EchoProperties (Apache Ant API)
Date: 2018-07-10

org.apache.tools.ant.taskdefs.optional

## Class EchoProperties

- java.lang.Object
- - org.apache.tools.ant.ProjectComponent
  - - org.apache.tools.ant.Task
    - - org.apache.tools.ant.taskdefs.optional.EchoProperties

- All Implemented Interfaces:
    java.lang.Cloneable

      public class EchoProperties
      extends Task

  Displays all the current properties in the build. The output can be sent to a file if desired.

  Attribute "destfile" defines a file to send the properties to. This can be processed as a standard property file later.

  Attribute "prefix" defines a prefix which is used to filter the properties only those properties starting with this prefix will be echoed.

  By default, the "failonerror" attribute is enabled. If an error occurs while writing the properties to a file, and this attribute is enabled, then a BuildException will be thrown. If disabled, then IO errors will be reported as a log statement, but no error will be thrown.

  Examples:

        <echoproperties  />

  Report the current properties to the log.

        <echoproperties destfile="my.properties" />

  Report the current properties to the file "my.properties", and will fail the build if the file could not be created or written to.

        <echoproperties destfile="my.properties" failonerror="false"
            prefix="ant" />

  Report all properties beginning with 'ant' to the file "my.properties", and will log a message if the file could not be created or written to, but will still allow the build to continue.
  Since:
    Ant 1.5

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `EchoProperties.FormatAttribute` A enumerated type for the format attribute.

  - ### Field Summary

    - ### Fields inherited from class org.apache.tools.ant.Task

      `target, taskName, taskType, wrapper`

    - ### Fields inherited from class org.apache.tools.ant.ProjectComponent

      `description, location, project`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `EchoProperties()`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `addPropertyset(PropertySet ps)` A set of properties to write.
    `void` | `execute()` Run the task.
    `protected void` | `jdkSaveProperties(java.util.Properties props, java.io.OutputStream os, java.lang.String header)` JDK 1.2 allows for the safer method `Properties.store(OutputStream, String)`, which throws an `IOException` on an output error.
    `protected void` | `saveProperties(java.util.Hashtable allProps, java.io.OutputStream os)` Send the key/value pairs in the hashtable to the given output stream.
    `void` | `setDestfile(java.io.File destfile)` Set a file to store the property output.
    `void` | `setFailOnError(boolean failonerror)` If true, the task will fail if an error occurs writing the properties file, otherwise errors are just logged.
    `void` | `setFormat(EchoProperties.FormatAttribute ea)` Set the output format - xml or text.
    `void` | `setPrefix(java.lang.String prefix)` If the prefix is set, then only properties which start with this prefix string will be recorded.
    `void` | `setRegex(java.lang.String regex)` If the regex is set, then only properties whose names match it will be recorded.
    `void` | `setSrcfile(java.io.File file)` Sets the input file.
    `protected void` | `xmlSaveProperties(java.util.Properties props, java.io.OutputStream os)` Output the properties as xml output.

    - ### Methods inherited from class org.apache.tools.ant.Task

      `bindToOwner, getOwningTarget, getRuntimeConfigurableWrapper, getTaskName, getTaskType, getWrapper, handleErrorFlush, handleErrorOutput, handleFlush, handleInput, handleOutput, init, isInvalid, log, log, log, log, maybeConfigure, perform, reconfigure, setOwningTarget, setRuntimeConfigurableWrapper, setTaskName, setTaskType`

    - ### Methods inherited from class org.apache.tools.ant.ProjectComponent

      `clone, getDescription, getLocation, getProject, setDescription, setLocation, setProject`

    - ### Methods inherited from class java.lang.Object

      `equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### EchoProperties

          public EchoProperties()

  - ### Method Detail

    - #### setSrcfile

          public void setSrcfile(java.io.File file)

      Sets the input file.
      Parameters:
        `file` - the input file

    - #### setDestfile

          public void setDestfile(java.io.File destfile)

      Set a file to store the property output. If this is never specified, then the output will be sent to the Ant log.
      Parameters:
        `destfile` - file to store the property output

    - #### setFailOnError

          public void setFailOnError(boolean failonerror)

      If true, the task will fail if an error occurs writing the properties file, otherwise errors are just logged.
      Parameters:
        `failonerror` - `true` if IO exceptions are reported as build exceptions, or `false` if IO exceptions are ignored.

    - #### setPrefix

          public void setPrefix(java.lang.String prefix)

      If the prefix is set, then only properties which start with this prefix string will be recorded. If regex is not set and if this is never set, or it is set to an empty string or `null`, then all properties will be recorded.

      For example, if the attribute is set as:

          <echoproperties  prefix="ant." />

      then the property "ant.home" will be recorded, but "ant-example" will not.
      Parameters:
        `prefix` - The new prefix value

    - #### setRegex

          public void setRegex(java.lang.String regex)

      If the regex is set, then only properties whose names match it will be recorded. If prefix is not set and if this is never set, or it is set to an empty string or `null`, then all properties will be recorded.

      For example, if the attribute is set as:

          <echoproperties  prefix=".*ant.*" />

      then the properties "ant.home" and "user.variant" will be recorded, but "ant-example" will not.
      Parameters:
        `regex` - The new regex value
      Since:
        Ant 1.7

    - #### addPropertyset

          public void addPropertyset(PropertySet ps)

      A set of properties to write.
      Parameters:
        `ps` - the property set to write
      Since:
        Ant 1.6

    - #### setFormat

          public void setFormat(EchoProperties.FormatAttribute ea)

      Set the output format - xml or text.
      Parameters:
        `ea` - an enumerated `FormatAttribute` value

    - #### execute

          public void execute()
                       throws BuildException

      Run the task.
      Overrides:
        `execute` in class `Task`
      Throws:
        `BuildException` - trouble, probably file IO

    - #### saveProperties

          protected void saveProperties(java.util.Hashtable allProps,
                                        java.io.OutputStream os)
                                 throws java.io.IOException,
                                        BuildException

      Send the key/value pairs in the hashtable to the given output stream. Only those properties matching the `prefix` constraint will be sent to the output stream. The output stream will be closed when this method returns.
      Parameters:
        `allProps` - propfile to save
        `os` - output stream
      Throws:
        `java.io.IOException` - on output errors
        `BuildException` - on other errors

    - #### xmlSaveProperties

          protected void xmlSaveProperties(java.util.Properties props,
                                           java.io.OutputStream os)
                                    throws java.io.IOException

      Output the properties as xml output.
      Parameters:
        `props` - the properties to save
        `os` - the output stream to write to (Note this gets closed)
      Throws:
        `java.io.IOException` - on error in writing to the stream

    - #### jdkSaveProperties

          protected void jdkSaveProperties(java.util.Properties props,
                                           java.io.OutputStream os,
                                           java.lang.String header)
                                    throws java.io.IOException

      JDK 1.2 allows for the safer method `Properties.store(OutputStream, String)`, which throws an `IOException` on an output error.
      Parameters:
        `props` - the properties to record
        `os` - record the properties to this output stream
        `header` - prepend this header to the property output
      Throws:
        `java.io.IOException` - on an I/O error during a write.