/*******************************************************************************
* Copyright (c) 2000, 2007 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
*******************************************************************************/
package org.eclipse.core.internal.variables;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.variables.IValueVariable;
import org.eclipse.core.variables.IValueVariableInitializer;
import org.eclipse.core.variables.VariablesPlugin;
import org.eclipse.osgi.util.NLS;
/**
* Implementation of a value variable.
*/
public class ContributedValueVariable extends StringVariable implements IValueVariable {
/**
* Variable value or <code>null</code> if none
*/
private String fValue;
/**
* Whether this variable's value has been initialized
*/
private boolean fInitialized = false;
/**
* Whether this variable is read only. If true, users cannot change the value.
*/
private boolean fReadOnly;
/**
* Constructs a new value variable with the given name, description, read only
* property and associated configuration element. The value will be initialized
* from the configuration element the first time getValue() is called.
*
* @param name variable name
* @param description variable description or <code>null</code>
* @param readOnly whether the variable should be a read only variable
* @param configurationElement configuration element
*/
public ContributedValueVariable(String name, String description, boolean readOnly, IConfigurationElement configurationElement) {
super(name, description, configurationElement);
fReadOnly = readOnly;
}
/* (non-Javadoc)
* @see org.eclipse.core.variables.IValueVariable#setValue(java.lang.String)
*/
public void setValue(String value) {
if (!isReadOnly() || !isInitialized()){
fValue = value;
setInitialized(true);
StringVariableManager.getDefault().notifyChanged(this);
}
}
/* (non-Javadoc)
* @see org.eclipse.core.variables.IValueVariable#getValue()
*/
public String getValue() {
if (!isInitialized()) {
initialize();
}
return fValue;
}
/**
* Initialize this variable's value from the configuration element.
*/
private void initialize() {
if (getConfigurationElement() != null) {
// check for a explicit value specified in plug-in XML
String value = getConfigurationElement().getAttribute("initialValue"); //$NON-NLS-1$
if (value == null) {
// check for initializer
String className = getConfigurationElement().getAttribute("initializerClass"); //$NON-NLS-1$
if (className != null) {
try {
Object object = getConfigurationElement().createExecutableExtension("initializerClass"); //$NON-NLS-1$
if (object instanceof IValueVariableInitializer) {
IValueVariableInitializer initializer = (IValueVariableInitializer)object;
initializer.initialize(this);
} else {
VariablesPlugin.logMessage(NLS.bind("Unable to initialize variable {0} - initializer must be an instance of IValueVariableInitializer.", new String[]{getName()}), null); //$NON-NLS-1$
}
} catch (CoreException e) {
VariablesPlugin.logMessage(NLS.bind("Unable to initialize variable {0}",new String[]{getName()}), e); //$NON-NLS-1$
}
}
} else {
setValue(value);
}
}
setInitialized(true);
}
/**
* Returns whether this variable has been initialized with a value by one of:
* <ul>
* <li><code>setValue(String)</code></li>
* <li>its configuration element's <code>initialValue</code> attribute</li>
* <li>its configuration element's initializer</li>
* </ul>
* @return whether this variable has been initialized with a value
*/
protected boolean isInitialized() {
return fInitialized;
}
/**
* Sets whether this variable has been initialized with a value.
*
* @param initialized whether this variable has been initialized
*/
protected void setInitialized(boolean initialized) {
fInitialized = initialized;
}
/* (non-Javadoc)
* @see org.eclipse.core.variables.IValueVariable#isReadOnly()
*/
public boolean isReadOnly() {
return fReadOnly;
}
/* (non-Javadoc)
* @see org.eclipse.core.variables.IValueVariable#isContributed()
*/
public boolean isContributed() {
return getConfigurationElement() != null;
}
}