001: /*
002: * Copyright (c) 2003 The Visigoth Software Society. All rights
003: * reserved.
004: *
005: * Redistribution and use in source and binary forms, with or without
006: * modification, are permitted provided that the following conditions
007: * are met:
008: *
009: * 1. Redistributions of source code must retain the above copyright
010: * notice, this list of conditions and the following disclaimer.
011: *
012: * 2. Redistributions in binary form must reproduce the above copyright
013: * notice, this list of conditions and the following disclaimer in
014: * the documentation and/or other materials provided with the
015: * distribution.
016: *
017: * 3. The end-user documentation included with the redistribution, if
018: * any, must include the following acknowledgement:
019: * "This product includes software developed by the
020: * Visigoth Software Society (http://www.visigoths.org/)."
021: * Alternately, this acknowledgement may appear in the software itself,
022: * if and wherever such third-party acknowledgements normally appear.
023: *
024: * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
025: * project contributors may be used to endorse or promote products derived
026: * from this software without prior written permission. For written
027: * permission, please contact visigoths@visigoths.org.
028: *
029: * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
030: * nor may "FreeMarker" or "Visigoth" appear in their names
031: * without prior written permission of the Visigoth Software Society.
032: *
033: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
034: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
035: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
036: * DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
037: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
038: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
039: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
040: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
041: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
042: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
043: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
044: * SUCH DAMAGE.
045: * ====================================================================
046: *
047: * This software consists of voluntary contributions made by many
048: * individuals on behalf of the Visigoth Software Society. For more
049: * information on the Visigoth Software Society, please see
050: * http://www.visigoths.org/
051: */
052:
053: package freemarker.core;
054:
055: import freemarker.template.*;
056:
057: /**
058: * A reference to a top-level variable
059: */
060: final class Identifier extends Expression {
061:
062: private final String name;
063:
064: Identifier(String name) {
065: this .name = name;
066: }
067:
068: TemplateModel _getAsTemplateModel(Environment env)
069: throws TemplateException {
070: try {
071: return env.getVariable(name);
072: } catch (NullPointerException e) {
073: if (env == null) {
074: throw new TemplateException(
075: "Variables are not available "
076: + "(certainly you are in a parse-time executed directive). The name of the variable "
077: + "you tried to read: " + name, null);
078: } else {
079: throw e;
080: }
081: }
082: }
083:
084: public String toString() {
085: return name;
086: }
087:
088: public String getCanonicalForm() {
089: return name;
090: }
091:
092: boolean isLiteral() {
093: return false;
094: }
095:
096: Expression _deepClone(String name, Expression subst) {
097: if (this .name.equals(name)) {
098: return subst.deepClone(null, null);
099: }
100: return new Identifier(this.name);
101: }
102:
103: }
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