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Posted to scm@geronimo.apache.org by jd...@apache.org on 2003/08/24 22:13:22 UTC
cvs commit: incubator-geronimo/modules/common/src/java/org/apache/geronimo/common StringValueParser.java
jdillon 2003/08/24 13:13:22
Added: modules/common/src/java/org/apache/geronimo/common
StringValueParser.java
Log:
o forgot this one, moved from twiddle to common
Revision Changes Path
1.1 incubator-geronimo/modules/common/src/java/org/apache/geronimo/common/StringValueParser.java
Index: StringValueParser.java
===================================================================
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" and
* "Apache Geronimo" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* "Apache Geronimo", nor may "Apache" appear in their name, without
* prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* ====================================================================
*/
package org.apache.geronimo.common;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.jexl.JexlHelper;
import org.apache.commons.jexl.JexlContext;
import org.apache.commons.jexl.Expression;
import org.apache.commons.jexl.ExpressionFactory;
import org.apache.commons.jexl.resolver.FlatResolver;
/**
* Handles pasring expressions from a string.
*
* @version <code>$Revision: 1.1 $ $Date: 2003/08/24 20:13:22 $</code>
*/
public class StringValueParser
{
private static final Log log = LogFactory.getLog(StringValueParser.class);
protected JexlContext context;
public StringValueParser(final Map vars)
{
if (vars == null) {
throw new NullArgumentException("vars");
}
context = JexlHelper.createContext();
context.setVars(vars);
if (log.isTraceEnabled()) {
log.trace("Using variables: " + context.getVars());
}
}
public StringValueParser()
{
this(System.getProperties());
}
public Map getVariables()
{
return context.getVars();
}
public Object getVariable(final Object name)
{
if (name == null) {
throw new NullArgumentException("name");
}
return getVariables().get(name);
}
public Object setVariable(final Object name, final Object value)
{
if (name == null) {
throw new NullArgumentException("name");
}
return getVariables().put(name, value);
}
public Object unsetVariable(final Object name)
{
if (name == null) {
throw new NullArgumentException("name");
}
return getVariables().remove(name);
}
public void addVariables(final Map map)
{
if (map == null) {
throw new NullArgumentException("map");
}
getVariables().putAll(map);
}
private FlatResolver resolver = new FlatResolver(true);
protected Expression createExpression(final String expression) throws Exception
{
assert expression != null;
Expression expr = ExpressionFactory.createExpression(expression);
expr.addPreResolver(resolver);
return expr;
}
public Object evaluate(final String expression) throws Exception
{
if (expression == null) {
throw new NullArgumentException("expression");
}
boolean trace = log.isTraceEnabled();
if (trace) {
log.trace("Evaluating expression: " + expression);
}
Expression expr = createExpression(expression);
Object obj = expr.evaluate(context);
if (trace) {
log.trace("Result: " + obj);
}
return obj;
}
public String parse(final String input)
{
if (input == null) {
throw new NullArgumentException("input");
}
boolean trace = log.isTraceEnabled();
if (trace) {
log.trace("Parsing input: " + input);
}
StringBuffer buff = new StringBuffer();
int cur = 0;
int prefixLoc = 0;
int suffixLoc = 0;
while (cur < input.length()) {
prefixLoc = input.indexOf("${", cur);
if (prefixLoc < 0) {
break;
}
suffixLoc = input.indexOf("}", prefixLoc);
if (suffixLoc < 0) {
throw new RuntimeException("Missing '}': " + input);
}
String expr = input.substring(prefixLoc + 2, suffixLoc);
buff.append(input.substring(cur, prefixLoc));
try {
buff.append(evaluate(expr));
}
catch (Exception e) {
throw new RuntimeException("Failed to evaluate: " + expr, e);
}
cur = suffixLoc + 1;
}
buff.append(input.substring(cur));
if (trace) {
log.trace("Parsed result: " + buff);
}
return buff.toString();
}
}