svn commit: r280214 - in /incubator/roller/trunk: src/org/roller/util/PropertyExpander.java tests/org/roller/util/PropertyExpanderTest.java

[ga...@apache.org]

Author: gangolli
Date: Sun Sep 11 16:46:40 2005
New Revision: 280214

URL: http://svn.apache.org/viewcvs?rev=280214&view=rev
Log:
Property expander utility and unit test.  Will be used for system property expansion of config property values.  Part 1 of checkin for ROL-613.

Added:
    incubator/roller/trunk/src/org/roller/util/PropertyExpander.java
    incubator/roller/trunk/tests/org/roller/util/PropertyExpanderTest.java

Added: incubator/roller/trunk/src/org/roller/util/PropertyExpander.java
URL: http://svn.apache.org/viewcvs/incubator/roller/trunk/src/org/roller/util/PropertyExpander.java?rev=280214&view=auto
==============================================================================
--- incubator/roller/trunk/src/org/roller/util/PropertyExpander.java (added)
+++ incubator/roller/trunk/src/org/roller/util/PropertyExpander.java Sun Sep 11 16:46:40 2005
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2005 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.roller.util;
+
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Property expansion utility.  This utility provides static methods to expand properties appearing in strings.
+ *
+ * @author <a href="mailto:anil@busybuddha.org">Anil Gangolli</a> (Portions based on code from David Graff submitted for
+ *         ROL-613)
+ * @since Roller 1.3
+ */
+public class PropertyExpander
+{
+    private PropertyExpander()
+    {
+    }
+
+    // The pattern for a system property.  Matches ${property.name}, with the interior matched reluctantly.
+    private static final Pattern EXPANSION_PATTERN =
+        Pattern.compile("(\\$\\{([^}]+?)\\})", java.util.regex.Pattern.MULTILINE);
+
+    /**
+     * Expand property expressions in the input.  Expands property expressions of the form <code>${propertyname}</code>
+     * in the input, replacing each such expression with the value associated to the respective key
+     * <code>propertyname</code> in the supplied map.  If for a given expression, the property is undefined (has null
+     * value) in the map supplied, that expression is left unexpanded in the resulting string.
+     * <p/>
+     * Note that expansion is not recursive.  If the value of one property contains another expression, the expression
+     * appearing in the value will not be expanded further.
+     *
+     * @param input the input string.  This may be null, in which case null is returned.
+     * @param props the map of property values to use for expansion.  This map should have <code>String</code> keys and
+     *              <code>String</code> values.  Any object of class {@link java.util.Properties} works here, as will
+     *              other implementations of such maps.
+     * @return the result of replacing property expressions with the values of the corresponding properties from the
+     *         supplied property map, null if the input string is null.
+     */
+    public static String expandProperties(String input, Map props)
+    {
+        if (input == null) return null;
+
+        Matcher matcher = EXPANSION_PATTERN.matcher(input);
+
+        StringBuffer expanded = new StringBuffer(input.length());
+        while (matcher.find())
+        {
+            String propName = matcher.group(2);
+            String value = (String) props.get(propName);
+            // if no value is found, use a value equal to the original expression
+            if (value == null) value = matcher.group(0);
+            // Fake a literal replacement since Matcher.quoteReplacement() is not present in 1.4.
+            matcher.appendReplacement(expanded, "");
+            expanded.append(value);
+        }
+        matcher.appendTail(expanded);
+
+        return expanded.toString();
+    }
+
+    /**
+     * Expand system properties in the input string.  This is equivalent to calling <code>expandProperties(input,
+     * System.getProperties())</code>.
+     *
+     * @param input
+     * @return the result of replacing property expressions with the values of the corresponding system properties.
+     * @see System#getProperties()
+     */
+    public static String expandSystemProperties(String input)
+    {
+        return expandProperties(input, System.getProperties());
+    }
+}

Added: incubator/roller/trunk/tests/org/roller/util/PropertyExpanderTest.java
URL: http://svn.apache.org/viewcvs/incubator/roller/trunk/tests/org/roller/util/PropertyExpanderTest.java?rev=280214&view=auto
==============================================================================
--- incubator/roller/trunk/tests/org/roller/util/PropertyExpanderTest.java (added)
+++ incubator/roller/trunk/tests/org/roller/util/PropertyExpanderTest.java Sun Sep 11 16:46:40 2005
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2005
+ * Anil R. Gangolli. All rights reserved.
+ *
+ * Distributed with the Roller Weblogger Project under the terms of the Roller Software
+ * License
+ */
+
+package org.roller.util;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import junit.framework.TestCase;
+
+/**
+ * Unit test for org.roller.util.PropertyExpander.
+ */
+public class PropertyExpanderTest extends TestCase
+{
+    private static final Map props = new HashMap();
+
+    static
+    {
+        props.put("defined.property.one", "value one");
+        props.put("defined.property.two", "value two");
+        props.put("defined.property.with.dollar.sign.in.value", "$2");
+    }
+
+    public void testExpansion() throws Exception
+    {
+        String expanded =
+            PropertyExpander.expandProperties("String with ${defined.property.one} and ${defined.property.two} and ${defined.property.with.dollar.sign.in.value} and ${undefined.property} and some stuff.", props);
+
+        assertEquals("Expanded string doesn't match expected",
+            "String with value one and value two and $2 and ${undefined.property} and some stuff.",
+            expanded);
+    }
+
+    public void testSystemProperty() throws Exception
+    {
+        String expanded =
+            PropertyExpander.expandSystemProperties("${java.home}");
+        assertEquals("Expanded string doesn't match expected",
+            System.getProperty("java.home"),
+            expanded);
+    }
+
+}