PropertyParser.java
- /*
- * Copyright 2009-2024 the original author or authors.
- *
- * 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
- *
- * https://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 org.apache.ibatis.parsing;
- import java.util.Properties;
- /**
- * @author Clinton Begin
- * @author Kazuki Shimizu
- */
- public class PropertyParser {
- private static final String KEY_PREFIX = "org.apache.ibatis.parsing.PropertyParser.";
- /**
- * The special property key that indicate whether enable a default value on placeholder.
- * <p>
- * The default value is {@code false} (indicate disable a default value on placeholder) If you specify the
- * {@code true}, you can specify key and default value on placeholder (e.g. {@code ${db.username:postgres}}).
- *
- * @since 3.4.2
- */
- public static final String KEY_ENABLE_DEFAULT_VALUE = KEY_PREFIX + "enable-default-value";
- /**
- * The special property key that specify a separator for key and default value on placeholder.
- * <p>
- * The default separator is {@code ":"}.
- *
- * @since 3.4.2
- */
- public static final String KEY_DEFAULT_VALUE_SEPARATOR = KEY_PREFIX + "default-value-separator";
- private static final String ENABLE_DEFAULT_VALUE = "false";
- private static final String DEFAULT_VALUE_SEPARATOR = ":";
- private PropertyParser() {
- // Prevent Instantiation
- }
- public static String parse(String string, Properties variables) {
- VariableTokenHandler handler = new VariableTokenHandler(variables);
- GenericTokenParser parser = new GenericTokenParser("${", "}", handler);
- return parser.parse(string);
- }
- private static class VariableTokenHandler implements TokenHandler {
- private final Properties variables;
- private final boolean enableDefaultValue;
- private final String defaultValueSeparator;
- private VariableTokenHandler(Properties variables) {
- this.variables = variables;
- this.enableDefaultValue = Boolean.parseBoolean(getPropertyValue(KEY_ENABLE_DEFAULT_VALUE, ENABLE_DEFAULT_VALUE));
- this.defaultValueSeparator = getPropertyValue(KEY_DEFAULT_VALUE_SEPARATOR, DEFAULT_VALUE_SEPARATOR);
- }
- private String getPropertyValue(String key, String defaultValue) {
- return variables == null ? defaultValue : variables.getProperty(key, defaultValue);
- }
- @Override
- public String handleToken(String content) {
- if (variables != null) {
- String key = content;
- if (enableDefaultValue) {
- final int separatorIndex = content.indexOf(defaultValueSeparator);
- String defaultValue = null;
- if (separatorIndex >= 0) {
- key = content.substring(0, separatorIndex);
- defaultValue = content.substring(separatorIndex + defaultValueSeparator.length());
- }
- if (defaultValue != null) {
- return variables.getProperty(key, defaultValue);
- }
- }
- if (variables.containsKey(key)) {
- return variables.getProperty(key);
- }
- }
- return "${" + content + "}";
- }
- }
- }