diff --git a/src/java/org/apache/commons/lang/text/MappedMessageFormat.java b/src/java/org/apache/commons/lang/text/MappedMessageFormat.java new file mode 100644 index 000000000..8133d1196 --- /dev/null +++ b/src/java/org/apache/commons/lang/text/MappedMessageFormat.java @@ -0,0 +1,133 @@ +/* + * Copyright 2002-2004 The Apache Software Foundation. + * + * 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 org.apache.commons.lang.text; + +import java.util.Map; +import java.util.ArrayList; + +/** + * Provides the ability to substitute values from one or more maps into + * designated places within a string. + *

+ * For example: + *

+ *   "User ${id} has uid ${uid} and path of env{path}"
+ * 
+ * can be expanded using values from a map associated with "$" and a different + * map associated with "env". + *

+ * This class is similar to the java.text.MessageFormat class, but allows + * data to be retrieved from one or maps instead of from a single list. + * Unlike the MessageFormat class, however, it simply uses the result of + * applying toString() to the referenced values in the map(s) and does not + * support any "format" operations applied to the objects before substitution + * into the target string. + * + * @since 2.1 + */ + +public class MappedMessageFormat { + private int nEntries = 0; + private ArrayList markers = new ArrayList(2); + private ArrayList sources = new ArrayList(2); + + public MappedMessageFormat() { + } + + /** + * Defines a source of data that can later be substituted into + * strings passed to the "format" methods. + */ + public void addSource(String marker, Map source) { + ++nEntries; + markers.add(marker); + sources.add(source); + } + + /** + * Expands any variable declarations using any of the known + * variable marker strings. + * + * @throws IllegalArgumentException if the input param references + * a variable which is not known to the specified source. + */ + public String format(String param) { + for(int i=0; i + * Commonly, the variable marker is "$", in which case variables + * are indicated by ${key} in the string. + *

+ * Returns the string after performing all substitutions. + *

+ * If no substitutions were made, the input string object is + * returned (not a copy). + * + * @throws IllegalArgumentException if the input param references + * a variable which is not known to the specified source. + */ + public static String format(String str, String marker, Map source) { + String startMark = marker + "{"; + int markLen = startMark.length(); + + int index = 0; + for(;;) + { + index = str.indexOf(startMark, index); + if (index == -1) + { + return str; + } + + int startIndex = index + markLen; + if (startIndex > str.length()) + { + throw new IllegalArgumentException( + "var expression starts at end of string"); + } + + int endIndex = str.indexOf("}", index + markLen); + if (endIndex == -1) + { + throw new IllegalArgumentException( + "var expression starts but does not end"); + } + + String key = str.substring(index+markLen, endIndex); + Object value = source.get(key); + if (value == null) { + throw new IllegalArgumentException( + "parameter [" + key + "] is not defined."); + } + String varValue = value.toString(); + + str = str.substring(0, index) + varValue + str.substring(endIndex+1); + index += varValue.length(); + } + } + +} +