Ant example source code file (ContainsRegexpSelector.java)

This example Ant source code file (ContainsRegexpSelector.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

bufferedreader, bufferedreader, buildexception, buildexception, containsregexpselector, could, could, exception, inputstream, io, regexp, regularexpression, string, string, stringbuffer

The ContainsRegexpSelector.java source code

/*
 *  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 org.apache.tools.ant.types.selectors;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.types.Parameter;
import org.apache.tools.ant.types.RegularExpression;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.resources.FileResource;
import org.apache.tools.ant.types.resources.selectors.ResourceSelector;
import org.apache.tools.ant.util.regexp.Regexp;

/**
 * Selector that filters files based on a regular expression.
 *
 * @since Ant 1.6
 */
public class ContainsRegexpSelector extends BaseExtendSelector
        implements ResourceSelector {

    private String userProvidedExpression = null;
    private RegularExpression myRegExp = null;
    private Regexp myExpression = null;
    /** Key to used for parameterized custom selector */
    public static final String EXPRESSION_KEY = "expression";

    /**
     * Creates a new <code>ContainsRegexpSelector instance.
     */
    public ContainsRegexpSelector() {
    }

    /**
     * @return a string describing this object
     */
    public String toString() {
        StringBuffer buf = new StringBuffer(
                "{containsregexpselector expression: ");
        buf.append(userProvidedExpression);
        buf.append("}");
        return buf.toString();
    }

    /**
     * The regular expression used to search the file.
     *
     * @param theexpression this must match a line in the file to be selected.
     */
    public void setExpression(String theexpression) {
        this.userProvidedExpression = theexpression;
    }

    /**
     * When using this as a custom selector, this method will be called.
     * It translates each parameter into the appropriate setXXX() call.
     *
     * @param parameters the complete set of parameters for this selector
     */
    public void setParameters(Parameter[] parameters) {
        super.setParameters(parameters);
        if (parameters != null) {
            for (int i = 0; i < parameters.length; i++) {
                String paramname = parameters[i].getName();
                if (EXPRESSION_KEY.equalsIgnoreCase(paramname)) {
                    setExpression(parameters[i].getValue());
                } else {
                    setError("Invalid parameter " + paramname);
                }
            }
        }
    }

    /**
     * Checks that an expression was specified.
     *
     */
    public void verifySettings() {
        if (userProvidedExpression == null) {
            setError("The expression attribute is required");
        }
    }

    /**
     * Tests a regular expression against each line of text in the file.
     *
     * @param basedir the base directory the scan is being done from
     * @param filename is the name of the file to check
     * @param file is a java.io.File object the selector can use
     * @return whether the file should be selected or not
     */
    public boolean isSelected(File basedir, String filename, File file) {
        return isSelected(new FileResource(file));
    }

    /**
     * Tests a regular expression against each line of text in a Resource.
     *
     * @param r the Resource to check.
     * @return whether the Resource is selected or not
     */
    public boolean isSelected(Resource r) {
        String teststr = null;
        BufferedReader in = null;

        // throw BuildException on error

        validate();

        if (r.isDirectory()) {
            return true;
        }

        if (myRegExp == null) {
            myRegExp = new RegularExpression();
            myRegExp.setPattern(userProvidedExpression);
            myExpression = myRegExp.getRegexp(getProject());
        }

        try {
            in = new BufferedReader(new InputStreamReader(r.getInputStream()));
        } catch (Exception e) {
            throw new BuildException("Could not get InputStream from "
                    + r.toLongString(), e);
        }
        try {
            teststr = in.readLine();

            while (teststr != null) {

                if (myExpression.matches(teststr)) {
                    return true;
                }
                teststr = in.readLine();
            }

            return false;
        } catch (IOException ioe) {
            throw new BuildException("Could not read " + r.toLongString());
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (Exception e) {
                    throw new BuildException("Could not close "
                                             + r.toLongString());
                }
            }
        }
    }
}