Copyright (c) 2000, 2005 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, 2005 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.jface.text.templates;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.core.runtime.IAdaptable;

import org.eclipse.jface.text.BadLocationException;

Provides the context for a Template being resolved. Keeps track
of resolved variables.

Clients may extend this class.

Since:
3.0/**
 * 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 implements IAdaptable {

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

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

	
Returns the context type of this context.
Returns:
the context type of this context/**
	 * 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.
Params:
readOnly – the new read-only state/**
	 * Sets or clears the read-only flag.
	 *
	 * @param readOnly the new read-only state
	 */
	public void setReadOnly(boolean readOnly) {
		fReadOnly= readOnly;
	}

	
Returns true if the receiver is read-only, false otherwise.
Returns:
true if the receiver is read-only, false otherwise/**
	 * 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 boolean isReadOnly() {
		return fReadOnly;
	}

	
Defines the value of a variable.
Params:
name – the name of the variable
value – the value of the variable, null to un-define a variable/**
	 * 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.
Params:
name – the name of the variable
Returns:
returns the value of the variable, null if the variable was not defined/**
	 * 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 fVariables.get(name);
	}

	
Evaluates the template in this context and returns a template buffer.

Evaluation means translating the template into a TemplateBuffer,
resolving the defined variables in this context and possibly formatting
the resolved buffer.
Params:
template – the template to evaluate
Throws:
BadLocationException – if evaluation fails due to concurrently changed documents etc.
TemplateException – if the template specification is not valid
Returns:
returns the buffer with the evaluated template or null if the buffer could not be created/**
	 * 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) throws BadLocationException, TemplateException;

	
Tests if the specified template can be evaluated in this context.
Examples are templates defined for a different context (e.g. a javadoc
template cannot be evaluated in Java context).
Params:
template – the Template to check
Returns:
true if template can be evaluated
        in this context, false otherwise/**
	 * 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 boolean canEvaluate(Template template);
	
	
Default implementation does nothing, clients can override to provide adapters.
{@inheritDoc}
/**
	 * Default implementation does nothing, clients can override to provide adapters.
	 * {@inheritDoc}
	 */
	@Override
	public <T> T getAdapter(Class<T> adapter) {
		return null;
	}

}