org.stringtemplate.v4.misc.Aggregate Maven / Gradle / Ivy
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/*
* [The "BSD license"]
* Copyright (c) 2011 Terence Parr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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*/
package org.stringtemplate.v4.misc;
import java.util.HashMap;
/** An automatically created aggregate of properties.
*
* I often have lists of things that need to be formatted, but the list
* items are actually pieces of data that are not already in an object. I
* need ST to do something like:
*
* Ter=3432
* Tom=32234
* ....
*
* using template:
*
* {@code $items:{it.name$=$it.type$}$}
*
* This example will call {@code getName()} on the objects in items attribute, but
* what if they aren't objects? I have perhaps two parallel arrays
* instead of a single array of objects containing two fields. One
* solution is allow {@code Map}s to be handled like properties so that {@code it.name}
* would fail {@code getName()} but then see that it's a {@code Map} and do
* {@code it.get("name")} instead.
*
* This very clean approach is espoused by some, but the problem is that
* it's a hole in my separation rules. People can put the logic in the
* view because you could say: "go get bob's data" in the view:
*
* Bob's Phone: {@code $db.bob.phone$}
*
* A view should not be part of the program and hence should never be able
* to go ask for a specific person's data.
*
* After much thought, I finally decided on a simple solution. I've
* added setAttribute variants that pass in multiple property values,
* with the property names specified as part of the name using a special
* attribute name syntax: {@code "name.{propName1,propName2,...}"}. This
* object is a special kind of {@code HashMap} that hopefully prevents people
* from passing a subclass or other variant that they have created as
* it would be a loophole. Anyway, the {@link AggregateModelAdaptor#getProperty}
* method looks for {@code Aggregate} as a special case and does a {@link #get} instead
* of {@code getPropertyName}.
*/
public class Aggregate {
public HashMap properties = new HashMap();
/** Allow StringTemplate to add values, but prevent the end
* user from doing so.
*/
protected void put(String propName, Object propValue) {
properties.put(propName, propValue);
}
public Object get(String propName) {
return properties.get(propName);
}
@Override
public String toString() {
return properties.toString();
}
}