AstFunction.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/* Generated By:JJTree: Do not edit this line. AstFunction.java */
package org.apache.el.parser;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import javax.el.ELClass;
import javax.el.ELException;
import javax.el.FunctionMapper;
import javax.el.LambdaExpression;
import javax.el.ValueExpression;
import javax.el.VariableMapper;

import org.apache.el.lang.EvaluationContext;
import org.apache.el.util.MessageFactory;

/**
 * @author Jacob Hookom [jacob@hookom.net]
 */
public final class AstFunction extends SimpleNode {

    protected String localName = "";

    protected String prefix = "";


    public AstFunction(int id) {
        super(id);
    }


    public String getLocalName() {
        return localName;
    }


    public String getOutputName() {
        if (this.prefix == null) {
            return this.localName;
        } else {
            return this.prefix + ":" + this.localName;
        }
    }


    public String getPrefix() {
        return prefix;
    }


    @Override
    public Class<?> getType(EvaluationContext ctx) throws ELException {

        FunctionMapper fnMapper = ctx.getFunctionMapper();

        // quickly validate again for this request
        if (fnMapper == null) {
            throw new ELException(MessageFactory.get("error.fnMapper.null"));
        }
        Method m = fnMapper.resolveFunction(this.prefix, this.localName);
        if (m == null) {
            throw new ELException(MessageFactory.get("error.fnMapper.method", this.getOutputName()));
        }
        return m.getReturnType();
    }


    @Override
    public Object getValue(EvaluationContext ctx) throws ELException {

        FunctionMapper fnMapper = ctx.getFunctionMapper();

        // quickly validate again for this request
        if (fnMapper == null) {
            throw new ELException(MessageFactory.get("error.fnMapper.null"));
        }
        Method m = fnMapper.resolveFunction(this.prefix, this.localName);

        if (m == null && this.prefix.length() == 0) {
            // TODO: Do we need to think about precedence of the various ways
            // a lambda expression may be obtained from something that
            // the parser thinks is a function?
            Object obj = null;
            if (ctx.isLambdaArgument(this.localName)) {
                obj = ctx.getLambdaArgument(this.localName);
            }
            if (obj == null) {
                VariableMapper varMapper = ctx.getVariableMapper();
                if (varMapper != null) {
                    obj = varMapper.resolveVariable(this.localName);
                    if (obj instanceof ValueExpression) {
                        // See if this returns a LambdaExpression
                        obj = ((ValueExpression) obj).getValue(ctx);
                    }
                }
            }
            if (obj == null) {
                obj = ctx.getELResolver().getValue(ctx, null, this.localName);
            }
            if (obj instanceof LambdaExpression) {
                // Build arguments
                int i = 0;
                while (obj instanceof LambdaExpression && i < jjtGetNumChildren()) {
                    Node args = jjtGetChild(i);
                    obj = ((LambdaExpression) obj).invoke(((AstMethodParameters) args).getParameters(ctx));
                    i++;
                }
                if (i < jjtGetNumChildren()) {
                    // Haven't consumed all the sets of parameters therefore
                    // there were too many sets of parameters
                    throw new ELException(MessageFactory.get("error.lambda.tooManyMethodParameterSets"));
                }
                return obj;
            }

            // Call to a constructor or a static method
            obj = ctx.getImportHandler().resolveClass(this.localName);
            if (obj != null) {
                return ctx.getELResolver().invoke(ctx, new ELClass((Class<?>) obj), "<init>", null,
                        ((AstMethodParameters) this.children[0]).getParameters(ctx));
            }
            obj = ctx.getImportHandler().resolveStatic(this.localName);
            if (obj != null) {
                return ctx.getELResolver().invoke(ctx, new ELClass((Class<?>) obj), this.localName, null,
                        ((AstMethodParameters) this.children[0]).getParameters(ctx));
            }
        }

        if (m == null) {
            throw new ELException(MessageFactory.get("error.fnMapper.method", this.getOutputName()));
        }

        // Not a lambda expression so must be a function. Check there is just a
        // single set of method parameters
        if (this.jjtGetNumChildren() != 1) {
            throw new ELException(MessageFactory.get("error.function.tooManyMethodParameterSets", getOutputName()));
        }

        Node parameters = jjtGetChild(0);
        Class<?>[] paramTypes = m.getParameterTypes();
        Object[] params = null;
        Object result = null;
        int inputParameterCount = parameters.jjtGetNumChildren();
        int methodParameterCount = paramTypes.length;
        if (inputParameterCount == 0 && methodParameterCount == 1 && m.isVarArgs()) {
            params = new Object[] { null };
        } else if (inputParameterCount > 0) {
            params = new Object[methodParameterCount];
            try {
                for (int i = 0; i < methodParameterCount; i++) {
                    if (m.isVarArgs() && i == methodParameterCount - 1) {
                        if (inputParameterCount < methodParameterCount) {
                            params[i] = new Object[] { null };
                        } else if (inputParameterCount == methodParameterCount &&
                                isArray(parameters.jjtGetChild(i).getValue(ctx))) {
                            params[i] = parameters.jjtGetChild(i).getValue(ctx);
                        } else {
                            Object[] varargs = new Object[inputParameterCount - methodParameterCount + 1];
                            Class<?> target = paramTypes[i].getComponentType();
                            for (int j = i; j < inputParameterCount; j++) {
                                varargs[j - i] = parameters.jjtGetChild(j).getValue(ctx);
                                varargs[j - i] = coerceToType(ctx, varargs[j - i], target);
                            }
                            params[i] = varargs;
                        }
                    } else {
                        params[i] = parameters.jjtGetChild(i).getValue(ctx);
                    }
                    params[i] = coerceToType(ctx, params[i], paramTypes[i]);
                }
            } catch (ELException ele) {
                throw new ELException(MessageFactory.get("error.function", this.getOutputName()), ele);
            }
        }
        try {
            result = m.invoke(null, params);
        } catch (IllegalAccessException iae) {
            throw new ELException(MessageFactory.get("error.function", this.getOutputName()), iae);
        } catch (InvocationTargetException ite) {
            Throwable cause = ite.getCause();
            if (cause instanceof ThreadDeath) {
                throw (ThreadDeath) cause;
            }
            if (cause instanceof VirtualMachineError) {
                throw (VirtualMachineError) cause;
            }
            throw new ELException(MessageFactory.get("error.function", this.getOutputName()), cause);
        }
        return result;
    }


    private boolean isArray(Object obj) {
        if (obj == null) {
            return false;
        }
        return obj.getClass().isArray();
    }


    public void setLocalName(String localName) {
        this.localName = localName;
    }


    public void setPrefix(String prefix) {
        this.prefix = prefix;
    }


    @Override
    public String toString() {
        return ELParserTreeConstants.jjtNodeName[id] + "[" + this.getOutputName() + "]";
    }
}