org.eclipse.ui.ActiveShellExpression Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2005, 2015 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.ui;
import org.eclipse.core.expressions.EvaluationResult;
import org.eclipse.core.expressions.Expression;
import org.eclipse.core.expressions.ExpressionInfo;
import org.eclipse.core.expressions.IEvaluationContext;
import org.eclipse.swt.widgets.Shell;
/**
*
* An expression that checks the active shell variable. The variable name is
* ISources.ACTIVE_SHELL_NAME and falls back to
* ISources.ACTIVE_WORKBENCH_WINDOW. That is, if the active
* shell doesn't match, then it will be allowed to match the active workbench
* window.
*
*
* @since 3.1
*/
public final class ActiveShellExpression extends Expression {
/**
* The seed for the hash code for all schemes.
*/
private static final int HASH_INITIAL = ActiveShellExpression.class
.getName().hashCode();
/**
* The sources value to use with this expression.
*/
public static final int SOURCES = ISources.ACTIVE_SHELL
| ISources.ACTIVE_WORKBENCH_WINDOW;
/**
* The shell that must be active for this expression to evaluate to
* true. If this value is null, then any
* shell may be active.
*/
private final Shell activeShell;
/**
* Constructs a new instance of ActiveShellExpression
*
* @param activeShell
* The shell to match with the active shell; null
* if it will match any active shell.
*/
public ActiveShellExpression(final Shell activeShell) {
this.activeShell = activeShell;
}
/**
* Expression information for this expression. Namely active shell and
* active workbench window name.
*
* @since 3.2
*/
@Override
public final void collectExpressionInfo(final ExpressionInfo info) {
info.addVariableNameAccess(ISources.ACTIVE_SHELL_NAME);
info.addVariableNameAccess(ISources.ACTIVE_WORKBENCH_WINDOW_NAME);
}
@Override
protected final int computeHashCode() {
return HASH_INITIAL * HASH_FACTOR + hashCode(activeShell);
}
@Override
public final boolean equals(final Object object) {
if (object instanceof ActiveShellExpression) {
final ActiveShellExpression that = (ActiveShellExpression) object;
return equals(this.activeShell, that.activeShell);
}
return false;
}
/**
* Evaluates this expression. If the active shell defined by the context
* matches the shell from this expression, then this evaluates to
* EvaluationResult.TRUE. Similarly, if the active workbench
* window shell defined by the context matches the shell from this
* expression, then this evaluates to EvaluationResult.TRUE.
*
* @param context
* The context from which the current state is determined; must
* not be null.
* @return EvaluationResult.TRUE if the shell is active;
* EvaluationResult.FALSE otherwise.
*/
@Override
public final EvaluationResult evaluate(final IEvaluationContext context) {
if (activeShell != null) {
Object value = context.getVariable(ISources.ACTIVE_SHELL_NAME);
if (!activeShell.equals(value)) {
value = context
.getVariable(ISources.ACTIVE_WORKBENCH_WINDOW_SHELL_NAME);
if (!activeShell.equals(value)) {
return EvaluationResult.FALSE;
}
}
}
return EvaluationResult.TRUE;
}
@Override
public final String toString() {
final StringBuilder buffer = new StringBuilder();
buffer.append("ActiveShellExpression("); //$NON-NLS-1$
buffer.append(activeShell);
buffer.append(')');
return buffer.toString();
}
}