/*
* 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
*
* 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.tools.ant;
import java.util.ArrayList;
import java.util.List;
Helper class for the check of the configuration of a given task.
This class provides methods for making assumptions about the task configuration.
After collecting all violations with assert*
and fail
methods the checkErrors
will throw a BuildException with all collected
messages or does nothing if there wasn't any error.
Example:
public class MyTask extends Task {
...
public void execute() {
TaskConfigurationChecker checker = TaskConfigurationChecker(this);
checker.assertConfig(
srcdir != null,
"Attribute 'srcdir' must be set.
);
checker.assertConfig(
srcdir.exists(),
"Srcdir (" + srcdir + ") must exist."
);
if (someComplexCondition()) {
fail("Complex condition failed.");
}
checker.checkErrors();
}
}
See Also:
/**
* <p>Helper class for the check of the configuration of a given task.
* This class provides methods for making assumptions about the task configuration.
* After collecting all violations with <code>assert*</code> and <code>fail</code>
* methods the <code>checkErrors</code> will throw a BuildException with all collected
* messages or does nothing if there wasn't any error.</p>
*
* <p>Example:</p>
*
* <pre>
* public class MyTask extends Task {
* ...
* public void execute() {
* TaskConfigurationChecker checker = TaskConfigurationChecker(this);
* checker.assertConfig(
* srcdir != null,
* "Attribute 'srcdir' must be set.
* );
* checker.assertConfig(
* srcdir.exists(),
* "Srcdir (" + srcdir + ") must exist."
* );
* if (someComplexCondition()) {
* fail("Complex condition failed.");
* }
* checker.checkErrors();
* }
* }
* </pre>
*
* @see <a href="https://martinfowler.com/eaaDev/Notification.html">Notification Pattern</a>
*/
public class TaskConfigurationChecker {
List of all collected error messages. /** List of all collected error messages. */
private List<String> errors = new ArrayList<>();
Task for which the configuration should be checked. /** Task for which the configuration should be checked. */
private final Task task;
Constructor.
Params: - task – which task should be checked
/**
* Constructor.
* @param task which task should be checked
*/
public TaskConfigurationChecker(Task task) {
this.task = task;
}
Asserts that a condition is true.
Params: - condition – which condition to check
- errormessage – errormessage to throw if a condition failed
/**
* Asserts that a condition is true.
* @param condition which condition to check
* @param errormessage errormessage to throw if a condition failed
*/
public void assertConfig(boolean condition, String errormessage) {
if (!condition) {
errors.add(errormessage);
}
}
Registers an error.
Params: - errormessage – the message for the registered error
/**
* Registers an error.
* @param errormessage the message for the registered error
*/
public void fail(String errormessage) {
errors.add(errormessage);
}
Checks if there are any collected errors and throws a BuildException
with all messages if there was one or more.
Throws: - BuildException – if one or more errors were registered
/**
* Checks if there are any collected errors and throws a BuildException
* with all messages if there was one or more.
* @throws BuildException if one or more errors were registered
*/
public void checkErrors() throws BuildException {
if (!errors.isEmpty()) {
StringBuilder sb = new StringBuilder(String.format("Configuration error on <%s>:%n",
task.getTaskName()));
for (String msg : errors) {
sb.append(String.format("- %s%n", msg));
}
throw new BuildException(sb.toString(), task.getLocation());
}
}
}