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/*******************************************************************************
* Copyright (c) 2009 Cloudsmith Inc. 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:
* Cloudsmith Inc. - initial API and implementation
*******************************************************************************/
package org.eclipse.equinox.internal.p2.ql.expression;
import java.lang.reflect.*;
import java.util.Iterator;
import org.eclipse.equinox.p2.metadata.IRequirement;
import org.eclipse.equinox.p2.ql.*;
/**
* <p>An expression that performs member calls to obtain some value
* from some object instance. It uses standard bean semantics so
* that an attempt to obtain "value" will cause an
* attempt to call <code>getValue()</code> and if no such method
* exists, <code>isValue()</code> and if that doesn't work either,
* <code>value()</code>.</p>
*/
abstract class Member extends Unary {
static Member createDynamicMember(Expression operand, String name) {
return new DynamicMember(operand, name);
}
static final Object[] NO_ARGS = new Object[0];
final String name;
final Expression[] argExpressions;
static abstract class CapabilityIndexMethod extends Member {
public CapabilityIndexMethod(Expression operand, String name, Expression[] args) {
super(operand, name, args);
}
final ICapabilityIndex getSelf(IEvaluationContext context) {
Object self = operand.evaluate(context);
if (self instanceof ICapabilityIndex)
return (ICapabilityIndex) self;
throw new IllegalArgumentException("lhs of member expected to be an ICapabilityIndex implementation"); //$NON-NLS-1$
}
public final Object evaluate(IEvaluationContext context) {
return evaluateAsIterator(context);
}
boolean isCollection() {
return true;
}
}
static final class CapabilityIndex_satisfiesAny extends CapabilityIndexMethod {
public CapabilityIndex_satisfiesAny(Expression operand, Expression[] argExpressions) {
super(operand, KEYWORD_SATISFIES_ANY, NAry.assertLength(argExpressions, 1, 1, KEYWORD_SATISFIES_ANY));
}
@SuppressWarnings("unchecked")
public Iterator<?> evaluateAsIterator(IEvaluationContext context) {
return getSelf(context).satisfiesAny((Iterator<IRequirement>) argExpressions[0].evaluateAsIterator(context));
}
}
static final class CapabilityIndex_satisfiesAll extends CapabilityIndexMethod {
public CapabilityIndex_satisfiesAll(Expression operand, Expression[] argExpressions) {
super(operand, KEYWORD_SATISFIES_ALL, NAry.assertLength(argExpressions, 1, 1, KEYWORD_SATISFIES_ALL));
}
@SuppressWarnings("unchecked")
public Iterator<?> evaluateAsIterator(IEvaluationContext context) {
return getSelf(context).satisfiesAll((Iterator<IRequirement>) argExpressions[0].evaluateAsIterator(context));
}
}
public boolean accept(IExpressionVisitor visitor) {
if (super.accept(visitor))
for (int idx = 0; idx < argExpressions.length; ++idx)
if (!argExpressions[idx].accept(visitor))
return false;
return true;
}
Member(Expression operand, String name, Expression[] args) {
super(operand);
this.name = name;
this.argExpressions = args;
}
public int getExpressionType() {
return TYPE_MEMBER;
}
public void toString(StringBuffer bld) {
if (operand == Variable.ITEM || operand == Variable.EVERYTHING)
bld.append(name);
else {
appendOperand(bld, operand, getPriority());
bld.append('.');
bld.append(name);
}
if (argExpressions.length > 0) {
bld.append('(');
Array.elementsToString(bld, argExpressions);
bld.append(')');
}
}
String getOperator() {
return OPERATOR_MEMBER;
}
int getPriority() {
return PRIORITY_MEMBER;
}
static final class DynamicMember extends Member {
private static final Class<?>[] NO_ARG_TYPES = new Class[0];
private static final String GET_PREFIX = "get"; //$NON-NLS-1$
private static final String IS_PREFIX = "is"; //$NON-NLS-1$
DynamicMember(Expression operand, String name) {
super(operand, name, Expression.emptyArray);
if (!(name.startsWith(GET_PREFIX) || name.startsWith(IS_PREFIX)))
name = GET_PREFIX + Character.toUpperCase(name.charAt(0)) + name.substring(1);
this.methodName = name;
}
private Class<?> lastClass;
private Method method;
private String methodName;
public Object evaluate(IEvaluationContext context) {
return invoke(operand.evaluate(context));
}
boolean isReferencingTranslations() {
return VARIABLE_TRANSLATIONS.equals(name);
}
Object invoke(Object self) {
if (self == null)
throw new IllegalArgumentException("Cannot access member " + name + " in null"); //$NON-NLS-1$//$NON-NLS-2$
Class<?> c = self.getClass();
if (lastClass == null || !lastClass.isAssignableFrom(c)) {
Method m;
for (;;) {
try {
m = c.getMethod(methodName, NO_ARG_TYPES);
if (!Modifier.isPublic(m.getModifiers()))
throw new NoSuchMethodException();
break;
} catch (NoSuchMethodException e) {
if (methodName.startsWith(GET_PREFIX))
// Switch from using getXxx() to isXxx()
methodName = IS_PREFIX + Character.toUpperCase(name.charAt(0)) + name.substring(1);
else if (methodName.startsWith(IS_PREFIX))
// Switch from using isXxx() to xxx()
methodName = name;
else
throw new IllegalArgumentException("Cannot find a public member " + name + " in a " + self.getClass().getName()); //$NON-NLS-1$//$NON-NLS-2$
}
}
// Since we already checked that it's public. This will speed
// up the calls a bit.
m.setAccessible(true);
lastClass = c;
method = m;
}
Exception checked;
try {
return method.invoke(self, NO_ARGS);
} catch (IllegalArgumentException e) {
throw e;
} catch (IllegalAccessException e) {
checked = e;
} catch (InvocationTargetException e) {
Throwable cause = e.getTargetException();
if (cause instanceof RuntimeException)
throw (RuntimeException) cause;
if (cause instanceof Error)
throw (Error) cause;
checked = (Exception) cause;
}
throw new RuntimeException("Problem invoking " + methodName + " on a " + self.getClass().getName(), checked); //$NON-NLS-1$ //$NON-NLS-2$
}
}
}
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