/* |
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* Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package javax.script; |
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import java.io.Reader; |
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import java.util.Map; |
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import java.util.Iterator; |
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/** |
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* Provides a standard implementation for several of the variants of the <code>eval</code> |
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* method. |
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* <br><br> |
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* <code><b>eval(Reader)</b></code><p><code><b>eval(String)</b></code><p> |
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* <code><b>eval(String, Bindings)</b></code><p><code><b>eval(Reader, Bindings)</b></code> |
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* <br><br> are implemented using the abstract methods |
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* <br><br> |
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* <code><b>eval(Reader,ScriptContext)</b></code> or |
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* <code><b>eval(String, ScriptContext)</b></code> |
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* <br><br> |
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* with a <code>SimpleScriptContext</code>. |
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* <br><br> |
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* A <code>SimpleScriptContext</code> is used as the default <code>ScriptContext</code> |
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* of the <code>AbstractScriptEngine</code>.. |
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* |
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* @author Mike Grogan |
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* @since 1.6 |
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*/ |
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public abstract class AbstractScriptEngine implements ScriptEngine { |
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/** |
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* The default <code>ScriptContext</code> of this <code>AbstractScriptEngine</code>. |
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*/ |
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protected ScriptContext context; |
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/** |
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* Creates a new instance of AbstractScriptEngine using a <code>SimpleScriptContext</code> |
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* as its default <code>ScriptContext</code>. |
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*/ |
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public AbstractScriptEngine() { |
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context = new SimpleScriptContext(); |
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} |
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/** |
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* Creates a new instance using the specified <code>Bindings</code> as the |
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* <code>ENGINE_SCOPE</code> <code>Bindings</code> in the protected <code>context</code> field. |
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* |
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* @param n The specified <code>Bindings</code>. |
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* @throws NullPointerException if n is null. |
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*/ |
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public AbstractScriptEngine(Bindings n) { |
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this(); |
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if (n == null) { |
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throw new NullPointerException("n is null"); |
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} |
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context.setBindings(n, ScriptContext.ENGINE_SCOPE); |
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} |
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/** |
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* Sets the value of the protected <code>context</code> field to the specified |
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* <code>ScriptContext</code>. |
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* |
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* @param ctxt The specified <code>ScriptContext</code>. |
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* @throws NullPointerException if ctxt is null. |
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*/ |
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public void setContext(ScriptContext ctxt) { |
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if (ctxt == null) { |
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throw new NullPointerException("null context"); |
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} |
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context = ctxt; |
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} |
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/** |
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* Returns the value of the protected <code>context</code> field. |
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* |
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* @return The value of the protected <code>context</code> field. |
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*/ |
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public ScriptContext getContext() { |
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return context; |
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} |
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/** |
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* Returns the <code>Bindings</code> with the specified scope value in |
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* the protected <code>context</code> field. |
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* |
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* @param scope The specified scope |
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* |
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* @return The corresponding <code>Bindings</code>. |
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* |
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* @throws IllegalArgumentException if the value of scope is |
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* invalid for the type the protected <code>context</code> field. |
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*/ |
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public Bindings getBindings(int scope) { |
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if (scope == ScriptContext.GLOBAL_SCOPE) { |
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return context.getBindings(ScriptContext.GLOBAL_SCOPE); |
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} else if (scope == ScriptContext.ENGINE_SCOPE) { |
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return context.getBindings(ScriptContext.ENGINE_SCOPE); |
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} else { |
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throw new IllegalArgumentException("Invalid scope value."); |
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} |
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} |
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/** |
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* Sets the <code>Bindings</code> with the corresponding scope value in the |
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* <code>context</code> field. |
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* |
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* @param bindings The specified <code>Bindings</code>. |
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* @param scope The specified scope. |
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* |
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* @throws IllegalArgumentException if the value of scope is |
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* invalid for the type the <code>context</code> field. |
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* @throws NullPointerException if the bindings is null and the scope is |
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* <code>ScriptContext.ENGINE_SCOPE</code> |
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*/ |
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public void setBindings(Bindings bindings, int scope) { |
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if (scope == ScriptContext.GLOBAL_SCOPE) { |
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context.setBindings(bindings, ScriptContext.GLOBAL_SCOPE);; |
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} else if (scope == ScriptContext.ENGINE_SCOPE) { |
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context.setBindings(bindings, ScriptContext.ENGINE_SCOPE);; |
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} else { |
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throw new IllegalArgumentException("Invalid scope value."); |
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} |
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} |
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/** |
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* Sets the specified value with the specified key in the <code>ENGINE_SCOPE</code> |
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* <code>Bindings</code> of the protected <code>context</code> field. |
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* |
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* @param key The specified key. |
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* @param value The specified value. |
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* |
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* @throws NullPointerException if key is null. |
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* @throws IllegalArgumentException if key is empty. |
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*/ |
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public void put(String key, Object value) { |
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Bindings nn = getBindings(ScriptContext.ENGINE_SCOPE); |
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if (nn != null) { |
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nn.put(key, value); |
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} |
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} |
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/** |
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* Gets the value for the specified key in the <code>ENGINE_SCOPE</code> of the |
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* protected <code>context</code> field. |
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* |
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* @return The value for the specified key. |
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* |
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* @throws NullPointerException if key is null. |
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* @throws IllegalArgumentException if key is empty. |
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*/ |
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public Object get(String key) { |
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Bindings nn = getBindings(ScriptContext.ENGINE_SCOPE); |
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if (nn != null) { |
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return nn.get(key); |
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} |
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return null; |
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} |
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/** |
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* <code>eval(Reader, Bindings)</code> calls the abstract |
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* <code>eval(Reader, ScriptContext)</code> method, passing it a <code>ScriptContext</code> |
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* whose Reader, Writers and Bindings for scopes other that <code>ENGINE_SCOPE</code> |
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* are identical to those members of the protected <code>context</code> field. The specified |
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* <code>Bindings</code> is used instead of the <code>ENGINE_SCOPE</code> |
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* |
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* <code>Bindings</code> of the <code>context</code> field. |
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* |
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* @param reader A <code>Reader</code> containing the source of the script. |
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* @param bindings A <code>Bindings</code> to use for the <code>ENGINE_SCOPE</code> |
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* while the script executes. |
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* |
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* @return The return value from <code>eval(Reader, ScriptContext)</code> |
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* @throws ScriptException if an error occurs in script. |
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* @throws NullPointerException if any of the parameters is null. |
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*/ |
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public Object eval(Reader reader, Bindings bindings ) throws ScriptException { |
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ScriptContext ctxt = getScriptContext(bindings); |
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return eval(reader, ctxt); |
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} |
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/** |
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* Same as <code>eval(Reader, Bindings)</code> except that the abstract |
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* <code>eval(String, ScriptContext)</code> is used. |
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* |
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* @param script A <code>String</code> containing the source of the script. |
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* |
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* @param bindings A <code>Bindings</code> to use as the <code>ENGINE_SCOPE</code> |
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* while the script executes. |
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* |
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* @return The return value from <code>eval(String, ScriptContext)</code> |
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* @throws ScriptException if an error occurs in script. |
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* @throws NullPointerException if any of the parameters is null. |
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*/ |
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public Object eval(String script, Bindings bindings) throws ScriptException { |
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ScriptContext ctxt = getScriptContext(bindings); |
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return eval(script , ctxt); |
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} |
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/** |
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* <code>eval(Reader)</code> calls the abstract |
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* <code>eval(Reader, ScriptContext)</code> passing the value of the <code>context</code> |
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* field. |
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* |
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* @param reader A <code>Reader</code> containing the source of the script. |
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* @return The return value from <code>eval(Reader, ScriptContext)</code> |
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* @throws ScriptException if an error occurs in script. |
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* @throws NullPointerException if any of the parameters is null. |
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*/ |
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public Object eval(Reader reader) throws ScriptException { |
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return eval(reader, context); |
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} |
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/** |
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* Same as <code>eval(Reader)</code> except that the abstract |
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* <code>eval(String, ScriptContext)</code> is used. |
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* |
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* @param script A <code>String</code> containing the source of the script. |
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* @return The return value from <code>eval(String, ScriptContext)</code> |
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* @throws ScriptException if an error occurs in script. |
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* @throws NullPointerException if any of the parameters is null. |
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*/ |
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public Object eval(String script) throws ScriptException { |
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return eval(script, context); |
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} |
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/** |
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* Returns a <code>SimpleScriptContext</code>. The <code>SimpleScriptContext</code>: |
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*<br><br> |
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* <ul> |
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* <li>Uses the specified <code>Bindings</code> for its <code>ENGINE_SCOPE</code> |
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* </li> |
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* <li>Uses the <code>Bindings</code> returned by the abstract <code>getGlobalScope</code> |
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* method as its <code>GLOBAL_SCOPE</code> |
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* </li> |
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* <li>Uses the Reader and Writer in the default <code>ScriptContext</code> of this |
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* <code>ScriptEngine</code> |
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* </li> |
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* </ul> |
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* <br><br> |
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* A <code>SimpleScriptContext</code> returned by this method is used to implement eval methods |
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* using the abstract <code>eval(Reader,Bindings)</code> and <code>eval(String,Bindings)</code> |
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* versions. |
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* |
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* @param nn Bindings to use for the <code>ENGINE_SCOPE</code> |
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* @return The <code>SimpleScriptContext</code> |
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*/ |
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protected ScriptContext getScriptContext(Bindings nn) { |
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SimpleScriptContext ctxt = new SimpleScriptContext(); |
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Bindings gs = getBindings(ScriptContext.GLOBAL_SCOPE); |
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if (gs != null) { |
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ctxt.setBindings(gs, ScriptContext.GLOBAL_SCOPE); |
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} |
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if (nn != null) { |
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ctxt.setBindings(nn, |
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ScriptContext.ENGINE_SCOPE); |
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} else { |
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throw new NullPointerException("Engine scope Bindings may not be null."); |
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} |
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ctxt.setReader(context.getReader()); |
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ctxt.setWriter(context.getWriter()); |
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ctxt.setErrorWriter(context.getErrorWriter()); |
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return ctxt; |
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} |
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} |