http://www.eclipse.org/platform: Expression Language (Eclipse Foundation) 
Copyright (c) 2000, 2008 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation

/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.expressions;

import org.eclipse.core.runtime.Assert;


An evaluation result represents the result of an expression
evaluation. There are exact three instances of evaluation
result. They are: FALSE, TRUE and
NOT_LOADED. NOT_LOADED represents
the fact that an expression couldn't be evaluated since a
plug-in providing certain test expressions isn't loaded yet.


In addition the class implements the three operation and
, or and not. The operation are
defined as follows:




  The AND operation:
  
    
    
    
    
  
  
    

      AND
      FALSE
      TRUE
      NOT_LOADED
    

    

      FALSE
      FALSE
      FALSE
      FALSE
    

    

      TRUE
      FALSE
      TRUE
      NOT_LOADED
    

    

      NOT_LOADED
      FALSE
      NOT_LOADED
      NOT_LOADED
    

  






  The OR operation:
  
    
    
    
    
  
  
    

      OR
      FALSE
      TRUE
      NOT_LOADED
    

    

      FALSE
      FALSE
      TRUE
      NOT_LOADED
    

    

      TRUE
      TRUE
      TRUE
      TRUE
    

    

      NOT_LOADED
      NOT_LOADED
      TRUE
      NOT_LOADED
    

  






  The NOT operation:
  
    
    
    
    
  
  
    

      NOT
      FALSE
      TRUE
      NOT_LOADED
    

    

      
      TRUE
      FALSE
      NOT_LOADED
    

  




The class is not intended to be subclassed by clients.



Since:3.0
@noextendThis class is not intended to be subclassed by clients.
/**
 * An evaluation result represents the result of an expression
 * evaluation. There are exact three instances of evaluation
 * result. They are: <code>FALSE</code>, <code>TRUE</code> and
 * <code>NOT_LOADED</code>. <code>NOT_LOADED</code> represents
 * the fact that an expression couldn't be evaluated since a
 * plug-in providing certain test expressions isn't loaded yet.
 * <p>
 * In addition the class implements the three operation <code>and
 * </code>, <code>or</code> and <code>not</code>. The operation are
 * defined as follows:
 * </p>
 * <table border="1" style="text-align: center;">
 *   <caption>The AND operation:</caption>
 *   <colgroup>
 *     <col style="width:120;">
 *     <col style="width:120;">
 *     <col style="width:120;">
 *     <col style="width:120;">
 *   </colgroup>
 *   <tbody>
 *     <tr>
 *       <td style="font-style: italic;">AND</td>
 *       <td>FALSE</td>
 *       <td>TRUE</td>
 *       <td>NOT_LOADED</td>
 *     </tr>
 *     <tr>
 *       <td>FALSE</td>
 *       <td>FALSE</td>
 *       <td>FALSE</td>
 *       <td>FALSE</td>
 *     </tr>
 *     <tr>
 *       <td>TRUE</td>
 *       <td>FALSE</td>
 *       <td>TRUE</td>
 *       <td>NOT_LOADED</td>
 *     </tr>
 *     <tr>
 *       <td>NOT_LOADED</td>
 *       <td>FALSE</td>
 *       <td>NOT_LOADED</td>
 *       <td>NOT_LOADED</td>
 *     </tr>
 *   </tbody>
 * </table>
 * <br>
 * <table border="1" style="text-align: center;">
 *   <caption>The OR operation:</caption>
 *   <colgroup>
 *     <col style="width:120;">
 *     <col style="width:120;">
 *     <col style="width:120;">
 *     <col style="width:120;">
 *   </colgroup>
 *   <tbody>
 *     <tr>
 *       <td style="font-style: italic;">OR</td>
 *       <td>FALSE</td>
 *       <td>TRUE</td>
 *       <td>NOT_LOADED</td>
 *     </tr>
 *     <tr>
 *       <td>FALSE</td>
 *       <td>FALSE</td>
 *       <td>TRUE</td>
 *       <td>NOT_LOADED</td>
 *     </tr>
 *     <tr>
 *       <td>TRUE</td>
 *       <td>TRUE</td>
 *       <td>TRUE</td>
 *       <td>TRUE</td>
 *     </tr>
 *     <tr>
 *       <td>NOT_LOADED</td>
 *       <td>NOT_LOADED</td>
 *       <td>TRUE</td>
 *       <td>NOT_LOADED</td>
 *     </tr>
 *   </tbody>
 * </table>
 * <br>
 * <table border="1" style="text-align: center;">
 *   <caption>The NOT operation:</caption>
 *   <colgroup>
 *     <col style="width:120;">
 *     <col style="width:120;">
 *     <col style="width:120;">
 *     <col style="width:120;">
 *   </colgroup>
 *   <tbody>
 *     <tr>
 *       <td style="font-style: italic;">NOT</td>
 *       <td>FALSE</td>
 *       <td>TRUE</td>
 *       <td>NOT_LOADED</td>
 *     </tr>
 *     <tr>
 *       <td></td>
 *       <td>TRUE</td>
 *       <td>FALSE</td>
 *       <td>NOT_LOADED</td>
 *     </tr>
 *   </tbody>
 * </table>
 *
 * <p>
 * The class is not intended to be subclassed by clients.
 * </p>
 * @since 3.0
 *
 * @noextend This class is not intended to be subclassed by clients.
 */
public class EvaluationResult {

	private int fValue;

	private static final int FALSE_VALUE= 0;
	private static final int TRUE_VALUE= 1;
	private static final int NOT_LOADED_VALUE= 2;

	
The evaluation result representing the value FALSE 
/** The evaluation result representing the value FALSE */
	public static final EvaluationResult FALSE= new EvaluationResult(FALSE_VALUE);
	
The evaluation result representing the value TRUE 
/** The evaluation result representing the value TRUE */
	public static final EvaluationResult TRUE= new EvaluationResult(TRUE_VALUE);
	
The evaluation result representing the value NOT_LOADED 
/** The evaluation result representing the value NOT_LOADED */
	public static final EvaluationResult NOT_LOADED= new EvaluationResult(NOT_LOADED_VALUE);

	private static final EvaluationResult[][] AND= new EvaluationResult[][] {
						// FALSE	//TRUE		//NOT_LOADED
		/* FALSE   */ { FALSE,		FALSE,		FALSE		},
		/* TRUE    */ { FALSE,		TRUE,		NOT_LOADED	},
		/* PNL     */ { FALSE,		NOT_LOADED, NOT_LOADED	},
	};

	private static final EvaluationResult[][] OR= new EvaluationResult[][] {
						// FALSE	//TRUE	//NOT_LOADED
		/* FALSE   */ { FALSE,		TRUE,	NOT_LOADED	},
		/* TRUE    */ { TRUE,		TRUE,	TRUE		},
		/* PNL     */ { NOT_LOADED,	TRUE, 	NOT_LOADED	},
	};

	private static final EvaluationResult[] NOT= new EvaluationResult[] {
		//FALSE		//TRUE	//NOT_LOADED
		TRUE,		FALSE,	NOT_LOADED
	};

	/*
	 * No instances outside of <code>EvaluationResult</code>
	 */
	private EvaluationResult(int value) {
		fValue= value;
	}

	
Returns an EvaluationResult whose value is this && other).

Params:
  • other – the right hand side of the and operation.
Returns:this && other as defined by the evaluation result
/**
	 * Returns an <code>EvaluationResult</code> whose value is <code>this &amp;&amp; other)</code>.
	 *
	 * @param other the right hand side of the and operation.
	 *
	 * @return <code>this &amp;&amp; other</code> as defined by the evaluation result
	 */
	public EvaluationResult and(EvaluationResult other) {
		return AND[fValue][other.fValue];
	}

	
Returns an EvaluationResult whose value is this || other).

Params:
  • other – the right hand side of the or operation.
Returns:this || other as defined by the evaluation result
/**
	 * Returns an <code>EvaluationResult</code> whose value is <code>this || other)</code>.
	 *
	 * @param other the right hand side of the or operation.
	 *
	 * @return <code>this || other</code> as defined by the evaluation result
	 */
	public EvaluationResult or(EvaluationResult other) {
		return OR[fValue][other.fValue];
	}

	
Returns the inverted value of this evaluation result

Returns:the inverted value of this evaluation result
/**
	 * Returns the inverted value of this evaluation result
	 *
	 * @return the inverted value of this evaluation result
	 */
	public EvaluationResult not() {
		return NOT[fValue];
	}

	
Returns an evaluation result instance representing the
given boolean value. If the given boolean value is
true then ExpressionResult.TRUE
is returned. If the value is false then 
ExpressionResult.FALSE is returned.

Params:
  • b – a boolean value
Returns:the expression result representing the boolean
 value
/**
	 * Returns an evaluation result instance representing the
	 * given boolean value. If the given boolean value is
	 * <code>true</code> then <code>ExpressionResult.TRUE</code>
	 * is returned. If the value is <code>false</code> then <code>
	 * ExpressionResult.FALSE</code> is returned.
	 *
	 * @param b a boolean value
	 *
	 * @return the expression result representing the boolean
	 *  value
	 */
	public static EvaluationResult valueOf(boolean b) {
		return b ? TRUE : FALSE;
	}

	
Returns a evaluation result instance representing the
given Boolean value. If the given Boolean
 value is true then ExpressionResult.TRUE
is returned. If the value is false then 
ExpressionResult.FALSE is returned.

Params:
  • b – a Boolean value
Returns:the expression result representing the Boolean
 value
/**
	 * Returns a evaluation result instance representing the
	 * given <code>Boolean</code> value. If the given <code>Boolean
	 * </code> value is <code>true</code> then <code>ExpressionResult.TRUE</code>
	 * is returned. If the value is <code>false</code> then <code>
	 * ExpressionResult.FALSE</code> is returned.
	 *
	 * @param b a <code>Boolean</code> value
	 *
	 * @return the expression result representing the <code>Boolean</code>
	 *  value
	 */
	public static EvaluationResult valueOf(Boolean b) {
		return b.booleanValue() ? TRUE : FALSE;
	}

	
For debugging purpose only

Returns:a string representing this object. The result is not
 human readable
/**
	 * For debugging purpose only
	 *
	 * @return a string representing this object. The result is not
	 *  human readable
	 */
	@Override
	public String toString() {
		switch (fValue) {
			case 0:
				return "false"; //$NON-NLS-1$
			case 1:
				return "true"; //$NON-NLS-1$
			case 2:
				return "not_loaded"; //$NON-NLS-1$
		}
		Assert.isTrue(false);
		return null;
	}
}