| /* |
| * Copyright (C) 2012 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.android.tools.idea.templates; |
| |
| import com.android.annotations.NonNull; |
| import com.android.annotations.Nullable; |
| import freemarker.cache.TemplateLoader; |
| import freemarker.template.Configuration; |
| import freemarker.template.Template; |
| |
| import java.io.IOException; |
| import java.io.Reader; |
| import java.io.StringReader; |
| import java.io.StringWriter; |
| import java.util.Map; |
| |
| /** |
| * A Freemarker wrapper which can evaluate simple strings. Used to evaluate |
| * parameter constraints during UI wizard value editing. |
| * <p> |
| * Unlike the more general {@link Template} which is used to instantiate |
| * full template files (from resources, merging into existing files etc) this |
| * evaluator supports only simple strings, referencing only values from the |
| * provided map (and builtin functions). |
| */ |
| public class StringEvaluator implements TemplateLoader { |
| private Configuration myFreemarker; |
| private String myCurrentExpression; |
| |
| private static final String BOOLEAN_TEMPLATE = "<#if (%s)>true<#else>false</#if>"; |
| |
| public StringEvaluator() { |
| myFreemarker = new FreemarkerConfiguration(); |
| myFreemarker.setTemplateLoader(this); |
| } |
| |
| /** Evaluates the given expression, with the given set of arguments */ |
| @Nullable |
| public String evaluate(@NonNull String expression, Map<String, Object> inputs) { |
| try { |
| myCurrentExpression = expression; |
| Template inputsTemplate = myFreemarker.getTemplate(expression); |
| StringWriter out = new StringWriter(); |
| Map<String, Object> args = com.android.tools.idea.templates.Template.createParameterMap(inputs); |
| inputsTemplate.process(args, out); |
| out.flush(); |
| return out.toString(); |
| } catch (Exception e) { |
| return null; |
| } |
| } |
| |
| public boolean evaluateBooleanExpression(@NonNull String expression, Map<String, Object> inputs, boolean defaultValue) { |
| try { |
| myCurrentExpression = String.format(BOOLEAN_TEMPLATE, expression); |
| String result = evaluate(myCurrentExpression, inputs); |
| return Boolean.parseBoolean(result); |
| } catch (Exception e) { |
| return defaultValue; |
| } |
| } |
| |
| // ---- Implements TemplateLoader ---- |
| |
| @Override |
| public Object findTemplateSource(String name) throws IOException { |
| return myCurrentExpression; |
| } |
| |
| @Override |
| public long getLastModified(Object templateSource) { |
| return 0; |
| } |
| |
| @Override |
| public Reader getReader(Object templateSource, String encoding) throws IOException { |
| return new StringReader(myCurrentExpression); |
| } |
| |
| @Override |
| public void closeTemplateSource(Object templateSource) throws IOException { |
| } |
| } |