/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwtx.jface.text.templates.TemplateContext;

import dwtx.jface.text.templates.SimpleTemplateVariableResolver; // packageimport
import dwtx.jface.text.templates.TemplateBuffer; // packageimport
import dwtx.jface.text.templates.TemplateContextType; // packageimport
import dwtx.jface.text.templates.Template; // packageimport
import dwtx.jface.text.templates.TemplateVariable; // packageimport
import dwtx.jface.text.templates.PositionBasedCompletionProposal; // packageimport
import dwtx.jface.text.templates.TemplateException; // packageimport
import dwtx.jface.text.templates.TemplateTranslator; // packageimport
import dwtx.jface.text.templates.DocumentTemplateContext; // packageimport
import dwtx.jface.text.templates.GlobalTemplateVariables; // packageimport
import dwtx.jface.text.templates.InclusivePositionUpdater; // packageimport
import dwtx.jface.text.templates.TemplateProposal; // packageimport
import dwtx.jface.text.templates.ContextTypeRegistry; // packageimport
import dwtx.jface.text.templates.JFaceTextTemplateMessages; // packageimport
import dwtx.jface.text.templates.TemplateCompletionProcessor; // packageimport
import dwtx.jface.text.templates.TextTemplateMessages; // packageimport
import dwtx.jface.text.templates.TemplateVariableType; // packageimport
import dwtx.jface.text.templates.TemplateVariableResolver; // packageimport


import dwt.dwthelper.utils;

import dwtx.dwtxhelper.Collection;


import dwtx.jface.text.BadLocationException;

/**
 * Provides the context for a <code>Template</code> being resolved. Keeps track
 * of resolved variables.
 * <p>
 * Clients may extend this class.
 * </p>
 *
 * @since 3.0
 */
public abstract class TemplateContext {

    /** The context type of this context */
    private const TemplateContextType fContextType;
    /** Additional variables. */
    private const Map fVariables= new HashMap();
    /** A flag to indicate that the context should not be modified. */
    private bool fReadOnly;

    /**
     * Creates a template context of a particular context type.
     *
     * @param contextType the context type of this context
     */
    protected this(TemplateContextType contextType) {
        fContextType= contextType;
        fReadOnly= true;
    }

    /**
     * Returns the context type of this context.
     *
     * @return the context type of this context
     */
    public TemplateContextType getContextType() {
        return fContextType;
    }

    /**
     * Sets or clears the read-only flag.
     *
     * @param readOnly the new read-only state
     */
    public void setReadOnly(bool readOnly) {
        fReadOnly= readOnly;
    }

    /**
     * Returns <code>true</code> if the receiver is read-only, <code>false</code> otherwise.
     *
     * @return <code>true</code> if the receiver is read-only, <code>false</code> otherwise
     */
    public bool isReadOnly() {
        return fReadOnly;
    }

    /**
     * Defines the value of a variable.
     *
     * @param name the name of the variable
     * @param value the value of the variable, <code>null</code> to un-define a variable
     */
    public void setVariable(String name, String value) {
        fVariables.put(name, value);
    }

    /**
     * Returns the value of a defined variable.
     *
     * @param name the name of the variable
     * @return returns the value of the variable, <code>null</code> if the variable was not defined
     */
    public String getVariable(String name) {
        return cast(String) fVariables.get(name);
    }

    /**
     * Evaluates the template in this context and returns a template buffer.
     * <p>
     * Evaluation means translating the template into a <code>TemplateBuffer</code>,
     * resolving the defined variables in this context and possibly formatting
     * the resolved buffer.</p>
     *
     * @param template the template to evaluate
     * @return returns the buffer with the evaluated template or <code>null</code> if the buffer could not be created
     * @throws BadLocationException if evaluation fails due to concurrently changed documents etc.
     * @throws TemplateException if the template specification is not valid
     */
    public abstract TemplateBuffer evaluate(Template template_);

    /**
     * Tests if the specified template can be evaluated in this context.
     * <p>Examples are templates defined for a different context (e.g. a javadoc
     * template cannot be evaluated in Java context).</p>
     *
     * @param template the <code>Template</code> to check
     * @return <code>true</code> if <code>template</code> can be evaluated
     *         in this context, <code>false</code> otherwise
     */
    public abstract bool canEvaluate(Template template_);

}