which an attribute is defined.
* @param name Name of the attribute
* .
* @return The lowest scope. Returns -1 if no attribute with the given
* name is defined in any scope.
* @throws NullPointerException if name is null.
* @throws IllegalArgumentException if name is empty.
*/
public int
getAttributesScope(
String name) {
checkName(
name);
if (
engineScope.
containsKey(
name)) {
return
ENGINE_SCOPE;
} else if (
globalScope != null &&
globalScope.
containsKey(
name)) {
return
GLOBAL_SCOPE;
} else {
return -1;
}
}
/**
* Returns the value of the <code>engineScope</code> field if specified scope is
* <code>ENGINE_SCOPE</code>. Returns the value of the <code>globalScope</code> field if the specified scope is
* <code>GLOBAL_SCOPE</code>.
*
* @param scope The specified scope
* @return The value of either the <code>engineScope</code> or <code>globalScope</code> field.
* @throws IllegalArgumentException if the value of scope is invalid.
*/
public
Bindings getBindings(int
scope) {
if (
scope ==
ENGINE_SCOPE) {
return
engineScope;
} else if (
scope ==
GLOBAL_SCOPE) {
return
globalScope;
} else {
throw new
IllegalArgumentException("Illegal scope value.");
}
}
/** {@inheritDoc} */
public
List<
Integer>
getScopes() {
return
scopes;
}
private void
checkName(
String name) {
Objects.
requireNonNull(
name);
if (
name.
isEmpty()) {
throw new
IllegalArgumentException("name cannot be empty");
}
}
private static
List<
Integer>
scopes;
static {
scopes = new
ArrayList<
Integer>(2);
scopes.
add(
ENGINE_SCOPE);
scopes.
add(
GLOBAL_SCOPE);
scopes =
Collections.
unmodifiableList(
scopes);
}
}