Copyright (c) 2000, 2008 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, 2008 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.core.internal.expressions;

import java.util.Arrays;

import org.w3c.dom.Element;

import org.eclipse.core.expressions.EvaluationContext;
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.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;

public class ResolveExpression extends CompositeExpression {

	private String fVariable;
	private Object[] fArgs;

	private static final String ATT_VARIABLE= "variable";  //$NON-NLS-1$
	private static final String ATT_ARGS= "args";  //$NON-NLS-1$

	
The seed for the hash code for all resolve expressions.
/**
	 * The seed for the hash code for all resolve expressions.
	 */
	private static final int HASH_INITIAL= ResolveExpression.class.getName().hashCode();

	public ResolveExpression(IConfigurationElement configElement) throws CoreException {
		fVariable= configElement.getAttribute(ATT_VARIABLE);
		Expressions.checkAttribute(ATT_VARIABLE, fVariable);
		fArgs= Expressions.getArguments(configElement, ATT_ARGS);
	}

	public ResolveExpression(Element element) throws CoreException {
		fVariable= element.getAttribute(ATT_VARIABLE);
		Expressions.checkAttribute(ATT_VARIABLE, fVariable.isEmpty() ? null : fVariable);
		fArgs= Expressions.getArguments(element, ATT_ARGS);
	}

	public ResolveExpression(String variable, Object[] args) {
		Assert.isNotNull(variable);
		fVariable= variable;
		fArgs= args;
	}

	@Override
	public EvaluationResult evaluate(IEvaluationContext context) throws CoreException {
		Object variable= context.resolveVariable(fVariable, fArgs);
		if (variable == null) {
			throw new CoreException(new ExpressionStatus(
				ExpressionStatus.VARIABLE_NOT_DEFINED,
				Messages.format(ExpressionMessages.ResolveExpression_variable_not_defined, fVariable)));
		}
		return evaluateAnd(new EvaluationContext(context, variable));
	}

	@Override
	public void collectExpressionInfo(ExpressionInfo info) {
		ExpressionInfo other= new ExpressionInfo();
		super.collectExpressionInfo(other);
		if (other.hasDefaultVariableAccess()) {
			info.addVariableNameAccess(fVariable);
		}
		info.mergeExceptDefaultVariable(other);
	}

	@Override
	public boolean equals(final Object object) {
		if (!(object instanceof ResolveExpression))
			return false;

		final ResolveExpression that= (ResolveExpression)object;
		return this.fVariable.equals(that.fVariable)
				&& equals(this.fArgs, that.fArgs)
				&& equals(this.fExpressions, that.fExpressions);
	}

	@Override
	protected int computeHashCode() {
		return HASH_INITIAL * HASH_FACTOR + hashCode(fExpressions)
			* HASH_FACTOR + hashCode(fArgs)
			* HASH_FACTOR + fVariable.hashCode();
	}

	@Override
	public String toString() {
		StringBuilder builder = new StringBuilder(getClass().getSimpleName());
		builder.append(" [variable=").append(fVariable); //$NON-NLS-1$
		if (fArgs != null) {
			builder.append(", args=").append(Arrays.toString(fArgs)); //$NON-NLS-1$
		}
		Expression[] children = getChildren();
		if (children.length > 0) {
			builder.append(", children="); //$NON-NLS-1$
			builder.append(Arrays.toString(children));
		}
		builder.append("]"); //$NON-NLS-1$
		return builder.toString();
	}
}