/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 groovy.util;
import groovy.lang.
Binding;
import groovy.lang.
GroovyShell;
import org.codehaus.groovy.control.
CompilationFailedException;
/**
* Allow easy integration from Groovy into Java through convenience methods.
* <p>
* This class is a simple helper on top of GroovyShell. You can use it to evaluate small
* Groovy scripts that don't need large Binding objects. For example, this script
* executes with no errors:
* <pre class="groovyTestCase">
* assert Eval.me(' 2 * 4 + 2') == 10
* assert Eval.x(2, ' x * 4 + 2') == 10
* </pre>
*
* @see GroovyShell
* @author Dierk Koenig
*/
public class
Eval {
/**
* Evaluates the specified String expression and returns the result. For example:
* <pre class="groovyTestCase">
* assert Eval.me(' 2 * 4 + 2') == 10
* </pre>
* @param expression the Groovy expression to evaluate
* @return the result of the expression
* @throws CompilationFailedException if expression is not valid Groovy
*/
public static
Object me(final
String expression) throws
CompilationFailedException {
return
me(null, null,
expression);
}
/**
* Evaluates the specified String expression and makes the parameter available inside
* the script, returning the result. For example, this code binds the 'x' variable:
* <pre class="groovyTestCase">
* assert Eval.me('x', 2, ' x * 4 + 2') == 10
* </pre>
* @param expression the Groovy expression to evaluate
* @return the result of the expression
* @throws CompilationFailedException if expression is not valid Groovy
*/
public static
Object me(final
String symbol, final
Object object, final
String expression) throws
CompilationFailedException {
Binding b = new
Binding();
b.
setVariable(
symbol,
object);
GroovyShell sh = new
GroovyShell(
b);
return
sh.
evaluate(
expression);
}
/**
* Evaluates the specified String expression and makes the parameter available inside
* the script bound to a variable named 'x', returning the result. For example, this
* code executes without failure:
* <pre class="groovyTestCase">
* assert Eval.x(2, ' x * 4 + 2') == 10
* </pre>
* @param expression the Groovy expression to evaluate
* @return the result of the expression
* @throws CompilationFailedException if expression is not valid Groovy
*/
public static
Object x(final
Object x, final
String expression) throws
CompilationFailedException {
return
me("x",
x,
expression);
}
/**
* Evaluates the specified String expression and makes the first two parameters available inside
* the script bound to variables named 'x' and 'y' respectively, returning the result. For example,
* this code executes without failure:
* <pre class="groovyTestCase">
* assert Eval.xy(2, 4, ' x * y + 2') == 10
* </pre>
* @param expression the Groovy expression to evaluate
* @return the result of the expression
* @throws CompilationFailedException if expression is not valid Groovy
*/
public static
Object xy(final
Object x, final
Object y, final
String expression) throws
CompilationFailedException {
Binding b = new
Binding();
b.
setVariable("x",
x);
b.
setVariable("y",
y);
GroovyShell sh = new
GroovyShell(
b);
return
sh.
evaluate(
expression);
}
/**
* Evaluates the specified String expression and makes the first three parameters available inside
* the script bound to variables named 'x', 'y', and 'z' respectively, returning the result. For
* example, this code executes without failure:
* <pre class="groovyTestCase">
* assert Eval.xyz(2, 4, 2, ' x * y + z') == 10
* </pre>
* @param expression the Groovy expression to evaluate
* @return the result of the expression
* @throws CompilationFailedException if expression is not valid Groovy
*/
public static
Object xyz(final
Object x, final
Object y, final
Object z, final
String expression) throws
CompilationFailedException {
Binding b = new
Binding();
b.
setVariable("x",
x);
b.
setVariable("y",
y);
b.
setVariable("z",
z);
GroovyShell sh = new
GroovyShell(
b);
return
sh.
evaluate(
expression);
}
}