| /* |
| * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Sun designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Sun in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| */ |
| |
| 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; |
| |
| |
| 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) { |
| 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) { |
| |
| 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) { |
| |
| 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) { |
| |
| 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) { |
| 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 static List<Integer> scopes; |
| static { |
| scopes = new ArrayList<Integer>(2); |
| scopes.add(ENGINE_SCOPE); |
| scopes.add(GLOBAL_SCOPE); |
| scopes = Collections.unmodifiableList(scopes); |
| } |
| } |