basevaluecomponent.lzx

<library>
    <include href="base/basecomponent.lzx"/>

    <!--- an abstract class for components that represent a value for data -->
    <class name="basevaluecomponent" extends="basecomponent">
        <!--- the value that this item represents. When selected,
        the parent selection group's value will be set to this value.
        Most subclasses require you to call getValue() to get the
        value of the attribute.  -->
        <attribute name="value" value="null"/>
        <!--- The type of value of the item. Default is 'expression',
             which will attempt to heuristicate the type from the
             value. -->
        <attribute name="type" type="string" value="expression"/>

        <!--- returns the value that is represented by this component
        -->
        <method name="getValue">
            return this.value == null ? this.text : this.value;
        </method>

        <!--- TODO: [2008-11-14 ptw] There needs to be a simpler way
             to declare simple dependencies like this in LZX
             @access private
        -->
        <method name="$lzc$getValue_dependencies" args="who, self">
          // Since we don't know which one of these getValue will
          // return, we have to depend on both of them
          return [this, 'value', this, 'text'];
        </method>

        <!--- Set `value` according to `type` from a String

              Used to set a typed value from a string representation.

              @param String data: the string representation of `value` (according to `type`).
              @param String type: (optional) the name of the type to use, defaults to `this.type`
        -->
        <method name="acceptValue" args="data, type=null">
          if (type == null) type = this.type;
          // Some subclasses (e.g., textlistitem) want to see the
          // value as text, so we have to call the super method
          super.acceptValue(data, type)
          // This is the main feature of this subclass, to parse the
          // textual data into a value of the proper type
          this.acceptAttribute('value', type, data);
        </method>

        <!--- Return `value` according to `type` as a String

              Used to get a string representation of a typed value.

              @param String type: (optional) the name of the type to use, defaults to `this.type`
              @return String: the string representation of `value` (according to `type`)
        -->
        <method name="presentValue" args="type=null">
          if (type == null) type = this.type;
          // subclasses may override getValue
          return lz.Type.presentTypeValue(type, this.getValue(), this, 'value');
        </method>
        <!--- TODO: [2008-11-14 ptw] There needs to be a simpler way
             to declare simple dependencies like this in LZX
             @access private
        -->
        <method name="$lzc$presentValue_dependencies" args="who, self, type=null">
          // Our dependencies are just the dependencies of
          // getValue and a dependency on our type
          return [this, 'type'].concat(this.$lzc$getValue_dependencies(who, self));
        </method>

        <doc>
          <tag name="shortdesc"><text>an abstract class for components which represent data</text></tag>
          <text>
            <p>
            This abstract class provides a value attribute with data binding to a specific
            valuedatapath.
            </p>
          </text>
        </doc>
    </class>
</library>
<!-- * X_LZ_COPYRIGHT_BEGIN ***************************************************
* Copyright 2001-2010 Laszlo Systems, Inc.  All Rights Reserved.              *
* Use is subject to license terms.                                            *
* X_LZ_COPYRIGHT_END ****************************************************** -->
<!-- @LZX_VERSION@                                                         -->