| /******************************************************************************* |
| * Copyright (c) 2006 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.internal.expressions; |
| |
| 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.ui.ISources; |
| import org.eclipse.ui.IWorkbenchPart; |
| |
| /** |
| * <p> |
| * An expression that is bound to a particular part instance. |
| * </p> |
| * <p> |
| * This class is not intended for use outside of the |
| * <code>org.eclipse.ui.workbench</code> plug-in. |
| * </p> |
| * |
| * @since 3.2 |
| */ |
| public final class ActivePartExpression extends Expression { |
| |
| /** |
| * The seed for the hash code for all schemes. |
| */ |
| private static final int HASH_INITIAL = ActivePartExpression.class |
| .getName().hashCode(); |
| |
| /** |
| * The part that must be active for this expression to evaluate to |
| * <code>true</code>. This value is never <code>null</code>. |
| */ |
| private final IWorkbenchPart activePart; |
| |
| /** |
| * Constructs a new instance of <code>ActivePartExpression</code> |
| * |
| * @param activePart |
| * The part to match with the active part; may be |
| * <code>null</code> |
| */ |
| public ActivePartExpression(final IWorkbenchPart activePart) { |
| if (activePart == null) { |
| throw new NullPointerException("The active part must not be null"); //$NON-NLS-1$ |
| } |
| this.activePart = activePart; |
| } |
| |
| public final void collectExpressionInfo(final ExpressionInfo info) { |
| info.addVariableNameAccess(ISources.ACTIVE_PART_NAME); |
| } |
| |
| protected final int computeHashCode() { |
| return HASH_INITIAL * HASH_FACTOR + hashCode(activePart); |
| } |
| |
| public final boolean equals(final Object object) { |
| if (object instanceof ActivePartExpression) { |
| final ActivePartExpression that = (ActivePartExpression) object; |
| return equals(this.activePart, that.activePart); |
| } |
| |
| return false; |
| } |
| |
| public final EvaluationResult evaluate(final IEvaluationContext context) { |
| final Object variable = context.getVariable(ISources.ACTIVE_PART_NAME); |
| if (equals(activePart, variable)) { |
| return EvaluationResult.TRUE; |
| } |
| return EvaluationResult.FALSE; |
| } |
| |
| public final String toString() { |
| final StringBuffer buffer = new StringBuffer(); |
| buffer.append("ActivePartExpression("); //$NON-NLS-1$ |
| buffer.append(activePart); |
| buffer.append(')'); |
| return buffer.toString(); |
| } |
| } |