Ant example source code file (PropertyFile.java)

This example Ant source code file (PropertyFile.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

buildexception, buildexception, decimalformat, default_int_value, default_string_value, entry, entry, enumeratedattribute, enumeratedattribute, io, numberformatexception, parseexception, string, string, text, util, vector

The PropertyFile.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.taskdefs.optional;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.DateFormat;
import java.text.DecimalFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Vector;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.util.FileUtils;
import org.apache.tools.ant.types.EnumeratedAttribute;

/**
 *Modifies settings in a property file.
 *
 * <p>
 *The following is an example of its usage:
 *    <ul><target name="setState">

 *    <ul><property

 *        <ul>name="header"

 *        value="##Generated file - do not modify!"/><br>
 *      <propertyfile file="apropfile.properties" comment="${header}"><br>
 *        <entry key="product.version.major" type="int"  value="5"/><br>
 *        <entry key="product.version.minor" type="int"  value="0"/><br>
 *        <entry key="product.build.major"   type="int"  value="0" /><br>
 *        <entry key="product.build.minor"   type="int"  operation="+" /><br>
 *        <entry key="product.build.date"    type="date" value="now" /><br>
 *        <entry key="intSet" type="int" operation="=" value="681"/><br>
 *        <entry key="intDec" type="int" operation="-"/><br>
 *        <entry key="StringEquals" type="string" value="testValue"/><br>
 *     </propertyfile><br>
 *   </target></ul>

 *
 *The <propertyfile> task must have:<br>
 *    <ul>
file
 *Other parameters are:<br>
 *    <ul>
comment, key, operation, type and value (the final four being
 *            eliminated shortly)</li>
 *
 *The <entry> task must have:<br>
 *    <ul>
key
 *Other parameters are:<br>
 *    <ul>
operation
 *        <li>type
 *        <li>value
 *        <li>default
 *        <li>unit
 *    </ul>
 *
 *If type is unspecified, it defaults to string
 *
 *Parameter values:<br>
 *    <ul>
operation:
 *        <ul>
"=" (set -- default)
 *        <li>"-" (dec)
 *        <li>"+" (inc)
 *
 *    <li>type:
 *        <ul>
"int"
 *        <li>"date"
 *        <li>"string"
 *
 *    <li>value:
 *      <ul>
holds the default value, if the property
 *              was not found in property file</li>
 *          <li>"now" In case of type "date", the
 *              value "now" will be replaced by the current
 *              date/time and used even if a valid date was
 *              found in the property file.</li>
 *
 *
 *String property types can only use the "=" operation.
 *Int property types can only use the "=", "-" or "+" operations.<p>
 *
 *The message property is used for the property file header, with "\\" being
 *a newline delimiter character.
 *
 */
public class PropertyFile extends Task {

    /* ========================================================================
    *
    * Instance variables.
    */

    // Use this to prepend a message to the properties file
    private String              comment;

    private Properties          properties;
    private File                propertyfile;

    private Vector entries = new Vector();

    /* ========================================================================
    *
    * Constructors
    */

    /* ========================================================================
    *
    * Methods
    */

    /**
     * Execute the task.
     * @throws BuildException on error.
     */
    public void execute() throws BuildException {
        checkParameters();
        readFile();
        executeOperation();
        writeFile();
    }

    /**
     * The entry nested element.
     * @return an entry nested element to be configured.
     */
    public Entry createEntry() {
        Entry e = new Entry();
        entries.addElement(e);
        return e;
    }

    private void executeOperation() throws BuildException {
        for (Enumeration e = entries.elements(); e.hasMoreElements();) {
            Entry entry = (Entry) e.nextElement();
            entry.executeOn(properties);
        }
    }

    private void readFile() throws BuildException {
        // Create the PropertyFile
        properties = new Properties();
        try {
            if (propertyfile.exists()) {
                log("Updating property file: "
                    + propertyfile.getAbsolutePath());
                FileInputStream fis = null;
                try {
                    fis = new FileInputStream(propertyfile);
                    BufferedInputStream bis = new BufferedInputStream(fis);
                    properties.load(bis);
                } finally {
                    if (fis != null) {
                        fis.close();
                    }
                }
            } else {
                log("Creating new property file: "
                    + propertyfile.getAbsolutePath());
                FileOutputStream out = null;
                try {
                    out = new FileOutputStream(propertyfile.getAbsolutePath());
                    out.flush();
                } finally {
                    if (out != null) {
                        out.close();
                    }
                }
            }
        } catch (IOException ioe) {
            throw new BuildException(ioe.toString());
        }
    }

    private void checkParameters() throws BuildException {
        if (!checkParam(propertyfile)) {
            throw new BuildException("file token must not be null.", getLocation());
        }
    }

    /**
     * Location of the property file to be edited; required.
     * @param file the property file.
     */
    public void setFile(File file) {
        propertyfile = file;
    }

    /**
     * optional header comment for the file
     * @param hdr the string to use for the comment.
     */
    public void setComment(String hdr) {
        comment = hdr;
    }

    private void writeFile() throws BuildException {
        BufferedOutputStream bos = null;
        try {
            bos = new BufferedOutputStream(new FileOutputStream(propertyfile));
            properties.store(bos, comment);
        } catch (IOException ioe) {
            throw new BuildException(ioe, getLocation());
        } finally {
            FileUtils.close(bos);
        }
    }

    private boolean checkParam(File param) {
        return !(param == null);
    }

    /**
     * Instance of this class represents nested elements of
     * a task propertyfile.
     */
    public static class Entry {
        private static final int DEFAULT_INT_VALUE = 0;
        private static final String DEFAULT_DATE_VALUE = "now";
        private static final String DEFAULT_STRING_VALUE = "";

        private String              key = null;
        private int                 type = Type.STRING_TYPE;
        private int                 operation = Operation.EQUALS_OPER;
        private String              value = null;
        private String              defaultValue = null;
        private String              newValue = null;
        private String              pattern = null;
        private int                 field = Calendar.DATE;

        /**
         * Name of the property name/value pair
         * @param value the key.
         */
        public void setKey(String value) {
            this.key = value;
        }

        /**
         * Value to set (=), to add (+) or subtract (-)
         * @param value the value.
         */
        public void setValue(String value) {
            this.value = value;
        }

        /**
         * operation to apply.
         * "+" or "="
         *(default) for all datatypes; "-" for date and int only)\.
         * @param value the operation enumerated value.
         */
        public void setOperation(Operation value) {
            this.operation = Operation.toOperation(value.getValue());
        }

        /**
         * Regard the value as : int, date or string (default)
         * @param value the type enumerated value.
         */
        public void setType(Type value) {
            this.type = Type.toType(value.getValue());
        }

        /**
         * Initial value to set for a property if it is not
         * already defined in the property file.
         * For type date, an additional keyword is allowed: "now"
         * @param value the default value.
         */
        public void setDefault(String value) {
            this.defaultValue = value;
        }

        /**
         * For int and date type only. If present, Values will
         * be parsed and formatted accordingly.
         * @param value the pattern to use.
         */
        public void setPattern(String value) {
            this.pattern = value;
        }

        /**
         * The unit of the value to be applied to date +/- operations.
         *            Valid Values are:
         *            <ul>
         *               <li>millisecond
         *               <li>second
         *               <li>minute
         *               <li>hour
         *               <li>day (default)
         *               <li>week
         *               <li>month
         *               <li>year
         *            </ul>
         *            This only applies to date types using a +/- operation.
         * @param unit the unit enumerated value.
         * @since Ant 1.5
         */
        public void setUnit(PropertyFile.Unit unit) {
            field = unit.getCalendarField();
        }

        /**
         * Apply the nested element to the properties.
         * @param props the properties to apply the entry on.
         * @throws BuildException if there is an error.
         */
        protected void executeOn(Properties props) throws BuildException {
            checkParameters();

            // type may be null because it wasn't set
            String oldValue = (String) props.get(key);
            try {
                if (type == Type.INTEGER_TYPE) {
                    executeInteger(oldValue);
                } else if (type == Type.DATE_TYPE) {
                    executeDate(oldValue);
                } else if (type == Type.STRING_TYPE) {
                    executeString(oldValue);
                } else {
                    throw new BuildException("Unknown operation type: "
                        + type);
                }
            } catch (NullPointerException npe) {
                // Default to string type
                // which means do nothing
                npe.printStackTrace();
            }

            if (newValue == null) {
                newValue = "";
            }

            // Insert as a string by default
            props.put(key, newValue);
        }

        /**
        * Handle operations for type <code>date.
        *
        * @param oldValue the current value read from the property file or
        *                 <code>null if the key was
        *                 not contained in the property file.
        */
        private void executeDate(String oldValue) throws BuildException {
            Calendar currentValue = Calendar.getInstance();

            if (pattern == null) {
              pattern = "yyyy/MM/dd HH:mm";
            }
            DateFormat fmt = new SimpleDateFormat(pattern);

            String currentStringValue = getCurrentValue(oldValue);
            if (currentStringValue == null) {
                currentStringValue = DEFAULT_DATE_VALUE;
            }

            if ("now".equals(currentStringValue)) {
                currentValue.setTime(new Date());
            } else {
                try {
                    currentValue.setTime(fmt.parse(currentStringValue));
                } catch (ParseException pe)  {
                    // swallow
                }
            }

            if (operation != Operation.EQUALS_OPER) {
                int offset = 0;
                try {
                    offset = Integer.parseInt(value);
                    if (operation == Operation.DECREMENT_OPER) {
                        offset = -1 * offset;
                    }
                } catch (NumberFormatException e) {
                    throw new BuildException("Value not an integer on " + key);
                }
                currentValue.add(field, offset);
            }

            newValue = fmt.format(currentValue.getTime());
        }


        /**
        * Handle operations for type <code>int.
        *
        * @param oldValue the current value read from the property file or
        *                 <code>null if the key was
        *                 not contained in the property file.
        */
        private void executeInteger(String oldValue) throws BuildException {
            int currentValue = DEFAULT_INT_VALUE;
            int newV  = DEFAULT_INT_VALUE;


            DecimalFormat fmt = (pattern != null) ? new DecimalFormat(pattern)
                                                    : new DecimalFormat();
            try {
                String curval = getCurrentValue(oldValue);
                if (curval != null) {
                    currentValue = fmt.parse(curval).intValue();
                } else {
                    currentValue = 0;
                }
            } catch (NumberFormatException nfe) {
                // swallow
            } catch (ParseException pe)  {
                // swallow
            }

            if (operation == Operation.EQUALS_OPER) {
                newV = currentValue;
            } else {
                int operationValue = 1;
                if (value != null) {
                    try {
                        operationValue = fmt.parse(value).intValue();
                    } catch (NumberFormatException nfe) {
                        // swallow
                    } catch (ParseException pe)  {
                        // swallow
                    }
                }

                if (operation == Operation.INCREMENT_OPER) {
                    newV = currentValue + operationValue;
                } else if (operation == Operation.DECREMENT_OPER) {
                    newV = currentValue - operationValue;
                }
            }

            this.newValue = fmt.format(newV);
        }

        /**
        * Handle operations for type <code>string.
        *
        * @param oldValue the current value read from the property file or
        *                 <code>null if the key was
        *                 not contained in the property file.
        */
        private void executeString(String oldValue) throws BuildException {
            String newV  = DEFAULT_STRING_VALUE;

            String currentValue = getCurrentValue(oldValue);

            if (currentValue == null) {
                currentValue = DEFAULT_STRING_VALUE;
            }

            if (operation == Operation.EQUALS_OPER) {
                newV = currentValue;
            } else if (operation == Operation.INCREMENT_OPER) {
                newV = currentValue + value;
            }
            this.newValue = newV;
        }

        /**
         * Check if parameter combinations can be supported
         * @todo make sure the 'unit' attribute is only specified on date
         *      fields
         */
        private void checkParameters() throws BuildException {
            if (type == Type.STRING_TYPE
                && operation == Operation.DECREMENT_OPER) {
                throw new BuildException("- is not supported for string "
                    + "properties (key:" + key + ")");
            }
            if (value == null && defaultValue == null) {
                throw new BuildException("\"value\" and/or \"default\" "
                    + "attribute must be specified (key:" + key + ")");
            }
            if (key == null) {
                throw new BuildException("key is mandatory");
            }
            if (type == Type.STRING_TYPE && pattern != null) {
                throw new BuildException("pattern is not supported for string "
                    + "properties (key:" + key + ")");
            }
        }

        private String getCurrentValue(String oldValue) {
            String ret = null;
            if (operation == Operation.EQUALS_OPER) {
                // If only value is specified, the property is set to it
                // regardless of its previous value.
                if (value != null && defaultValue == null) {
                    ret = value;
                }

                // If only default is specified and the property previously
                // existed in the property file, it is unchanged.
                if (value == null && defaultValue != null && oldValue != null) {
                    ret = oldValue;
                }

                // If only default is specified and the property did not
                // exist in the property file, the property is set to default.
                if (value == null && defaultValue != null && oldValue == null) {
                    ret = defaultValue;
                }

                // If value and default are both specified and the property
                // previously existed in the property file, the property
                // is set to value.
                if (value != null && defaultValue != null && oldValue != null) {
                    ret = value;
                }

                // If value and default are both specified and the property
                // did not exist in the property file, the property is set
                // to default.
                if (value != null && defaultValue != null && oldValue == null) {
                    ret = defaultValue;
                }
            } else {
                ret = (oldValue == null) ? defaultValue : oldValue;
            }

            return ret;
        }

        /**
         * Enumerated attribute with the values "+", "-", "="
         */
        public static class Operation extends EnumeratedAttribute {

            // Property type operations
            /** + */
            public static final int INCREMENT_OPER =   0;
            /** - */
            public static final int DECREMENT_OPER =   1;
            /** = */
            public static final int EQUALS_OPER =      2;

            /** {@inheritDoc}. */
            public String[] getValues() {
                return new String[] {"+", "-", "="};
            }

            /**
             * Convert string to index.
             * @param oper the string to convert.
             * @return the index.
             */
            public static int toOperation(String oper) {
                if ("+".equals(oper)) {
                    return INCREMENT_OPER;
                } else if ("-".equals(oper)) {
                    return DECREMENT_OPER;
                }
                return EQUALS_OPER;
            }
        }

        /**
         * Enumerated attribute with the values "int", "date" and "string".
         */
        public static class Type extends EnumeratedAttribute {

            // Property types
            /** int */
            public static final int INTEGER_TYPE =     0;
            /** date */
            public static final int DATE_TYPE =        1;
            /** string */
            public static final int STRING_TYPE =      2;

            /** {@inheritDoc} */
            public String[] getValues() {
                return new String[] {"int", "date", "string"};
            }

            /**
             * Convert string to index.
             * @param type the string to convert.
             * @return the index.
             */
            public static int toType(String type) {
                if ("int".equals(type)) {
                    return INTEGER_TYPE;
                } else if ("date".equals(type)) {
                    return DATE_TYPE;
                }
                return STRING_TYPE;
            }
        }
    }

    /**
     * Borrowed from Tstamp
     * @todo share all this time stuff across many tasks as a datetime datatype
     * @since Ant 1.5
     */
    public static class Unit extends EnumeratedAttribute {

        private static final String MILLISECOND = "millisecond";
        private static final String SECOND = "second";
        private static final String MINUTE = "minute";
        private static final String HOUR = "hour";
        private static final String DAY = "day";
        private static final String WEEK = "week";
        private static final String MONTH = "month";
        private static final String YEAR = "year";

        private static final String[] UNITS
            = {MILLISECOND, SECOND, MINUTE, HOUR,
               DAY, WEEK, MONTH, YEAR };

        private Map calendarFields = new HashMap();

        /** no arg constructor */
        public Unit() {
            calendarFields.put(MILLISECOND,
                                    new Integer(Calendar.MILLISECOND));
            calendarFields.put(SECOND, new Integer(Calendar.SECOND));
            calendarFields.put(MINUTE, new Integer(Calendar.MINUTE));
            calendarFields.put(HOUR, new Integer(Calendar.HOUR_OF_DAY));
            calendarFields.put(DAY, new Integer(Calendar.DATE));
            calendarFields.put(WEEK, new Integer(Calendar.WEEK_OF_YEAR));
            calendarFields.put(MONTH, new Integer(Calendar.MONTH));
            calendarFields.put(YEAR, new Integer(Calendar.YEAR));
        }

        /**
         * Convert the value to a Calendar field index.
         * @return the calander value.
         */
        public int getCalendarField() {
            String key = getValue().toLowerCase();
            Integer i = (Integer) calendarFields.get(key);
            return i.intValue();
        }

        /** {@inheritDoc}. */
        public String[] getValues() {
            return UNITS;
        }
    }
}